BILTEN PRIRODE PARK PARKA NATURE BULLETINTako su u samom polju brojnije i èešæe limnofilne i neke neutrofilne vrste, poput sunèanice, crvenperke, babuške, štuke, patuljastog

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BILTEN PRIRODE PARKPARKA NATURE BULLETINBILTEN PRIRODE PARKPARKA NATURE BULLETIN

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Bilten parka prirode

Nature Park BulletinLonjsko polje

VOL. 4/NO. 1/2, 2002.

Ovaj projekt je izraðen uz pomoæ LIFE financijskog instrumenta Europske unije

This project has been carried out with the contribution of the LIFE financial instrument of the European Community

Nakladnik / Published by:

Glavni i odgovorni urednik / Editor in chief:

Uredništvo / Editorial board:

Tajnica uredništva / Administrative secretary:

Adresa uredništva / Adress of the Editorial Board:

Tel./faks:

E-mail:

Prijevod / Translation:

Lektor i korektor

Naklada:

Tisak

Javna ustanova "Park prirode Lonjsko polje"Lonjsko Polje Nature Park Public ServiceHR-44324 Jasenovac, Trg kralja Petra Svaèiæa bbHrvatska / Croatia

Goran Gugiæ

Darko Kovaèiæ, Radenko De�eliæ, Martin Schneider-Jacoby

Marija Kušina

Javna ustanova "Park prirode Lonjsko Polje"Bilten,HR-44324 Jasenovac,Trg kralja Petra Svaèiæa bb,HRVATSKA / CROATIA

++385 (0)44 672 080;

[email protected]

Graham McMaster

Ivan Jindra

Izlazi dva puta godišnje / The Bulletin appears twice yearly

500 primjeraka

Gratis tiskara - Kutina

IMPRESSUM

Bilten parka prirodeLonjsko poljeNature Park BulletinVol. 4/No. 1/2, 2002

3

SADR�AJ


5

POŠTOVANI ÈITATELJU ...................................................................................................................... 81. UVOD ..................................................................................................................................................... 9

1.1. LONJSKO POLJE ........................................................................................................................ 91.2. IHTIOLOŠKE ZNAÈAJKE DUNAVSKOGA SLIJEVA ..................................................................... 11

1.2.1. Znaèenje poplavnih podruèja i moèvara za ribe .................................................................. 131.3. DOSADAŠNJE SPOZNAJE O IHTIOFAUNI ................................................................................ 131.4. ZNAÈENJE RIBA .......................................................................................................................... 15

1.4.1. Ekonomsko znaèenje riba ................................................................................................... 161.4.2. Športsko-rekreativno znaèenje riba .................................................................................... 16

2. REZULTATI ISTRA�IVANJA .................................................................................................................. 162.1. REZULTATI TERENSKIH ISTRA�IVANJA ................................................................................... 162.2. STRUKTURA ZAJEDNICE RIBA LONJSKOG POLJA ................................................................ 17

3. STATUS UGRO�ENOSTI ........................................................................................................................ 273.1. Endemi ......................................................................................................................................... 273.2. Nestale vrste ................................................................................................................................. 273.3. Ugro�ene vrste ............................................................................................................................. 273.4. Zaštiæene vrste ............................................................................................................................. 28

4.EKOLOŠKE ZNAÈAJKE RIBLJIH ZAJEDNICA ....................................................................................... 294.1. Odabir staništa i sklonost prema brzini toka ............................................................................... 294.2. Reproduktivne znaèajke i mrijesna staništa ................................................................................. 314.3. Prehrana ....................................................................................................................................... 314.4. Dobna struktura ............................................................................................................................ 314.5. Migratorne vrste ............................................................................................................................ 32

5. IHTIOPRODUKTIVNOST ........................................................................................................................ 335.1. Kondicijsko stanje ribljih zajednica ................................................................................................ 35

6. KAKVOÆA STANIŠTA I INDIKATORSKE VRSTE .................................................................................. 377. PROBLEMATIKA I ŠTETE OD UNESENIH VRSTA .............................................................................. 408. STRUKTURA ZAJEDNICA RIBA OPISANA POMOÆU INDEKSA RAZNOLIKOSTI ............................... 439. PROBLEMI POVEZANI SA SMANJENJEM RIBLJIH POPULACIJA ..................................................... 45

9.1. Nestanak i promjena prirodnih uvjeta staništa ............................................................................. 459.2. Oneèišæenje ................................................................................................................................. 459.3. Melioracije .................................................................................................................................... 469.4. Turizam ........................................................................................................................................ 469.5. Ostali razlozi ................................................................................................................................. 47

10. DOSADAŠNJI NAÈIN KORIŠTENJA RIBARSTVA ............................................................................... 4810.1. Utjecaji na riblji fond ................................................................................................................... 48

10.1.1. Antropogeno djelovanje .................................................................................................... 4810.1.2. Športsko-rekreativni ribolov ............................................................................................... 4910.1.3. Ugro�enost ribljih vrsta ...................................................................................................... 50

11. PRIJEDLOG ZAŠTITNIH MJERA ........................................................................................................ 5111.1. Zaštita mrijestilišta i ostalih otvorenih voda ................................................................................ 5111.2. Monitoring .................................................................................................................................. 5311.3. Suradnja s lokalnim puèanstvom ................................................................................................ 5411.4. Obaviještenost javnosti .............................................................................................................. 5411.5. Inspekcijske i èuvarske slu�be .................................................................................................... 54

12. LITERATURA ....................................................................................................................................... 56

DEAR READER .................................................................................................................................... 81. INTRODUCTION .................................................................................................................................... 9

1.1 LONJSKO POLJE .......................................................................................................................... 91.2. ICHTHYOLOGICAL CHARACTERISTICS OF THE DANUBE DRAINAGE BASIN ...................... 11

1.2.1. The significance of the floodplain and swamps for fish ........................................................ 131.3. KNOWLEDGE ABOUT THE ICHTHYOFAUNA ACQUIRED TO DATE ......................................... 131.4. THE IMPORTANCE OF FISH ........................................................................................................ 15

1.4.1. Economic significance of fish ............................................................................................... 151.4.2. The sporting and recreational importance of fish ................................................................. 16

2. STRUCTURE OF THE FISH COMMUNITY OF LONSJKO POLJE ....................................................... 162.1. RESULTS OF FIELD RESEARCH ............................................................................................... 162.2. RESULTS ...................................................................................................................................... 17

3. STATUS OF ENDANGERMENT ............................................................................................................. 273.1. Endemic species ........................................................................................................................... 273.2. Vanished species .......................................................................................................................... 273.3. Endangered species ...................................................................................................................... 273.4. Protected species ......................................................................................................................... 28

4. ECOLOGICAL CHARACTERISTICS OF THE FISH COMMUNITIES .................................................... 294.1. Selection of habitat and liking for current velocity ........................................................................ 294.2. Reproductive features and spawning habitats .............................................................................. 314.3. Food .............................................................................................................................................. 314.4. Age structure ................................................................................................................................. 314.5. Migratory species .......................................................................................................................... 32

5. ICHTHYOPRODUCTIVENESS .............................................................................................................. 335.1. Fish community condition factors ................................................................................................. 35

6. HABITAT QUALITY AND INDICATOR SPECIES .................................................................................. 377. THE PROBLEM OF AND HARM FROM INTRODUCED SPECIES ....................................................... 408. THE STRUCTURE OF FISH COMMUNITIES DESCRIBED WITH THE USE OF THE INDEX

OF DIVERSITY ....................................................................................................................................... 439. PROBLEMS RELATED WITH THE REDUCTION OF FISH POPULATIONS ........................................ 45

9.1. Disappearance and change of natural habitat conditions ............................................................ 459.2. Pollution ........................................................................................................................................ 459.3. River engineering ......................................................................................................................... 469.4. Tourism ......................................................................................................................................... 469.5. Other reasons .............................................................................................................................. 47

10. FISHING AS PRACTICED TO DATE ................................................................................................... 4810.1. Impacts on the fish stocks .......................................................................................................... 48

10.1.1. Human activities ................................................................................................................. 4810.1.2. Sporting and recreational fishing ........................................................................................ 4910.1.3. Endangerment of fish species ........................................................................................... 50

11. PROPOSAL OF CONSERVATION MEASURES ................................................................................. 5111.1. Protection of spawning grounds and other open waters ............................................................. 5111.2. Monitoring ................................................................................................................................... 5311.3. Collaboration with the local population ....................................................................................... 5411.4. Public information ....................................................................................................................... 5411.5. Inspection and warden services ................................................................................................. 55

12. LITERATURE ...................................................................................................................................... 56

CONTENTS


7

Dear Reader,

If we happened to meet in - for example - the Park'sInfo Point in Èigoæ, and I, as inquisitive director, askedyou what you associated Lonjsko Polje Nature Parkwith, how would you respond? You would perhapspoint your finger at the stork nesting on thesurrounding rooftops. Great! Or perhaps you wouldindicate the wooden houses of Posavina - ah, thenyou have an eye for the cultural heritage! Or perhapsyou would indicate the white-tailed eagle soaring highover Lukmarèica Forest. Oh, you're a frequent visitorto Lonjsko Polje, then. If you wanted to take me toÈigoæ's Tišina - an old backwater of the Sava River, Iwould think: either some impassioned angler, orsomeone who deals with the problem of theconservation of this protected area. For Tišina pointsto the silent world of fish, and it is tightly linked to thewater - the ruler of Lonjsko Polje. For the fish of notonly the Sava but also the whole Danube drainagebasin, this area is essential, and it is one of theremaining refuges - if not perhaps the largest - for thespawning of several important and imperilledspecies. Some etymologists say that the name of thevillage of Krapje, in the heart of the park of today,derives from the word krap, Karpfen (Ger.), carp. Forthe people of Posavina, fish were one of the basicresources for their survival. They devised fishingimplements and techniques that responded to thepiscine spirit, if we can put it that way. The MoslavinaMuseum in Kutina put on an exhibition on the topicthat is very worthwhile. Traditional fishing is part of thecultural heritage and identity of Posavina, and shouldhence be preserved. However, today, in a time ofbustle and hurry, of a life that is increasinglyexhausting, more and more people seek an innerpeace for themselves in angling, fishing for sport andrecreation. The Park's Administration has to beconcerned with all these things. And this is actuallythe reason why we initiated this ichthyological study,based on field research undertaken during 2001 and2002. In our opinion, the results of this study ought tobe accessible to the general public, and so we havedecided to dedicate this number of the Lonjsko PoljeNature Park Bulletin to it. Management of the fishstocks in the area of the park will be based on thisstudy. At the end, it remains for me to thank ProfessorMilorad Mrakovèiæ DSc and his team for elaboratingthis study, and to the European Commission forfinancial support, which has enabled us to prepareand print this bulletin. I hope that this bulletin, in eitherthe English or the Croatian version, will make thesilent fishy world of Lonjsko Polje Nature Park just alittle bit more familiar to our readers.

Goran Gugiæ, managing director

Poštovani èitatelju!

Kada bismo se sluèajno sreli - recimo - uinformativnom punktu Parka u Èigoæu, ja bih Vas,kao znati�eljni ravnatelj, upitao, po èemu Viprepoznajete park prirode Lonjsko polje? Što bisteodgovorili? Mo�da biste uprli prstom u bijele rode naokolnim krovovima? Odlièno! Ili biste pokazali drveneposavske kuæe? Aha, imate Vi i oko za kulturnubaštinu! Ili biste mi skrenuli pozornost na orlaštekavca koji visoko kru�i nad šumom Lugmarèica?Oho, Vi ste èesto u Lonjskom polju! Kad biste mehtjeli voditi do èigoæke Tišine - starog rukavca rijekeSave, pomislio bih: ili je strastveni ribiè ili se baviproblematikom oèuvanja ovog zaštiæenog podruèja.Naime, èigoæka Tišina ukazuje na nijemi riblji svijet, aon je naju�e vezan uz vodu - vladara nad Lonjskimpoljem. Za ribe ne samo savskog slijeva veæ cijelogdunavskog slijeva ovo je podruèje bitno i jedan je akone i najveæi preostao refugij za nesmetani mrijestnekoliko znaèajnih i ugro�enih vrsta. Neki etimolozitvrde da je ime sela Krapje u srcu današnjeg parkaprirode nastalo od rijeèi krap - Karpfen, što bi nahrvatskome znaèilo šaran. Posavcima su bile ribejedan od osnovnih resursa za opstanak. Izumili suribolovne alatke i tehnike kojima su pogodili - ja bihrekao - riblju «dušu». Muzej Moslavina u Kutini je otome postavio izlo�bu koja je vrlo vrijedna pa�nje.Tradicijski ribolov je dio kulturne baštine i identitetaPosavine, i takvog ga treba oèuvati. Meðutim, danas,u vrijeme �urbe i napornog �ivota, sve više ljudi tra�isvoj unutarnji mir u športsko-rekreativnom ribolovu.Uprava Parka o svemu tome mora voditi brigu. I to jezapravo bio razlog zašto je poèela odmah izraðivatiihtiološku studiju koja se temelji na terenskimistra�ivanjima tijekom 2001. i 2002. godine.Smatrajuæi da bi rezultati studije trebali biti dostupniširoj javnosti, odluèili smo joj posvetiti ovaj brojbiltena Parka prirode Lonjsko polje. Upravljanjeribljim fondom na podruèju Parka osloniti æe se naovu studiju.

Na kraju mi preostaje da zahvalim prof.dr.sc.Miloradu Mrakovèiæu i njegovu timu na izradi studije,a Europskoj komisiji na financijskoj potpori, koja jeomoguæila pripremu i tisak ovog broja biltena. AVama, poštovani èitatelju, �elim da Vam ovaj bilten nahrvatskom odnosno engleskom jeziku pribli�i nijemiriblji svijet parka prirode Lonjsko polje.

Goran Gugiæ, ravnatelj

8 Bilten parka prirodeLonjsko polje

Nature Park BulletinVol. 4/No. 1/2, 2002

1. INTRODUCTION

1.1. LONJSKO POLJE

Most of the natural wetlands have practicallydisappeared in Europe, and human activity hasresulted in the modification of most of the rivers. Thebest examples are such rivers as the Volga,Danube, Rhone, Rhine and Elbe. The straighteningof the rivers and vigorous and far-reaching anti-flood measures of the last few decades haveessentially modified riverine water regimes and themorphology of the rivers, and just a few of them haveretained traces of the original floodplains. With river-impoundment, channel-opening or inundationzone-reduction facilities, changes have occurredamong the fish populations. In many of the fishspecies, various factors have been observedleading to changes in their abundance over time andin geographical area (

). Because of the straightening of the watercourses and reclamation operations, over largeareas, particularly in lowland regions, the waterregime of the habitats has changed. This has adiscernible effect on the composition of wetland andriparian forests and water meadows, and thus thecomposition of the biocoenosis has changed. Thefloodplains of lowland Croatia have a very largeecological value, and hence need to be protected,used rationally, and where necessary themechanisms already built for the management ofthe water level should be adjusted so as to achievethe best ratio between protection of the lowlandareas against flood and the natural andunhampered reproduction and feeding of fish, birdsand other organisms related to the lowlandwetlands.

Lonjsko Polje is located in the alluvial plain of theSava River, 100 km east of Zagreb. It extends about150,000 ha over the Sava plain. South of Zagreb theSava can reasonably be considered to take on thefeatures of a real lowland river. This to a great extentdetermines its course and the appearance of thesurrounding area. Like other such streams, the Savatoo here starts meandering and creating typicalfloodplain areas. Over the years the river hasconstantly shifted and changed the appearance ofthe banks, creating channels and oxbows, impartinga very individual appearance to the landscape.Lonjsko Polje itself is one of the largest unreclaimed

Ackermann, 1973.,Appelbergi sur., 1989., Balon, 1967., Biro, 1977., Botnarius.,1967

1. UVOD

1.1. LONJSKO POLJE

U Europi su prirodna poplavna podruèja veæ gotovonestala, a veæinu rijeka izmijenio je èovjek svojimdjelovanjem. Najbolji su primjeri rijeke Volga, Dunav,Elba, Rhona, Rhina itd. Regulacija i intenzivneprotupoplavne mjere posljednjih su desetljeæa bitnoizmijenile rijeène vodne re�ime i morfologiju rijeka, pasu tek rijetke zadr�ale traèak izvornih poplavnihpodruèja. S izgradnjom objekata koji zatvaraju rijeku,otvaraju kanale ili smanjuju poplavne zone nastajupromjene i na ribljim populacijama. Na mnogimvrstama riba uoèeni su razlièiti razlozi koji su dovelido promjena brojnosti u vremenu i prostoru(Ackermann, 1973., Appelberg i sur., 1989., Balon,1967., Biro, 1977., Botnarius., 1967). Zbogreguliranja vodotoka i hidromelioracija na velikim sepovršinama, osobito u nizinskim podruèjima, mijenjavodni re�im staništa. To ima uoèljiv utjecaj na sastavmoèvarnih i vla�nih šuma i travnjaka, pa se mijenja isastav biocenoza. Poplavna podruèja nizinskeHrvatske imaju veliku ekološku vrijednost, pa ih trebaštititi, racionalno iskorištavati, a po potrebi i ispravljatiizgraðene objekte za upravljanje razinom vode, svekako bi se postigao najbolji omjer izmeðu zaštitenizinskih podruèja od poplava i prirodnoga,nesmetanoga razmno�avanja i prehrane riba, ptica iostalih organizama vezanih uz nizinska moèvarnapodruèja.

Lonjsko polje smješteno je u aluvijalnoj ravnici rijekeSave, 100 kilometara istoèno od Zagreba. Prostire seuz savsku nizinu na oko 150 000 ha. Smatra se daSava ju�no od Zagreba poèinje poprimati znaèajkeprave nizinske rijeke. To umnogome odreðuje njezintok i izgled okolnoga prostora. Kao i drugi takvivodotoci, i Sava ovdje poèinje meandrirati te stvaratitipièna poplavna podruèja. Tijekom niza godina rijekau stalnom napredovanju mijenja izgled obala,stvarajuæi rukavce i mrtvaje, dajuæi osebujan izgledkrajoliku. Samo Lonjsko polje jedna je od najveæihnereguliranih poplavnih nizina u Europi, komplekspoplavnih šuma, moèvara, livada, bara i rijeènihrukavaca. Na podruèju gotovo cijeloga Lonjskogpolja najva�niji je ekološki èimbenik poseban vodnire�im. Osim toga posebnoga vodnog re�ima, koji se

Znaèajke ribljih zajednica parka prirode Lonjsko poljeCharasteristic of the fish communities in Lonjsko Polje Nature Park

Prof.dr.sc. Milorad Mrakovèiæ, Perica Mustafiæ, mr.sc., Marko Æaleta, dipl.ing.,Davor Zanella. mr.sc. Ivana Radiæ, dipl.ing.


9

sastoji od povremenih i periodiènih poplavljivanja,va�nu ulogu u stvaranju velike raznolikosti staništaima mikroreljef. Veæ nekoliko desetaka centimetararazmaka izmeðu ni�ih i viših dijelova terena uzrokujevelike razlike u vodnom re�imu staništa iopskrbljenosti vodom. Tako se na tom podruèjustvorio mozaik meðusobno razlièitih staništa, tipiènihza poplavna podruèja, što se, posve razumljivo,pokazuje i u bogatstvu razlièitih �ivotnih zajednica. Tosu razlièiti tipovi poplavnih i vla�nih šuma, poplavnih ivla�nih travnjaka, razlièiti tipovi moèvarnih i vodenihstaništa (mrtvi rukavci s vodom, staništa na rubovimauz tekuæu i stajaæu vodu), ali i iskopi i kanali, kaoposljedica višegodišnjega ljudskog utjecaja. Zapravosu sva ta staništa nastala u duljem razdoblju zbogspecifiènoga vodnog re�ima u interakciji s ljudskimutjecajima. Zato svaka veæa promjena u vodnomre�imu i/ili iskorištavanju toga prostora nu�no vodiprema promjeni �ivotne zajednice na svakompojedinom biotopu.

Rijeke su otvoreni sustavi, sa smjernicamaisprepletenim (povezanim) kroz èetiri dimenzije:longitudinalno (izvor - rijeèni tok - ušæe), lateralno(rijeka - poplavno podruèje), vertikalno (rijeka -podzemne vode) i vremenski (vremenska ljestvica).Utjecaj èovjeka oèituje se posebno u poremeæajuneke od tih dimenzija. Struktura ribljih zajednica uvelikim europskim rijekama znatno se promijenilatijekom posljednjih 100 godina. Kanalizacija,isušivanje moèvara, sjeèa šuma, izgradnjahidroakumulacija i oneèišæenje od industrije ipoljoprivrede znatno su oštetili ekosustave èitavogadunavskog slijeva. Za svaku rijeku i podruèja oko njevrlo su va�an èimbenik poplave. Snaga erozijeprilikom poplava omoguæava izgradnju prostranihboènih kanala, rukavaca, otoka i moèvara, stvarajuæiveliku raznolikost staništa na kojima se �ivotinjehrane, skrivaju i razmno�avaju. Poplave poma�u uoèuvanju bioraznolikosti, poma�uæi biljkama i�ivotinjama u osvajanju novih ali i postojeæih staništa.Poplave poma�u odr�anju zdravlja rijeke i okolišaoko nje. �ivotinje su na takvim poplavnim podruèjimaprilagoðene tom "poplavnom pulsu", godišnjemnapredovanju i povlaèenju poplavnih voda napoplavno podruèje. Posebno znaèenje poplave imajuza ribe poradi razmno�avanja i zato što im daju znakda je vrijeme za njihove migracije. Kako su ribenajva�niji sastojak biološkog iskorištavanja rijeka, zaracionalno gospodarenje vodama prijeko je potrebnopoznavati barem neke mehanizme koji uzrokujupromjene u ribljim populacijama.

Od presudnoga je znaèenja da poplavna podruèjaomoguæuju ribama i drugim �ivotinjama mjesto koje

floodplains in Europe, a complex of riparian forests,marshes, meadows, pools and oxbows. Overpractically the entire area of Lonjsko Polje the mostimportant ecological factor is the special waterregime. Apart from this special water regime, whichconsists of occasional and periodic inundation, themicrotopography too has an important role in thecreation of great habitat diversity. A difference of justa few dozen centimetres between the lower andhigher parts of the terrain will create majordifferences in the water regime of the habitat and itswater supply. Thus in this area a mosaic of mutuallydifferentiated habitats has been created in the area,habitats typical of floodplain areas, which, naturally,is also seen in the richness of the variousbiocoenoses. These are various types of riparian andmoist forests, water meadows, various types ofwetland and water habitats (water-filled oxbows,habitats at the edges of standing and running water),as well as the cuts and channels that are theconsequences of many years of human impact. Infact all these habitats were created over a longperiod of time in response to the water regime in itsinteraction with anthropogenic factors. And so everymajor change in the water regime and/or the use ofthe space necessarily leads to a change in the livingcommunity in each individual biotope.

Rivers are open systems, with axes linked in fourdimensions: longitudinal (the source the course ofthe river the mouth); lateral (the river the flood plain);vertical (the river the underground water) andtemporal (the time scale). The human impact canparticularly be seen in disturbances of thesedimensions. The structure of the fish communities inthe great European rivers has changed to a majorextent in the last 100 years. Sewage systems, thedraining of the marshes, the felling of forests,construction of artificial reservoirs and pollution byindustry and agriculture have considerably damagedthe ecosystems of the whole of the Danube drainagebasin. For every river and the area around it, floodsare a very important factor. The erosive powergenerated during a flood enables the development ofwide lateral channels, oxbows, islands and marshes,creating enormous diversity of habitats in whichanimals feed, find refuge and reproduce. The floodshelp in the preservation of biodiversity, helping plantsand animals to occupy new and existing habitats.Floods help in the maintenance of the health of ariver and the environment around it. The animals insuch floodplain areas have adapted to the pulse ofthe floods, the annual advance and withdrawal of theflood waters in the flooded area. Floods have aparticular importance for fish with respect toreproduction and because they also give them thesign that the time for migration has begun. Since fishare the most important component of the biologicaluse of the rivers, for rational water management it is




im je potrebno za prehranu i razmno�avanje. Barem70 % svih kralje�njaka oslanja se tijekom svoga�ivota na podruèje uz rijeène rubove. Ti dijelovistvaraju prijelaznu zonu izmeðu rijeke i kopnenihstaništa, osiguravajuæi sklonište, hranu, migracijskekoridore za divlje ali i domaæe �ivotinje. Na temeljudosadašnjih znanstvenih spoznaja zna se da su ribevrlo osjetljive na promjene brzine toka, pregradnjerijeke, destrukcije pojedinih biotopa, zagrijavanjevode, kao i na intenzivno iskorištavanje vode (Descy& Empain, 1984.). Poradi toga protok vode i kolièinakisika, temperatura, prozirnost i oneèišæenjeodreðuju strukturu zajednice riba na pojedinimprostorima. Na�alost, u trajno motrenje rijeka, koje bimoglo dati kolièinske podatke o pojedinim vrstama uvremenu, ihtiološka istra�ivanja uglavnom nisu bilaukljuèena.

Zbog svoje velike raznolikosti ribe su vjerojatnonajslabije poznata skupina kralje�njaka. Prijenekoliko desetljeæa vjerovalo se da je faunaeuropskih slatkih voda sasvim poznata. Meðutim,novije su publikacije jako izmijenile shvaæanje o fauniriba Europe. Opisane su brojne nove vrste, podvrste,pa èak i rodovi riba iz dunavskoga slijeva i drugihpodruèja srednje Europe. Opæenito gledano,europska slatkovodna fauna vrlo je homogena.Unutar nje dunavski bazen zauzima središnjemjesto, a po raznolikosti faune smatra senajbogatijim podruèjem u Europi. Poznato je da uèitavom dunavskom slijevu prebivaju oko 103slatkovodne i brakiène vrste riba (u usporedbi s 227vrsta prisutnih u èitavoj Europi), od èega je nekih 13vrsta uneseno iz drugih biogeografskih podruèja. Uprošlosti je u èitavom dunavskom slijevu �ivjelo 10diadromnih (migratornih) vrsta riba, i to: pet vrstajesetra (

), europska jegulja( ), tri haringe (

) i jedna vrsta sleða( ). Danas seA. nudiventris iA.sturio smatraju izumrlima za dunavski slijev. Vrstedunavskoga slijeva imaju holoarktièku, palearktièku,eurosibirsku, europsku, srednjoeuropsku ilipontokaspijsku rasprostranjenost. Dunavski slijevjedini je prostor središnje Europe s nešto višeendema u fauni riba; ovdje �ivi osam endemskihvrsta, od kojih tri i na podruèju PP Lonjsko polje.

1.2. IHTIOLOŠKE ZNAÈAJKEDUNAVSKOGA SLIJEVA

Acipenser gueldenstaedtii, A. nudiventris, A.

stellatus, A. sturio, and Huso huso

Anguilla anguilla Alosa caspia, A.

immaculata, and A. maeotica

Clupeonella cultiventris

essential to understand at least some of themechanisms that bring about changes in fishpopulations.

What is crucially important is that the inundatedareas provide the fish and other animals the spacethat they need to feed and reproduce.At least 70% ofall vertebrates rely during their life on the areaalongside the edges of the rivers. These parts createa zone of transition between the river and the landhabitats, providing shelter, food and migrationcorridors for wild as well as domestic animals.According to scientific information gained to date it isknown that fish are very sensitive to changes inchanges in the speed of the course, the damming ofrivers, the destruction of individual biotopes, theheating of the water as well as the intensive use ofwater (Descy and Empain, 1984). For this reason,the flow of water and the oxygen content,temperature, transparency and pollution determinethe structure of the fish community in given areas.Unfortunately, ichthyological research has notgenerally been involved in long-term rivermonitoring, and thus the quantitative data aboutgiven species in the time that might have beenprovided have not been available.

Because of their great diversity, fish are probably themost poorly known group of vertebrates. A fewdecades ago, it was believed that the fauna ofEuropean fresh water had been completelyidentified. However, more recent publications greatlymodified the understanding of fish fauna in Europe.Many new species have been described, as well assubspecies and even genera of fish from the Danubebasin and other areas of Central Europe. Looked atin general, European freshwater fauna is veryhomogeneous. Within it, the Danube basic occupiesthe central place, and in terms of fauna diversity isheld to be the richest area of Europe. It is known thatin the whole of the Danube basin there area about103 fresh water and brackish water species of fish(as compared with the 227 species found in thewhole of Europe), of which some 13 species havebeen introduced from other biogeographic areas. Inthe past 10 diadromic (migratory) species lived in thewhole of the Danube basin to be precise: five speciesof sturgeon (

),the European eel ( ), three shads( ) andone species of herring ( ).

1.2. ICHTHYOLOGICALCHARACTERISTICS OF THE DANUBEDRAINAGE BASIN

Acipenser gueldenstaedtii, A.nudiventris, A. stellatus, A. sturio, and Huso huso

Anguilla anguillaAlosa caspia, A. immaculata, and A. maeotica

Clupeonella cultiventris



11

Najugro�enija skupina riba su jesetre, od kojih sedvije smatraju izumrlima, a ostale su ili ugro�ene iliosjetljive svojte. Jedna od najugro�enijih vrstasvakako je i mladica ( ), koja je kritiènougro�ena za dunavski slijev a populacije su jojdrastièno smanjene u posljednjih 20-ak godina.Ugro�ene su i populacije divljega šarana koje polakoistiskuju uzgojene ili unesene svojte.

Veæ je reèeno da je podruèje Lonjskoga polja podviše-manje pulsnim promjenama vodnog re�ima ipoplava. Oscilacije vodostaja uzrokuju velikepromjene, èime se znatno mijenjaju uvjetihidrobiološke produkcije. Znaèenje visine vodostajakao ekološkoga èimbenika riblje proizvodnje proizlaziiz uloge poplavne zone u razmno�avanju riba. Tu suva�ni èimbenici visina vodostaja i du�ina njegovatrajanja. Vode nizinskih krajeva u proljeæe imajuprosjeèno viši vodostaj, no du�ina njegova trajanja irazina vode rijetko se podudaraju s najboljimuvjetima za razmno�avanje riba. Sprega poplava irazmno�avanja riba oèituje se u tome što odrasle ribeu vrijeme visokoga vodostaja masovno migriraju izrijeènih korita u novonastale poplavne zone, gdje,pod utjecajem povišene temperature, teku sna�nihidrobiološki procesi, povoljni za intenzivnu prehranui reprodukciju. Posljedica je dugih poplava - kad seveæina riba uspije izmrijestiti i nakon toga uspješnoothraniti - vrlo velika brojnost populacija u sljedeæojgodini, što nije tako u godinama s kratkim poplavamakad je brojnost nekoliko puta manja. Dakle, vodeniminimum i maksimum poklapaju se s maksimalnim iminimalnim ulovima riba. Va�no je i vrijemenastupanja poplave. Izostanu li poplave ili traju likraæe, odrasle ribe se br�e povlaèe u korito rijeke,izmrijeste se na neprikladnu mjestu, pa tako tegodine izostane gotovo èitava generacija riba. To sesljedeæih godina jasno uoèava na njihovimpopulacijama, što je u predjelu nizinske Hrvatskebitno za naše ekonomski najva�nije vrste riba -šarana, soma i smuða.

S ihtiološkoga gledišta, vode na podruèju PP Lonjskopolje pripadaju donjim ciprinidnim (šaranskim)vodama, a to su vode ispod nadmorske visine od 100metara. Tako su Sava i ostale rijeke zbog slabijegatoka meandrirale, stvarajuæi raznolika staništa:prostrane rukavce, moèvare, mrtvaje i ritove, kaokarakteristiènu sliku ovoga nizinskog krajolika. To jepodruèje, zbog stalnoga nanošenja i talo�enja(sedimentacije) mulja i drugoga materijala ispranogiz viših dijelova vodotoka, vrlo bogato organskim imineralnim tvarima, što ima veliki utjecaj naproizvodnju prirodne hrane, a samim tim i na velièinu ikakvoæu ribljih zajednica.

Hucho hucho

Today A. nudiventris and A. sturio are consideredextinct in the Danube basin. The species of the basinhave Holarctic, Palearctic, Euro-Siberian, European,Central European and Pontic-Caspian distributions.The Danube basin is the only area in Central Europewith a fairly large number of endemic species in thefish fauna; there are eight endemic species here,three of them in the Lonjsko Polje Nature Park area.The group of fish that is the most endangered is thesturgeon, two of them already being consideredextinct, the remainder of them being endangered orvulnerable taxa. One of the most endangeredspecies must be the huchen ( ), which iscritically endangered in the Danube basin, thepopulations of it having been drastically reduced inthe last score or so of years. Also endangered arepopulations of wild carp that are slowly being forcedout by cultivated or introduced taxa.

It has already been said that the Lonjsko Polje area issubject to the more or less pulsing alterations ofwater regime and flooding. Oscillations in the waterlevel bring about great changes, considerablyaltering the conditions of hydrobiological production.The importance of the water level as ecologicalfactor in fish production derives from the role of theflooded area in the reproduction of fish. Importantfactors are the level of water and how long it lasts.Waters of the lowland regions have on average ahigher water level in spring, but the duration and levelof the water rarely coincide with the best conditionsfor reproduction. The greatest match between floodwater and fish reproduction can be seen in the adultfish, during the time of high water level, moving inmass from the courses of the rivers to the newlycreated flooded areas, where, under the influence ofthe higher temperatures, powerful hydrobiologicalprocesses occur, suitable for vigorous feeding andreproduction. The consequence of long floods whenmost fish manage to spawn and after that feedsuccessfully is great population abundance in thenext year, which is not the same in years with shortfloods, after which the numbers are several timessmaller. Thus the minimum and maximum of thewater levels correlate with the maximum andminimum catches. Also important is the time whenthe floods occur. If they do not happen, or if theyoccur only a short time, the adult fish go back fasterinto the river courses, spawn in an unsuitable site,and thus that year almost a whole generation of fishis missing. This is clearly seen in years to come in thepopulations, and in the area of lowland Croatia isessential for the economically most importantspecies of fish carp, catfish and pike-perch.

From the ichthyological point of view, water in thearea of Lonjsko Polje Nature Park is classified aslower cyprinid (carp) water, waters below 100 mamsl. Thus the Sava and the other rivers, because of

Hucho hucho




1.2.1. Znaèenje poplavnih podruèja i moèvara zaribe:

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raznolikost staništa daje podlogu za veæuraznolikost i brojnost vrsta i tako osigurava mnogimvrstama riba hranu i pogodna mjesta zarazmno�avanje; raznolikost zajednica vodi njihovojveæoj stabilnosti

raznolikost staništa pru�a i odlièna mjesta za razvoji odrastanje mladih riba; od osiguravanja dovoljnekolièine hrane do zaštite od predatora

omoguæuju ribama vezu izmeðu vodotoka i drugihvodenih površina

sadr�i stalne vodene površine koje osiguravajuribama sigurno utoèište tijekom suhog razdoblja

Podaci o strukturi populacije ihtiofaune Lonjskogapolja nisu do sada cjelovito obuhvaæeni, nego ihnalazimo fragmentarno u razlièitim studijama idrugim publikacijama. Sustavna istra�ivanjazapoèela su potkraj 19. stoljeæa, a temelje seuglavnom na prikupljenim kazivanjima lokalnih ribarao ulovima, njihovim opisima pojedinih vrsta riba tenavoðenju narodnih i germaniziranih naziva riba.Tako A. Jurinac u svom radu "Prilog fauni zapadneSlavonije" iz 1887. godine spominje 12 vrsta ribaovoga podruè ja (

) te još nekoliko vrsta za koje jesakupio samo puèke nazive (lezbaba, kisir, klinarak).Istra�ivanja nastavljaju Hefele, 1889 i Mediæ, 1901..Tek polovicom 20. stoljeæa poèinju istra�ivanjaihtiofaune širega podruèja, utemeljena naznanstvenim metodama i na pravilima modernetaksonomije. U posljednjih 10-ak godina provedenasu neka djelomièna istra�ivanja ihtiofaune Lonjskogapolja, meðu kojima je i diplomski rad (Suiæ, 1995.) kojise bavio raznolikošæu i sastavom ihtiofaune tenekoliko istra�ivanja zajednice riba širega podruèja usklopu ciljanih ekoloških studija (Mrakovèiæ iKerovec, 1997.).

Buduæi da je u Lonjskom polju jedini oblik ribolovašportsko-rekreativni, ne èudi što nema toènih novijihpodataka o kvalitativnoj i kvantitativnoj strukturiribljega fonda toga podruèja koju bi saèinile ribolovne

1.3. DOSADAŠNJE SPOZNAJE OIHTIOFAUNI

rodov i Cob i t i s , Esox ,

Chondrostoma, Squalus (Leuciscus), Alburnus,

Blicca, Rhodeus, Barbus, Cyprinus, Silurus, Lota,

Leuciscus, Rutilus

the slowness of their courses, have formedmeanders, creating diverse habitats: broadchannels, marshes, oxbows and wetlands, makingup the characteristic image of this lowlandlandscape. This is an area which because of theconstant transport and sedimentation of silt andother materials leached from the higher parts of thewatercourse is very rich in organic and mineralsubstances, which has a great impact on theproduction of natural food, and hence on the size andquality of the fish communities.

habitat diversity provides a base for great diversityand high numbers of species and thus ensuresfood and suitable places for reproduction for manyspecies; the diversity of the communities leads togreater stability among them,

diverse habitats afford excellent places for theyoung to develop and grow; from the provision ofsufficient quantities of food to protection frompredators,

they provide fish with links between the rivers andother water areas,

they include permanent areas of water that providea sure refuge for the fish during periods of drought.

Data about the structure of the population of theichthyofauna of Lonjsko Polje have not been as yetbrought together as a whole in a single place, but canrather be found fragmentarily in various differentstudies and other publications. Systematic researchstarted at the end of the 19th century, and is largelybased on the gathered tales of local fishermen abouttheir catches, their descriptions of individual speciesof fish and the citation of the vernacular andGermanised names for the fish. Thus in his work“Contribution to the Fauna of West Slavonia” of 1887,A. Jurinac mentions 12 species of fish for this area(

) as wellas several species for which he could compile onlythe vernacular terms (lezbaba, kisir, klinarak). Theresearch was continued by Hefele, 1889 and Mediæ,1901.. Only since the mid-20th century has therebeen research into the ichthyofauna over a

1.2.1. The significance of the floodplain andswamps for fish:

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1.3. KNOWLEDGE ABOUT THEICHTHYOFAUNA ACQUIRED TO DATE

the genera Cobitis, Esox, Chondrostoma, Squalus(Leuciscus), Alburnus, Blicca, Rhodeus, Barbus,Cyprinus, Silurus, Lota, Leuciscus, Rutilus



13

organizacije, osim na rubnim podruèjima koja granièes Lonjskim poljem (Zajednice sportskih ribolovnihdruštava Zagreb, Ivaniæ Grad i Sisak). Strukturaulova, koja se utvrðuje izlovom po ribolovnimorganizacijama, ne odgovara stvarnoj strukturi zbogizrazite selektivnosti ribolovnih alata i interesašportskih ribolovaca.

Današnji je sastav ihtiofaune toga podruèja rezultatutjecaja biotièkih i abiotièkih èimbenika. Sve veæaljudska aktivnost u podruèju gornjega toka Save, kaoi u podruèjima njezinih pritoka, rezultira porastomoneèišæenja organskim, anorganskim i radioaktivnimpolutantima te porastom temperature vode, tako dase ihtiopopulacija nizinskog toka i porjeèja Savesigurno razlikuje od prvotne autohtone populacije.Mijenjanje karakteristika ekosustava rezultirapromjenama unutar populacija riba. Promjene uraznolikosti vrsta naglašen su signal koji pokazuje dase u vodenom ekosustavu dogodila znatna i, obièno,dugotrajna promjena jednog ili više èimbenika. Sobzirom na to da riblja zajednica djeluje kao slo�enibioindikator, u kojemu se promjene nakupljaju,njegova signalizacija mora se odgonetnutipostupnom analizom ihtioloških, gospodarstvenih,hidroloških, kemijskih i drugih podataka, kako bi seodredio uzrok ili uzroci promjena u ribljem fonduvodenoga staništa.

U crnomorskom slijevu na podruèju Hrvatske �ivi oko78 vrsta riba. Autohtone su 64 vrste, dok ih je 14,uglavnom u prošlom stoljeæu, uneseno iz drugihkrajeva. Rijeka Sava i svi njezini pritoci dio sudunavskog ili crnomorskog vodnog slijeva. Podruèjenizinskoga dijela rijeke Save bogato je mješovitimribljim populacijama; naseljava ga 50-ak vrsta riba,svrstanih u 13 porodica. Sadašnje stanje ihtiofauneSave i poplavne zone Lonjskoga polja utvrðeno je natemelju literaturnih podataka i na temelju intenzivnihjednogodišnjih istra�ivanja (2001. - 2002.). U samomPP Lonjsko polje naðene su 33 vrste riba iz osamporodica.

wider area, based on scientific methods andaccording to modern taxonomic principles. In the lastdozen years several partially investigations of thefish fauna of Lonjsko Polje have been carried out,including an undergraduate dissertation (Suiæ, 1995)dealing with the diversity and composition of theichthyofauna and several investigations of the fishcommunity of the wider area as part of specificallytargeted ecological studies (Mrakovèiæ and Kerovec,1997).

Since the only kind of fishing in Lonjsko Polje issporting and recreational in nature, there is nowonder that there are no more precise data about thequalitative and quantitative structure of the fishstocks of the area made up by the fishingorganisations, except for the border areas on theedges of Lonjsko Polje (fishing clubs of Zagreb,Ivaniæ Grad and Sisak). The structure of thecommunities, which is determined by the catchaccording to the fishing organisations, does notmatch the real structure of the population, becauseof the markedly selective fishing equipment andinterests of anglers.

The composition of the ichthyofauna of this areatoday is the outcome of the influences of biotic andabiotic factors. Increasing human activity in the areaof the upper course of the Sava, as well as in theareas of its tributaries, has resulted in a rise inpollution with organic, inorganic and radioactivepollutants, as well as a rise in water temperature,with the result that the fish populations of the lowercourse and basin of the Sava of a certainty differ fromthe original indigenous population. Changes in thecharacteristics of the ecosystem have resulted inchanges in the fish populations. Changes in speciesdiversity are an emphatic signal that shows that aconsiderable and usually long-lasting change of oneor more factors has occurred in the aqueousecosystem. Since the fish community works as acomplex bio-indicator, in which changesaccumulate, this signalling must be decoded by aprogressive analysis of ichthyological, economic,hydrologic, chemical and other data, in order todetermine the cause or causes of the changes in thefish stocks of the aqueous habitat.

About 78 species of fish live in the Croatian part ofthe Black Sea drainage basin. Sixty-four species areindigenous, while 14 of them were introduced fromother areas, mainly in the last century. The SavaRiver and its tributaries are all part of the Danube orBlack Sea basin. The area of the lowland part of theSava River is rich in mixed fish populations: it isinhabited by about 50 species, classified into 13families. The current state of the ichthyofauna of theSava and the inundation zone of Lonjsko Polje isdetermined according to data from the literature andaccording to vigorous one year research (2001-2002). In Lonjsko Polje Nature Park itself, 33 speciesof fish from eight families were found.




1.4. ZNAÈENJE RIBA

Ribe su gotovo najbrojniji kralje�njaci u ekosustavu ivrlo su va�ne za kru�enje tvari. Njihova uloga uekosustavu potpuno je otkrivena i odreðena teknedavno Holmlund i Honner, 1999, a svodi se naregulatornu, povezujuæu i informativnu.

Regulatorna uloga ribljih zajednica:

upravljaju dinamikom prehrambenih lanaca

recikliraju nutrijente

prestrukturiraju supstrat dna

poma�u kru�enju ugljika iz vode u atmosferu

odr�avaju proces sedimentacije

odr�avaju raznolikost na razini genoma, vrsta iekosustava.

Uloga u povezivanju trofièkih razina:

povezuju trofièke lance unutar akvatièkogekosustava

veza su trofièkih lanaca vodenog i kopnenogekosustava

transport nutrijenata, ugljika i minerala.

Informativne usluge riba su :

procjena stresa ekosustava

procjena stanja ekosustava

znanstvene i obrazovno-odgojne informacije

prirodno-povijesne informacije.

Znaèenje riba kao hrane mijenja se u pojedinimstoljeæima. Nekad je riba iz rijeka imala velikugospodarsku vrijednost za domaæe stanovništvo,koje je maksimalno gravitiralo prema rijeci i njezinimresursima. Danas riba, osim ekonomske, ima i drugevrijednosti: posebno estetsku, informativnu irekreacijsku.

Ribe su, prema novom "Zakonu o slatkovodnomribarstvu", dijelovi prirode od posebnog interesa zaRepubliku Hrvatsku i imaju njezinu osobitu zaštitu, aiskorištavaju se na odr�ivi naèin koji pridonosioèuvanju biološke raznolikosti ekoloških sustava.

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1.4.1. Ekonomsko znaèenje riba

1.4. THE IMPORTANCE OF FISH

Fish are practically the most numerous vertebratesin the ecosystem and are very important in thecirculation of substances. Their role in the ecosystemwas completely revealed and determined onlyrecently Holmlund i Honner, 1999 and comes downto the regulatory, connecting and informational.

The regulatory role of fish communities:

they control the dynamics of food changes

recycle nutrients

restructure the substrate of the bottom

help in the circulation of carbon from the water intothe atmosphere

maintain the sedimentation process

maintain diversity at the level of genome, speciesand ecosystem

Their role in linking the trophic levels:

the connect the trophic chains inside the aquaticecosystem

they provide a link between the trophic chains ofthe aquatic and terrestrial ecosystems

transport of nutrients, carbons and minerals

The informative roles of fish are:

estimate of ecosystem stress

estimate of state of the ecosystem

scientific and educational information

natural history information.

The importance of fish as food has changed over thecenturies. Once, fish from the rivers had a greatereconomic value for the domestic population, whichtended to the maximum towards the river and itsresources. Today fish, apart from the economic, haveother values too: in particular, aesthetic,informational and recreational.

According to the new Freshwater Fishing Law, fishare parts of nature that are of particular interest to theRepublic of Croatia, and enjoy its particularprotection, and are exploited in a sustainable waythat contributes to the preservation of the biologicaldiversity of the ecological systems.

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1.4.1. Economic significance of fish



15

1.4.2. Športsko-rekreativno znaèenje riba

Prema Lonjskom polju gravitira velik broj športsko-rekreativnih ribolovaca, a i domaæem je stanovništvuribolov tradicionalna djelatnost. Opæenito gledano, uHrvatskoj športsko-rekreativni ribolov istiskujeprivredni jer je vrijednost ribe u njemu daleko veæa.Taj tip ribolova na ovom se podruèju primjenjuje veædugi niz godina, ali katkada donosi parku prirode višeštete nego koristi. Negativni utjecaji na kakvoæuvode, ometanje riba prilikom mrijesta, nedopušteniribolovni alati, pregraðivanje kljuènih vodotokaunutar parka i dr., sve nas više uèvršæuje u zamisli daod športskog ribolova u ovom obliku u parku prirodeLonjsko polje treba odustati. Zakonska podloga semo�e naæi u stavku 1. èlanka 3. Zakona oslatkovodnom ribarstvu, gdje se ribolovnim vodamane smatraju vode posebno zaštiæenih dijelovaprirode, proglašene na temelju posebnoga zakona(nacionalni parkovi i parkovi prirode), ribnjaci,akumulacije, jezera i tekuæe vode koje su rezerviraneza javnu vodoopskrbu ili iz kojih se zahvaæa voda zapiæe. Športsko-rekreativni ribolov treba dopustiti naotvorenim vodama Save i na posebno odreðenimprostorima unutar parka.

Svrha je istra�ivanja bila na temelju sadašnjegastanja ribljih populacija opisati i utvrditi sastav,brojnost i biomasu zajednice riba te predlo�iti osnovuna temelju koje æe se štititi ihtiofauna, ali i gospodaritiihtiofondom.

Ihtiofauna Lonjskoga polja istra�ivana je tijekom2001. i 2002. godine na 20-ak lokaliteta, pri èemu senastojalo obuhvatiti što veæi broj razlièitih vodenih ivla�nih staništa te glavnih vodotoka podruèja.Uzorkovanje je provoðeno pomoæu elektroagregataAGK sa 2,5 kW snage i naponom od 700 Vistosmjerne struje. Uzorkovalo se i mre�ama tipapopuna na onim lokalitetima gdje je konfiguracijaterena to dopuštala. Ulovljeno je više od 5000 riba, odèega je 2686 jedinka svih prisutnih vrsta obraðenorazlièitim ihtiološkim metodama.

Lokaliteti na kojima je istra�ivano:

2. REZULTATI ISTRA�IVANJA

2.1. REZULTATI TERENSKIHISTRA�IVANJA

1.4.2. The sporting and recreational importanceof fish

1. Èigoæ -

A large number of sporting and recreational anglersgravitate towards Lonjsko Polje, while for the localpopulation, fishing is a traditional activity. Looked atin general, in Croatia recreational fishing is drivingout economic fisheries, because the value of the fishin it is far greater. This type of fishing has beenpractised in this area for a number of years, butnevertheless sometimes brings the Lonjsko PoljeNature Park more harm than good. The negativeeffects on the quality of water, disturbance of the fishduring spawning, illegal fishing tools, impoundingkey watercourses in the park and so on all confirm usin the idea that this kind of angling should beabandoned in Lonjsko Polje Nature Park. Afoundation in the law for this can easily be found inArticle 3 Paragraph 3 of the Freshwater Fishing Law,in which the water of specially protected parts ofnature, so pronounced pursuant to a separate law(national and nature parks), fishponds, reservoirs,lakes and running water reserved for public watersupply or from which drinking water is taken are notdeemed to be fishing waters. Sporting andrecreational fishing should be allowed only on theopen waters of the Sava and at specially definedareas inside the park.

The purpose of the research was, according to thecurrent state of the fish populations, to describe andestablish the composition, numerousness andbiomass of the fish community and to propose abase pursuant to which the ichthyofauna can beprotected and the fish stocks can be managed.

The ichthyofauna of Lonjsko Polje was investigatedduring 2001 and 2002 in some score of localities, anendeavour being made to cover as many differentkinds of aquatic and moist habitats and the mainstreams of the area. Sampling was carried out withthe use of an AGK generator, 2.5 kW, 700 V, DC.Sampling was also done with gill nets in those areaswhere the configuration of the land permitted. Morethan 5000 fish were taken, of which 2686 individualsof all the species present were processed withvarious ichthyological methods.

These are the sites at which investigations were made:

excavation in the common by a dike

2. RESULTS

2. 1. RESULTS OF FIELD RESEARCH




1. Èigoæ -2. Èigoæ -3. Èigoæ -4. Mu�ilovèica -5. Mu�ilovèica -6. Mu�ilovèica -7. Suvoj -8. Trebe� -9. Trebe� -10. Trebe� -11. Puska -12. Puska -13. Strug -14. Veliki Strug -

15. Mokro polje -

16. Nova Lonja - Trebe� -17. Košutarica -18. Mlaka -

19. Višnjica -20. Sava -21. Sava -22. Sava -

iskop u polju uz nasipprivremena voda u poljumrtvaja u selu

iskop u polju uz nasipprivremena voda u poljumrtvaja u selu

mrtvaja u selukanal iznad ustavemrtvaja uz nasipstari tok uz selomrtvaja zapadno od selaistoèno od sela

kanal kod mosta za Novskuod �eljeznièkog mosta prema

Mokrom poljupoplavno polje oko Velikog

Struganizvodno èamcem

mrtvaja uz cestu prema Košutaricimrtvaja izmeðu ceste i šume, prema

Mokrom poljumrtvaja uz selo

kod Jasenovca, utok Unekod utoka Trebe�a u Savukod skele Puska Bobovac

Broj vrsta riba naðenih na podruèju PP Lonjsko poljeje za oko 20 od broja koji je zabilje�en u

nizinskom dijelu rijeke Save. U rijeci Savi sepojavljuje veæi broj reofilnih vrsta koje rijetko zalazena poplavna podruèja, ali je njihov povremenidolazak na takva staništa moguæ. Veæina tih"savskih" vrsta zabilje�ena je i na više lokalitetauzvodno i nizvodno od Lonjskoga polja, ali pri našimposljednjim istra�ivanjima nisu ulovljene. Zanimljivoje da nije ulovljena dvoprugasta uklija, iako je vrlobrojna na pojedinim lokalitetima u rijeci Savi. Jedandio vrsta u posljednje vrijeme nije ulovljen u rijeciSavi, a meðu te vrste pripadaju: pliska, sabljarka,prugasti balavac i mali vretenac.

Na podruèju PP Lonjsko polje �ive veæinom one vrstekojima pogoduju mirne vode, dok su stanovnici brzihvoda samo gosti. Dvadeset i osam vrsta nastanjujeovaj prostor oduvijek, dok su ostale unesene, i to iz

2.2. STRUKTURA ZAJEDNICE RIBALONJSKOG POLJA

manji

2. Èigoæ -3. Èigoæ -4. Mu�ilovèica -

5. Mu�ilovèica -6. Mu�ilovèica -7. Suvoj -8. Trebe� -9. Trebe� -10. Trebe� -11. Puska -12. Puska -13. Strug -14. Veliki Strug -

15. Mokro polje -16. Nova Lonja - Trebe� -17. Košutarica -

18. Mlaka -

19. Višnjica -20. Sava -21. Sava -22. Sava -

temporary pool in the commonoxbow in the village

excavation in the common alongthe dike

temporary pool in the commonoxbow in the village

oxbow in the villagechannel above the sluice/damoxbow by the dikeold course by the villageoxbow west of the villageeast of the village

channel by the bridge to Novskafrom the railway bridge towards

Mokro poljefloodplain around Veliki Strug

downstream by boatoxbow along the road towards

Košutaricaoxbow between road and forest,

towards Mokrooxbow by the village

by Jasenovac, confluence with the Unaconfluence of the Trebe� and the Savaby the Puska Bobovac ferry

The number of fish species found in the area ofLonjsko Polje Nature Park is about 20 smaller thanthe number recorded in the lowland part of the SavaRiver. Along the Sava there are many rheophilousspecies that seldom come into the flood plain,although they might well come into such habitatsoccasionally. Most of the Sava species are recordedat several localities upstream and downstream ofLonjsko Polje, but during our recent research werenot actually caught. It is interesting that no schneiderwas caught, although it is extremely numerous atvarious different localities in the Sava River. Some ofthe species have not been caught recently the SavaRiver, among them being the: Danubian bleak,ziehe, striped ruffe and streber

Most of those species that are suited by calm waterlive in the area of the Lonjsko Polje Nature Park,while inhabitants of more rapid water are onlyvisitors. Twenty eight species have always inhabitedthis area, while the others have been introduced,from North America and Asia. Looked at

2.2. STRUCTURE OF THE FISHCOMMUNITY OF LONSJKO POLJE



17

Sjeverne Amerike i iz Azije. Zoogeografski gledano,veæina vrsta ovoga prostora su holoarktièke isrednjoeuropske vrste, koje se u ovom prostorupojavljuju zajedno s mnogim vrstama iz ponto-kaspijske regije. Promatrano podruèje premaBanarescu, 1964. pripada europsko-medite-ranskom ihtiološkom podruèju, koje obilje�ava malibroj potporodica. Najzanimljivija i najbrojnija vrstamaje porodica šaranki ( ), koja je zastupljena sdvadeset i jednom vrstom, što èini oko 63 % vrstaLonjskoga polja i oko 58 % vrsta te porodice koja sepojavljuje u dunavskom slijevu. Velik dio vrsta kojeèine tu porodicu izrazito su limnofilne, dakle ribemirnih, nizinskih vodotoka, kojima je za razmno-�avanje potrebna visoka proljetna temperatura vode ibujna vodena vegetacija (bentoska i plutajuæa), nakoju odla�u svoju ljepljivu ikru (fitofilne vrste).Porodica Percidae zastupljena je s èetiripredstavnika. Na prostoru istra�ivanja ulovljeni sugrgeè, smuð, obièni balavac i rijeèni glavoèiæ.Porodica predstavljena je sa tri vrste (vijun,veliki vijun i èikov), dok je alohtona porodica

zastupljena s dvije vrste (sunèanica,pastrvski grgeè). Pastrvski grgeè je unesena vrstakoju su nedavno ubacili u Èigoæku mrtvaju lokalnišportsko-rekreativni ribolovci.

zastupljene su sa po jednimpredstavnikom u ihtiofauni ovoga podruèja.

Ribe zabilje�ene na podruèju PP Lonjsko polje,ukljuèujuæi i rijeku Savu:

1. štuka ( )

? crnka ( )

2. manjiæ ( )

3. vijun ()

4. vijunica ()

5. piškur ( )

6. koselj ( )7. krupatica ( )8. deverika ( )9. uklija ( )

10. bolen ( )11. mrena ( )

Cyprinidae

Cobitidae

Centrarchidae

Esocidae, Gadidae,

Ictaluridae i Siluridae

Esox lucius Linnaeus, 1758.

Umbra krameri Walbaum, 1792.

Lota lota Linnaeus, 1758.

Cobitis elongatoides Bacescu & Maier,

1969.

Cobitis elongata Heckel & Kner,

1858.

Misgurnus fossilis Linnaeus, 1758.

Abramis ballerus Linnaeus, 1758.

Abramis bjoerkna Linnaeus, 1758.

Abramis brama Linnaeus, 1758.

Alburnus alburnus Linnaeus, 1758.

Aspius aspius Linnaeus, 1758.

Barbus barbus Linnaeus, 1758.

Esocidae

Umbridae

Gadidae

Cobitidae

Cyprinidae

zoogeographically, most of the species of this area ofHolarctic and Central European species, whichappear in the area in conjunction with many speciesfrom the Pontic-Caspian region. The area underobservation, according to Banarescu, 1964. belongsto the European-Mediterranean ichthyological area,which is characterised by the smallness of thenumber of sub-families. The most interesting andmost numerous in species is the carp family( ), which is represented by 221 species,making up about 63% of all species of Lonjsko Poljeand about 58% of the species of the family thatappear at all in the Danube basin. Most of the speciesthat make up this family are markedly limnophilous,that is, they are fish of calm, lowland streams, whoneed high spring water temperature and a flourishingwater vegetation (in the benthos and floating) forreproduction; these phytophil species deposit theirsticky eggs on the weed. The Percidae family isrepresented by four species; in the research area theEuropean perch, pike-perch, ruffe and monkey gobywere taken. The family is represented withthree species (Danubian loach, Balkan loach andweather loach) while the allochthonous family of the

is presented by two species(pumpkinseed and largemouth bass). Thelargemouth bass is an introduced species thatsporting and recreational anglers recently releasedinto the Èigoæ oxbow.

are represented by one species each inthe ichthyofauna of the area.

Fish recorded in the area of Lonjsko Polje NaturePark, including in the Sava River:

1. pike ( )

? European mudminnow ()

2. burbot ( )

3. Danubian loach ()

4. Balkan loach ()

5. weather loach ()

6. blue bream ( )7. silver bream ( )8. common bream (

)9. common bleak (

)10. asp ( )11. barbel ( )

Cyprinidae

Cobitidae

Centrarchidae

Esocidae, Gadidae, Ictaluridaeand Siluridae

Esox lucius Linnaeus, 1758.

Umbra kramerivWalbaum, 1792.

Lota lota Linnaeus, 1758.

Cobitis elongatoidesBacescu & Maier, 1969.

Cobitis elongata Heckel &Kner, 1858.

Misgurnus fossilis Linnaeus,1758.

Abramis ballerus Linnaeus, 1758.

Abramis bjoerkna Linnaeus, 1758.

Abramis brama Linnaeus,1758.

Alburnus alburnus Linnaeus,1758.

Aspius aspius Linnaeus, 1758.

Barbus barbus Linnaeus, 1758.

Esocidae

Umbridae

Gadidae

Cobitidae

Cyprinidae




12. karas ( )13. babuška (

)14. podust (

)15. šaran ( )16. bjelopera krkuša (

)17. krkuša ( )? belica ( )

18. jez ( )19. klen ( )20. bezribica (amurski èebaèok) (

)21. gavèica ( )22. bodorka ( )23. plotica ( )24. crvenperka (

)25. linjak ( )

26. obièni balavac ()

27. grgeè ( )28. smuð ( )29. rijeèni glavoèiæ (

)

30. sunèanica ()

31. pastrvski grgeè ()

32. patuljasti (amerièki) somiæ ()

33. som ( )

Na popisu su i dvije tipiène limnofilne vrste,karakteristiène za bare i mrtvaje, no pri istra�ivanjunisu naðene. Te ribe su crnka ( ) ibelica ( ), naðene u šumi �utici,uzvodno od parka u porjeèju rijeke Lonje. To sukarakteristiène vrste za moèvarna i poplavnastaništa.

S ihtiološkoga stanovišta vrlo je zanimljiv utjecajrijeke Une koja pripada u salmonidne vode i kaotakva utjeèe na sastav ihtiofaune ovoga podruèja.Tako se oèekuje pridolazak vrsta poput kalifornijskepastrve ( ), potoène pastrve

Carassius carassius Linnaeus, 1758.

Carassius auratus Gibelio Bloch.

1783.

Chondrostoma nasus Linnaeus,

1758.

Cyprinus carpio Linnaeus, 1758.

Gobio albipinnatu Lukasch,

1933.

Gobio gobio Linnaeus, 1758.

Lucaspius delineatus Heckel, 1843.

Leuciscus idus Linnaeus, 1758.

Leuciscus cephalus Linnaeus, 1758.

Pseudorazbora

parva Schlegel, 1842.

Rhodeus sericeus Pallas, 1776.

Rutilus rutilus Linnaeus, 1758.

Rutilus pigus Berg, 1932.

Scardinius erithropthalmus

Linnaeus, 1758.

Tinca tinca Linnaeus, 1758.

Gymnocephalus cernuus

Linnaeus, 1758.

Perca fluviatilis Linnaeus, 1758.

Sander lucioperca Linnaeus, 1758.

Neogobius fluviatilis Pallas,

1814.

Lepomis gibbosus Linnaeus,

1758.

Micropterus salmoides

Lacepede, 1802.

Ameiurus

nebulosus Lesueur, 1819.

Silurus glanis Linnaeus, 1758.

Umbra krameri

Lucaspius delineatus

Oncorhynchus mykiss

Percidae

Centrarchidae

Ictaluridae

Siluridae

12. Crucian carp ()

13. Prussian carp ()

14. common nase ()

15. common carp ( )16. whitefin gudgeon (

)17. common gudgeon (

)? sunbleak ( )

18. ide ( )19. common chub (

)20. false harlequin (

)21. bitterling ( )22. common roach ( )23. Dalmatian roach ( )24. common rudd (

)25. tench ( )

26. ruffe ( )27. European perch (

)28. pike-perch ( )29. monkey goby (

)

30. pumpkinseed ()

31. largemouth bass()

32. brown bullhead ()

33. Sheatfish ( )

There are two typical limnophilous species on the list,which are characteristic of pools and oxbows,although during this investigation they were not found.These fish are the European mudminnow (

) and the sunbleak ( ),and were found downstream from the Park in thedrainage area of the Lonja River. They arecharacteristic species of wetland and riparian habitats.

From the ichthyological point of view there is a greatdeal of interest in the impact of the Una River, whichbelongs to salmonid waters, and thus has an impacton the composition of the ichthyofauna of the region.

Carassius carassius Linnaeus,1758.

Carassius auratus GibelioBloch. 1783.

Chondrostoma nasus Linnaeus,1758.

Cyprinus carpio Linnaeus, 1758.

Gobio albipinnatuLukasch, 1933.

Gobio gobio Linnaeus,1758.

Lucaspius delineatus Heckel, 1843.

Leuciscus idus Linnaeus, 1758.

Leuciscus cephalus Linnaeus,1758.

Pseudorazbora parvaSchlegel, 1842.

Rhodeus sericeus Pallas, 1776.

Rutilus rutilus Linnaeus, 1758.

Rutilus pigus Berg, 1932.

Scardinius erithropthalmusLinnaeus, 1758.

Tinca tinca Linnaeus, 1758.

Gymnocephalus cernuus Linnaeus, 1758.

Perca fluviatilis Linnaeus,1758.

Sander lucioperca Linnaeus, 1758.

Neogobius fluviatilis (Pallas,1814.

Lepomis gibbosus Linnaeus,1758.

Micropterus salmoidesLacepede, 1802.

Ameiurus nebulosusLesueur, 1819.

Silurus glanis Linnaeus, 1758.

Umbrakrameri Lucaspius delineatus

Percidae

Centrarchidae

Ictaluridae

Siluridae



19

( ), lipljena ( ) imladice ( ), ali i potoène mrene (

), pijora ( ) ili peša( ). Mladica ( ) je nekad ugornjem toku Save i u Uni bila èesta riba, ali jenjezina brojnost ozbiljno smanjena i o stanjunjezinih populacija danas se malo zna. Na širempodruèju, osim reèenih vrsta, ulove se ili ribièi opazejoš neke unesene vrste, kao bijeli amur (

), sivi glavaš () i bijeli glavaš ( ).

Njihove populacije u divljini vjerojatno nisu brojne ina podruèju PP Lonjsko polje nisu zabilje�ene.Pretpostavlja se da je veæina jedinka tih vrstapobjegla iz šaranskih ribnjaka bli�e okolice ili sunamjerno unesene u rijeku iz razlièitih razloga.

Ribe èiji se pridolazak takoðer mo�e oèekivati u rijeciSavi na podruèju PP Lonjsko polje:

1. dunavska paklara ()

2. keèiga ( )

3. kalifornijska pastrva ()

4. potoèna pastrva ( )5. mladica ( )

6. lipljen ( )

7. crnooka deverika ()

8. dvoprugasta uklija ()

9. potoèna mrena ()

10. velika pliska ()

11. bijeli amur ()

12. keslerova krkuša ()

13. tankorepa krkuša ()

14. sivi glavaš ()

15. bijeli glavaš (

Salmo trutta Thymallus thymallus

Hucho Hucho Barbus

meridionalis Phoxinus phoxinus

Cottus gobio Hucho Hucho

Ctenopha-

ryngodon idella Hypophthalmichthys

molitrix Hypophthalmichthys nobilis

Eudontomyzon danfordi

Regan, 1911.

Acipenser ruthenus Linnaeus, 1758.

Oncorhynchus mykiss

Walbaum,1792.

Salmo trutta L., 1758.

Hucho hucho Linnaeus, 1758.

Thymallus thymallus Linnaeus, 1758.

Abramis sapa Pallas,

1814.

Alburnoides bipuctatus

Bloch, 1782.

Barbus meridionalis Risso,

1828.

Chalcalburnus chalcoides

Gueldenstaedt, 1772.

Ctenopharyngodon idella

Valenciennes, 1844.

Gobio kesslerii Dybowski,

1862.

Gobio uranoscopus

Agassiz, 1828.

Hypophthalmichthys molitrix

Valenciennes, 1844.

Hypophthalmichthys nobilis

Petromyzonidae

Acipenseridae

Salmonidae

Thymallidae

Cyprinidae

Thus it can be expected that species such as therainbow trout ( ), the browntrout ( ) the grayling (

) and huchen ( ), as well assouthern barbel ( ), commonminnow ( ) or common bullhead( ) will come. Huchen ( ) wasonce a frequent fish in the upper course of the Savaand in the Una, but its numbers have seriouslydiminished and little is known today of the populationsof this fish. Over the broader region, apart from thespecies mentioned, some other introduced speciesare either caught or observed by fishermen, such asthe grass carp ( ), silvercarp ( ) and the big headcarp ( ). The populationsof these fish in the wild are probably not large andhave not been recorded in the Lonjsko Polje NaturePark area. It can be assumed that most of theindividuals of these species have escaped from thecarp fishponds close by or were deliberatelyintroduced into the river for various reasons.

Fish that can be assumed to come to the Sava Riverand the Lonjsko Polje Nature Park region.

1. Danubian lamprey ()

2. sterlet ( )

3. rainbow trout ()

4. brown trout ( )5. huchen ( )

6. grayling ( )

7. Danubian bream ( )8. schneider ( )9. southern barbel (

)10. Danubian bleak (

)11. grass carp (

)12. Kessler's gudgeon (

)13. Danubian gudgeon (

)14. silver carp (

)15. big head carp (

Oncorhynchus mykissSalmo trutta Thymallus

thymallus Hucho HuchoBarbus meridionalis

Phoxinus phoxinusCottus gobio Hucho Hucho

Ctenophary-ngodon idellaHypophthalmichthys molitrixHypophthalmichthys nobilis

Eudontomyzon danfordiRegan, 1911.

Acipenser ruthenus Linnaeus, 1758.

Oncorhynchus mykissWalbaum,1792.

Salmo trutta L., 1758.

Hucho hucho Linnaeus, 1758.

Thymallus thymallus Linnaeus, 1758.

Abramis sapa Pallas, 1814.

Alburnoides bipuctatus Bloch, 1782.

Barbus meridionalis Risso,1828.

Chalcalburnus chalcoidesGueldenstaedt, 1772.

Ctenopharyngodon idellaValenciennes, 1844.

Gobio kesslerii Dybowski,1862.

Gobio uranoscopusAgassiz, 1828.

Hypophthalmichthys molitrixValenciennes, 1844.

Hypophthalmichthys nobilis

Petromyzonidae

Acipenseridae

Salmonidae

Thymallidae

Cyprinidae




Richardson, 1845.

Leuciscus leuciscus Linnaeus, 1758.

Pelecus cultratus Linnaeus, 1758.

Phoxinus phoxinus Linnaeus, 1758.

Vimba vimba Linnaeus, 1811.

Neogobius kessleri

Gunther, 1861.

Gymnocephalus schraetser

Linnaeus, 1758.

Zingel streber Siebold, 1863.

Zingel zingel Linnaeus, 1758.

Cottus gobio L., 1758.

)16. kleniæ ( )17. sabljarka ( )18. pijor ( )19. nosara ( )

20. keslerov glavoèiæ ()

21. prugasti balavac ()

22. mali vretenac ( )23. veliki vretenac ( )

24. peš ( )

Zbog takve brojnosti i stanja ribljih populacija u rijeciSavi i pritocima na ovom podruèju, vjeruje se da bi naširem podruèju Lonjskoga polja moglo �ivjeti i više od33 zabilje�ene vrste riba.

Zbog raznolikosti staništa koje ribe nastanjuju irazlièitog sastava ihtiofaune na njima, mogu serazluèiti tri osnovna tipa voda na podruèju PP Lonjskopolje:

1. mrtvaje, bare, iskopi i druge zatvorene vodestajaæega tipa

2. kanali i stari tokovi rijeka kroz polje3. rijeka Sava.

U prvoj grupi voda zabilje�ene su tipièno limnofilnei neutrofilne vrste riba koje preferiraju staništastajaæih voda: sunèanica, babuška, somiæ, štuka,crvenperka, bodorka, linjak, karas, gavèica, èikov,vijun, grgeè

Sastav ihtiofaune u kanalima i starim tokovimaslièniji je fauni rijeke Save nego stajaæim staništima.Što je bolja povezanost kanala s rijekom i što je višivodostaj Save, to je fauna sliènija onoj u rijeci Savi ipoveæava se raznolikost zajednice riba. Pojavljaju sevrste tipiène za rijeèno korito: koselj, bolen, klen, jez,podust

Ihtiofauna rijeke Save puno je brojnija od one usamom Lonjskom polju, pa Sava slu�i kao izvorraznolikosti pojedinih reofilnih i neutrofilnih vrsta ribakoje nastavaju poplavno podruèje Lonjskoga poljakao privremeno stanište.

U ulovu od trideset i tri vrste riba najzastupljenije suuklija (24,7%), sunèanica (10,5%), bodorka (12,3%),

Gobidae

Percidae

Cottidae

1)

2)

3)

Richardson, 1845.

Leuciscus leuciscus Linnaeus,1758.

Pelecus cultratus Linnaeus, 1758.

Phoxinus phoxinusLinnaeus, 1758.

Vimba vimba Linnaeus, 1811.

)16. common dace (

)17. ziehe ( )18. common minnow (

)19. vimba ( )

20. big head goby (Neogobius kessleri Gunther,1861.)

21. striped ruffe (Gymnocephalus schraetserLinnaeus, 1758.)

22. streber (Zingel streber Siebold, 1863.)23. zingel (Zingel zingel Linnaeus, 1758.)

24. common bullhead (Cottus gobio L., 1758.)Because of this kind of abundance and the situationof the fish populations in the Sava River and in thetributaries in the area, it is believed that in the widerLonjsko Polje area there might be more than the 33recorded species living.

Because of the diversity of the habitats the fishinhabit and the diverse composition of theichthyofauna in them, three basic types of water inthe area of Lonjsko Polje Nature Park can bedistinguished:

1. oxbows, ponds, excavations and other enclosedwater of the standing type

2. branches and old courses of rivers through thecommon

3. the Sava River.

Gobidae

Percidae

Cottidae

1)

2)

3)

In the first group, typical limnophilous andneutrophilous species of fish have been observed, fishthat prefer standing water habitats: pumpkin-seed,Prussian carp, black bullhead, pike, common rudd,common roach, tench, Crucian carp, bitterling, weatherloach, Danubian loach and European perch

The composition of the ichthyofauna in the channelsand old river courses is more similar to the Sava faunathan to that of the standing water. The better theconnection of the channels with the river, and the higherthe Sava water level, the more similar the fauna is to theSava fauna, and the greater the diversity of the fishcommunity. Species typical of the river course appear:blue bream, asp, chub, ide, common nase

The ichthyofauna of the Sava River is much morenumerous than the ichthyofauna in Lonjsko Polje itself,and the Sava thus serves as a source of diversity for someof the rheophilous and neutrophilous species of fish thatinhabit the floodplain area of Lonsjko Polje as a temporaryhabitat.



21

crvenperka (7,9%) i babuška (5,7%) (tablica 3.).Meðu najbrojnije vrste svakako pripada i patuljastisomiæ, iako nije uziman u velikom broju za labora-torijsku obradu. U relativnim odnosima brojnostislijede deverika, krupatica, štuka i grgeè. Ni brojnostštuke naoko nije velika, ali to je posljedica namjerneselektivnosti prilikom uzorkovanja. Štuka je naimeosjetljivija na djelovanje elektroagregata (posebnomlade jedinke), pa veæina ulovljenih štuka nijevaðena iz vode, a i one uzete za uzorkovanje vraæenesu u vodu. Zato pretpostavljena brojnost nije jednakarezultatima obraðenih riba. Pretpostavlja se da serelativna brojnost pojedinih vrsta kreæe ovako: uklija(~33%), sunèanica (~20%), babuška (~10-15%). Napojedinim staništima odreðene su vrste dominantne iprevladavaju brojnošæu. Zabrinjavajuæe je velikabrojnost unesenih vrsta, sunèanice, patuljastogsomiæa i babuške, u mrtvajama i iskopima u polju gdjesu to najèešæe dominantne vrste. Udio ribagrabljivica, smuða, štuke, soma i grgeèa, u Lonjskomje polju od 10 do 15%. U ulovu grabljivicaprevladavaju štuka i grgeè.

U relativnim odnosima ihtiomase (tablica 4.) prevla-davaju babuška (25%), štuka (18%), bodorka (6,4%),deverika (5%), sunèanica (4,3%) i patuljasti somiæ(3,4%). Som (13%) i smuð (4,4%) imaju naoko velikuihtiomasu, ali to je posljedica ulova nekoliko velikihjedinka (som 12 kg i smuðevi od 2 do 3 kg) napojedinaènim lokalitetima. Osamnaest vrsta se javljas ihtiomasom manjom od 1%.

Ihtiomase po hektaru proraèunate iz prirasta kreæu seod 30 do 90 kg. Izraèunata brojnost jedinka je od2000 do 4000 riba po hektaru.

Postoje razlike u brojnosti i sastavu vrsta riba izmeðuvoda u samom Lonjskom polju i rijeci Savi. Uzpojedine vrste koje se podjednako pojavljuju, poputuklije, bodorke, grgeèa i koselja, pojedine vrste ribasu dominantnije ili èešæe na odreðenom tipu staništa.Tako su u samom polju brojnije i èešæe limnofilne ineke neutrofilne vrste, poput sunèanice, crvenperke,babuške, štuke, patuljastog somiæa, karasa i linjaka,dok se u Savi javljaju rjeðe ili samo sporadièno. Zarijeku Savu dominantne su i èešæe vrste poputkrupatice, balavca, mrene, klena, jeza, manjiæa,podusta i vijunice. Meðu ribe Lonjskoga poljauvrštene su i ribe ulovljene u kanalu Trebe� kojiprema ihtiofauni vrlo slièi rijeci Savi, što zbog izravneveze ovih dvaju tokova, što zbog staništa koja Trebe�pru�a ribljim zajednicama.

In the catch of thirty-three species of fish, the mostnumerous were the common bleak (24,7%),pumpkinseed (10,5%), common roach (12,3%), commonrudd (7,9%) and Prussian carp (5,7%) (Table 3). Thebrown bullhead certainly belongs among the mostnumerous species too, although it was not taken in largenumbers for laboratory treatment. In relative ratios ofabundance then come the common bream, silver bream,pike and European perch. The abundance of the pikealso does not seem to be very great, but this is theconsequence of the deliberate selectivity exercisedduring sampling. The pike is very sensitive to the effect ofthe generator (particularly young individuals) and most ofthe pike caught were not taken from the water, whilethose taken for sampling were put back. Thus theassumed abundance is not the same as the results of thefish processed. It can be assumed that the relativeabundance of individual species ranges as follows:common bleak (~33%), pumpkinseed (~20%), Prussiancarp (~10-15%). In individual habitats certain species aredominant and dominate in terms of numbers. The largenumbers of introduced species, the pumpkinseed, brownbullhead and Prussian carp, in the oxbows and pits in thecommon, where they are most commonly the dominantspecies, give grounds for concern. The proportion ofpredatory fish in Lonjsko Polje, of pike-perch, pike,sheatfish and European perch, is from 10 to 15%. Thepike and European perch predominate in the catch ofpredators.

Table 4 shows the relative ratios of ichthyomass: thePrussian carp (25%), pike (18%), common roach (6,4 %),common bream (5%), pumpkinseed (4,3%) and brownbullhead (3,4%) are dominant. The sheatfish (13%) andpike-perch (4.4%) would seem to have a largeichthyomass, but this is actually the consequence of thecatch of a few very large individuals (a catfish of 12 kg andseveral pike-perch of 2 to 3 kg) in certain places. Eighteenspecies appeared with an ichthyomass of less than 1%.

The ichthyomass per hectare calculated from theincrement ranges from 30 to 90 kg. The calculatedabundance of individuals is about 2000 to 4000 fish perhectare.

There are differences in the abundance and compositionof fish between the waters in Lonjsko Polje itself and inthe Sava River. Alongside the individual fish that appearequally, like the bleak, common roach, European perchand blue bream, some fish are distinctly more dominantor more frequent in a given type of habitat. Thus inLonjsko Polje itself the limnophilous and someneutrophilous species are more dominant, including thepumpkinseed, rudd, Prussian carp, pike, black bullhead,Crucian carp and tench, while in the Sava River theseappear less frequently or indeed sporadically. In theSava, species such as the silver bream, ruffe, barbel,chub, ide, burbot, common nase and Balkan loach aremore frequent and dominant. Fish classified as LonjskoPolje species include those caught in Trebe� Channel,which according to its ichthyofauna, is very similar to theSava, because of the direct link between the twostreams, and also because of the habitats that theTrebe� affords the fish communities.




Tablica 1. Rasprostranjenost pojedinih vrsta ribaPP Lonjskoga polja na razlièitim lokalitetima

Table 1. Distribution of species of fish of LonjskoPolje Nature Park in different localities.

*1 - Èigoæ iskop; 2 - Èigoæ privremena voda; 3 - Èigoæmrtvaja; 4 - Mu�ilovèica iskop; 5 - Mu�ilovèica privremenavoda; 6 - Mu�ilovèica mrtvaja; 7 - Suvoj mrtvaja; 8 - Trebe�kanal; 9 - Trebe� mrtvaja; 10 - Trebe� stari tok; 11 - Puskamrtvaja zapadno; 12 - Puska mrtvaja istoèno; 13 - Strugkanal; 14 - Veliki Strug; 15 - Mokro polje; 16 - Stara Lonja; 17Košutarica mrtvaja; 18 - Mlaka mrtvaja; 19 - Višnjicamrtvaja; 20 - Sava Jasenovac; 21 - Sava Trebe�; 22 - SavaBobovac

*1 - Èigoæ excavation; 2 -Èigoæ temporary pool; 3 - Èigoæoxbow; 4 - Mu�ilovèica excavation; 5 - Mu�ilovèicatemporary pool; 6 Mu�ilovèica oxbow; 7 - Suvoj oxbow; 8 -Trebe� channel; 9 - Trebe� oxbow; 10 - Trebe� old stream;11 Puskax oxbow west; 12 - Puska oxbow east; 13 - Strugchannel; 14 - Veliki Strug; 15 - Mokro polje; 16 - StaraLonja; 17 Košutarica oxbow; 18 - Mlaka oxbow; 19 -Višnjica oxbow; 20 - Sava Jasenovac; 21 - Sava Trebe�; 22- Sava Bobovac



23

Tablica 2. Brojnost ulovljenih riba na podruèju PP

Lonjsko polje po vrstama

Table 2. Abundance of fish caught in the area of

Lonjsko Polje Nature Park according to species




Tablica 3. Ihtiomasa pojedinih vrsta riba u PPLonjsko polje prema ulovima na 22 lovne postaje

Table 3. Ichthyomass of individual species of fishin Lonjsko Polje Nature Park according tocatches at 22 catching stations



25

Rijetke vrste

Od 33 zabilje�ene vrste riba njih èetiri, iz razlièitihrazloga, mo�emo ubrojiti u rijetke. Neke od njihunesene su u ovaj sustav namjerno ili sluèajno, aneke su pripadnici autohtone faune. U PP Lonjskopolje rijetkim vrstama smatraju se crnka, belica,bezribica i pastrvski grgeè. Crnka i belica su izrazitolimnofilne ribe koje se pojavljuju na toèno odreðenimstaništima i najèešæe su toèkaste rasprostranjenosti.Bezribica i pastrvski grgeè su alohtone vrste pa jenjihova malobrojnost prihvatljiva i dobrodošla.

Rijetkim vrstama mo�emo smatrati i neke od onihkoje su navedene kao prisutne u rijeci Savi na ovompodruèju, ali koje nisu ulovljene. Vjerojatno je i malabrojnost populacija jedan od razloga zašto nisuulovljene pri ovim istra�ivanjima. Primjeri takvih vrstakojima se populacije u rijeci Savi smanjuju i nisuzabilje�ene prilikom naših uzorkovanja bili bi:dunavska paklara ( ), keèiga( ), mladica ( ), velikapliska ( ), sabljarka( ), keslerov glavoèiæ (

), prugasti balavac () i mali vretenac ( ).

Eudontomyzon danfordi

Acipenser ruthenus Hucho hucho

Chalcalburnus chalcoides

Pelecus cultratus Neogobius

kessleri Gymnocephalus

schraetser Zingel streber

Rare species

Of the 33 species of fish recorded, four of them, forvarious reasons, can be counted as rare. Some ofthem were introduced into the system deliberately orfortuitously, and some are members of theindigenous fauna. In Lonjsko Polje Nature Park theEuropean mudminnow, sunbleak, false harlequinand largemouth bass are considered to be rarespecies. The European mudminnow and sunbleakare markedly limnophilous fish that occur in preciselydefined habitats and most often have a dotteddistribution. The false harlequin and largemouthbass are allochthonous species and so their smallabundance is acceptable and welcome.

Some of those that are quoted as present in the SavaRiver in this region but nevertheless were not caughtcan also be considered, we think, rare species.Probably the small numbers of the populations is oneof the reasons why they were not caught duringthese investigations. Examples of such species thepopulations of which in the Sava River are falling andwere not recorded during our sampling are:Danubian lamprey ( ), sterlet( ), huchen ( ),Danubian bleak ( ), ziehe( ), big head goby (

), striped ruffe ( )and streber ( ).

Eudontomyzon danfordiAcipenser ruthenus Hucho hucho

Chalcalburnus chalcoidesPelecus cultratus Neogobius

kessleri Gymnocephalus schraetserZingel streber




3. STATUS UGRO�ENOSTI

Opæenito govoreæi, najugro�enijim ekološkimsustavima Hrvatske pokazale su se plitke slatke vodei moèvare. U zajednici riba takvih staništa brojne suvrste ugro�ene, a dio ih je s njih i nestao. Na tezajednice riba utjeèu brojni èimbenici. Meðu njimaprednjaèe oneèišæenja rijeka, melioracije i regulacijevodotoka, unos alohtonih vrsta, goleme potrebemodernoga èovjeka za tehnièkom i pitkom vodom,prelov i turizam. Pritom su naroèito u opasnosti rijetkei osjetljive vrste.

Sedam vrsta riba širega podruèja, èija je prisutnostpotvrðena ili se pretpostavlja za PP Lonjsko polje,endemi su dunavskoga slijeva. To su crnka (

), mladica ( ), veliki vijun (), tankorepa krkuša ( ),

plot ica ( ), prugasti balavac( ) i mali vretenac (

).

Nestale vrste u rijeci Savi su pojedine vrste jesetrakoje su u prošlosti nastanjavale to podruèje, posebnoobièna moruna ( ) i pastruga (

), ali i sim ( ), obiènajesetra ( ) te crnomorskaharinga ( ). Sim se smatra izumrlomvrstom u èitavom dunavskom slijevu. S obzirom na toda ne postoje prijašnji podaci o rasprostranjenosticrnke ( ) i belice (

) na ovom podruèju, a tijekom ovihistra�ivanja nisu naðene, teško je tvrditi da su nestales ovog podruèja, ali pretpostavka je da su bile širerasprostranjene i zastupljene brojnijim populacijama.Prugasti balavac je gotovo nestao iz rijeke Save izadnjih godina nisu ga zabilje�ili znanstvenici, iakošportsko-rekreativni ribolovci povremeno javljaju onjegovu ulovu.

Prema IUCN kategorizaciji ugro�enosti, svojte semogu podijeliti na osam kategorija. Na podruèjuEurope u skupinu od ranjive do kritièno ugro�enesvojte ubrajaju se crnka ( ) i autohtonirijeèni šaran ( ). Od riba koje nisu

3.1. Endemi

3.2. Nestale vrste

3.3 Ugro�ene vrste

Umbra

krameri Hucho hucho Cobitis

elongata Gobio uranoscopus

Ruti lus pigus

Gymnocephalus schraetzer Zingel

streber

Huso huso Acipenser

stellatus Acipenser nudiventris

Acipenser güldenstädti

Alosa pontica

Umbra kramerii Leucaspius

delineatus

Umbra krameri

Cyprinus carpio

3. STATUS OF ENDANGERMENT

Speaking in general, the most endangeredecosystems in Croatia have proved to be shallowfreshwater areas and wetlands. In the fish communityof such habitats, many species are endangered, andsome of them have disappeared. Many factors affectthese fish communities. In the lead among suchfactors are river pollution, the engineering andstraightening of the streams, the introduction offoreign species, the enormous needs ofcontemporary human beings for process and drinkingwater, over-fishing and tourism. And it is the rare andsensitive species that are particularly in danger.

Seven fish species of the wider area, the presence ofwhich in Lonjsko Polje Nature Park has been eitherconfirmed or can be reasonably supposed arespecies endemic to the Danube basin. They are: theEuropean mudminnow ( ), huchen( ), Balkan loach ( ),Danubian gudgeon ( ), Dalmatianroach ( ), striped ruffe (

) and streber ( ).

The vanished species in the Sava River areindividual species of sturgeon that did inhabit thearea in the past, particularly the Beluga sturgeon( ) and stellate sturgeon (

), as well as the ship sturgeon (), the Russian sturgeon () and the Pontic shad ( ).

The ship sturgeon is considered a species that isextinct in the whole of the Danube basin. Since thereare no data concerning the previous distribution ofthe European mudminnow ( ) andsunbleak ( ) in this region, andduring the investigation they were not found, it is hardto claim that they have vanished from the region, butit can reasonably be assumed that they were oncemore widely distributed and represented by morenumerous populations. The striped ruffe has almostvanished from the Sava River and in the last fewyears no scientists have reported it, although anglershave occasionally reported catching it.

According to the IUCN categorisation of threat level,taxa can be divided into eight categories. In Europe,

3.1. Endemic species

3.2. Vanished species

3.3. Endangered species

Umbra krameriHucho hucho Cobitis elongata

Gobio uranoscopusRutilus pigus Gymnocephalus

schraetzer Zingel streber

Huso huso Acipenserstellatus Acipensernudiventris Acipensergüldenstädti Alosa pontica

Umbra krameriiLeucaspius delineatus



27

ulovljene, ali èiji se dolazak oèekuje, na popisu su imladica ( ), keèiga ( )te mali vretenac ( ). Prema Crvenojknjizi riba Hrvatske (u tisku), na popisu od osjetljivihdo kritièno ugro�enih (VU-CR) 12 je vrsta riba koje�ive na podruèju PP Lonjsko polje. Uzevši u obzir iostale ribe, pretpostavljene za šire podruèje, ovaj brojdose�e 22 vrste.

Najugro�enije svojte su mladica (za dunavski slijevkritièno ugro�ena), crnka i divlji (rijeèni) šaran, doksu posebno osjetljive mali i veliki vretenac te keèiga.Gledajuæi samo Lonjsko polje, ugro�ene svojte bilebi tipiène limnofilne vrste: crnka, belica, èikov, linjak ikaras zbog gubitka i smanjivanja staništa,kompeticije invazivnih vrsta i promjene poplavnogritma. Dvoprugasta uklija, koja se smatraugro�enom vrstom dunavskoga slijeva, u ovomistra�ivanju nije zabilje�ena, iako su njezinepopulacije u Savi, na pojedinim brzotekuæimstaništima, prilièno brojne.

Za sada u Hrvatskoj nema zaštiæenih vrsta riba. Takoni na podruèju parka prirode nema posebnozaštiæenih vrsta. Za gospodarskih 12 vrsta prema"Zakonu o slatkovodnom ribarstvu" postoji pravilnik olovostaju. Dvanaest vrsta je na popisu Bernskekonvencije (aneks 2 i 3) i ima odreðenu zaštitu uEuropi (tablica 4.), dok je 6 vrsta na popisu HabitatDirective. Uzmemo li u obzir i one vrste èiji se dolazaksamo pretpostavlja, onda su ti brojevi veæi: Bern 27 iHD 17 vrsta. Na popisu obiju ovih konvencija nalazese sljedeæe vrste: vijun, piškur, bjeloperajna krkuša,gavèica, plotica, ali i keèiga, mladica, lipljen, potoènamrena, velika pliska, tankorepa krkuša, blistavac,mali i veliki vretenac. Prema Bonnskoj konvenciji ozaštiti migratornih vrsta divljih �ivotinja, zaštiæene susve jesetre pa i keèiga koja se ovdje pojavljuje.

Hucho hucho Acipenser ruthenus

Zingel streber

3.4. Zaštiæene vrste

the European mudminnow ( ) and theautochthonous Cyprinus carpio belong to thevulnerable-critically endangered group. Of the fishthat were not caught, that can be assumed to come,also on the list are the huchen ( ), sterlet( ) and the streber (

).According to the Red Book of Fish in Croatia(in the press), 12 species of fish that live in the area ofthe Lonjsko Polje Nature Park are on the list ofvulnerable to critically endangered (VU-CR). Takingthe other fish into account assumed for the widerarea, this number comes to as many as 22 species.The most endangered taxa are the huchen (criticallyendangered for the Danube basin), the Europeanmudminnow and the wild common carp, while thestreber and the zingel and the sterlet are particularlysensitive. Looking at Lonjsko Polje only, theendangered species would be the typicallimnophilous species: the European mudminnow,sunbleak, tench and Crucian carp because of lossand reduction of habitats, the competition frominvasive species and changes in the rhythm offloods. The schneider, which is considered anendangered species in the Danube basin, was notrecorded in this investigation, although itspopulations in the Sava, in certain fast-waterhabitats, are fairly numerous.

In Croatia so far there are no protected fish species.Thus also in the nature park there are no speciallyprotected species. For the twelve commerciallyimportant species, according to the FreshwaterFishing Law, there are regulations concerning aclose season. Twelve species are on the BerneConvention list (Annex 2 and 3) and do have acertain amount of protection in Europe (Table 4),while six species are on the list of the HabitatDirective. If we take into account those species thatare only assumed to come, then the numbers will begreater: Berne 27 and HD 17 species. On the list ofboth of these conventions the following species arefound: Danubian loach, weather loach, whitefingudgeon, bitterling, Dalmatian roach, but also thesterlet, huchen, grayling, southern barbel, Danubianbleak, Danubian gudgeon, blageon, streber andzingel. According to the Bonn Conventionconcerning the protection of migratory species ofwild animals, all the sturgeon as well as the sterletthat can be found here are protected.

Umbra krameri

Hucho huchoAcipenser ruthenus Zingel

streber

3.4. Protected species




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Map 1.

Predlo�eni sustav športskog i tadicionalnog ribolova u parku prirode Lonjskopolje. Izvor: Prijedlog Prostornog plana podruèja posebnih obilje�ja Park prirodeLonjsko polje. Izradio: �upanijski ured za prostorno ureðenje i zaštitu okoliša,Sisak.

The proposed angling and traditional fishery system for Lonjsko Polje NaturePark. Source: Draft Physical Plan for Lonjsko Polje Nature Park. Produced by:County Office for Physical Planning and Environmental Protection, Sisak.

PRIJEDLOG UREÐENJA RIBARSTVAU PROSTORNOM PLANU PARKA PRIRODELONJSKO POLJE

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4.EKOLOŠKE ZNAÈAJKE RIBLJIHZAJEDNICA

4.1 Odabir staništa i sklonost premabrzini toka

Vrste su rasporeðene u grupacije prema zadr�avanjuu odreðenoj zoni brzine protoka i prema tipu staništakoje nastanjuju tijekom �ivota. Prema brzini protokavode razlikujemo litofilne (lentièke), neutrofilne ireofilne (lotièke) vrste riba. Od 33 zabilje�ene vrste uPP Lonjsko polje, 6 vrsta (uz njih limnofilne su i jošneregistrirane crnka i belica) je limnofilno, tj.stanovnici su stajaæih voda; 10 vrsta je reofilno, tj.stanovnici su tekuæih voda. Svih ostalih 17 vrstapripada skupini neutrofilnih (eurytopic) koji sesmatraju generalistima s obzirom na izbor stanište.

Prema tome koliko se èesto pojavljuju na poplavnimpodruèjima PP Lonjsko polje vrste mo�emo podijelitina stalne, povremene i sluèajne vrste.

Staništa mrtvaja, ritova i rukavaca, manje ili višepovezanih s rijekom, imaju vrlo va�nu ulogu uoèuvanju populacija pojedinih zajednica riba.Zajednicu riba koja stalno nastanjuje poplavne zonei moèvarna staništa èine karas (

), linjak ( ), crvenperka( ), èikov (

), crnka ( ) i belica (). Tu skupinu riba naziva se limnofilne

vrste ili "crna riba". Za �ivot tih vrsta va�ne sunaplavne bare, depresije i nepovezani kanali, èestoodvojeni od glavne rijeke. Regulacije rijeka u praksiuklanjaju hidrološki i geomorfološki dinamizam, teodvajaju rijeku od naplavne zone. U prošlosti, prijeureðenja korita Save, takva poplavna podruèja bilasu brojna, a danas su gotovo nestala iz njezinaporjeèja. Kako spomenutih jedinka tih vrsta danasima vrlo malo, o njihovoj prijašnjoj rasprostranjenostine znamo mnogo. Ta je zajednica riba u Europiopasno ugro�ena i, premda nema ekonomskuvrijednost, za biološku je raznolikost od posebnogaznaèenja. Linjak i crvenperka, kao fitofili izrazitovezani uz vodenu vegetaciju naplavnih zona, unaèelu su manje ugro�eni od ostalih vrsta tezajednice.

Unatoè tome što prema sklonosti brzini protokapripadaju skupini neutrofila, još jedna skupina riba jevrlo èesta na takvu tipu staništa. To su štuka (

Stalne vrste

Carassius

carassius Tinca tinca

Scardinius erythrophthalmus Misgurnus

fosilis Umbra krameri Leucaspius

delineatus

Esox

4. ECOLOGICALCHARACTERISTICS OF THE FISHCOMMUNITIES

4.1. Selection of habitat and liking forcurrent velocity

Species can be classified into groups according towhether they stay in a given area of current velocityand according to the type of habitat that they inhabitduring their lifetimes. According to water velocity wecan distinguish lithophilous (lentic), neutrophilous andrheophilous (lotic) species of fish. Of the 33 speciesrecorded in Lonjsko Polje Nature Park, six species (aswell as them, the unrecorded European mudminnowand sunbleak are limnophilous) are limnophilous, i.e.,live in standing water. Ten species are rheophilous,i.e., inhabit running water. All the other 17 speciesbelong to the neutrophilous or eurytopic group, whichare generalists with respect to their choice of habitat.

According to how often they appear in the floodplain ofLonjsko Polje Nature Park, we can distinguish speciesas residential, occasional and adventitious species.

The habitats of the oxbows, marshes and channelsmore or less linked with the river have a veryimportant role in the preservation of populations ofindividual fish communities. A community of fish thatis permanently resident in the inundated zones andthe wetland habitats is constituted by the Cruciancarp ( ), tench ( ),common rudd ( ),weather loach ( ), Europeanmudminnow ( ) and sunbleak( ). This group consists oflimnophilous species or “black fish”. The alluvialponds, depressions and unconnected channelsoften detached from the main river are important forthe lives of these species. Straightening of the riversin practice takes away their hydrological andgeomorphologic dynamism, and separates the riverfrom the alluvial zone. In the past, before the courseof the Sava was straightened, such alluvial areaswere very numerous, although today they have moreor less vanished from the basin. Since there are veryfew individuals of these species today, we do notknow much of their previous distribution. This fishcommunity is critically endangered in Europe and,although it has not economic value, it is of particularimportance for biological diversity. The tench and thecommon rudd, which are phytophilous speciesparticularly connected with the water plans of theflood zones, in principle they are less endangeredthan the other species of this community.

Resident species

Carassius carassius Tinca tincaScardinius erythrophthalmusMisgurnus fosilis

Umbra krameriLeucaspius delineatus



29

lucius Carassius gibelio

Alburnus alburnus Perca fluviatilis

Silurus glanis Rutilus rutilus

Lepomis gibbosus

Ameiurus nebulosus

Cyprinus carpio Stizostedion

lucioperca Abramis brama

Abramis balerus Abramis bjoerkna

Rhodeus se r i ceus

Gymnocephalus cernuus

Chondrostoma

nasus

Leuciscus idus

Barbus barbus Lota lota Rutilus

pigus Leicuscus leuciscus

Alburnoides

bipunctatus Leuciscus leuciscus

Vimba vimba Abramis sapa

Acipenser ruthenus

Gymnocephalus schraetser Zingel

streber

), babuška ( ), uklija( ), grgeè ( ), som( ) te bodorka ( ).Zabrinjavajuæe je što su na podruèju PP Lonjskopolje na veæini takvih staništa ipak brojnošæupremoæne dvije alohtone sjevernoamerièke vrste:sunèanica ( ) i patuljasti somiæ( ).

Zajednicu povremenih korisnika naplavne zone,odnosno rijeènih riba koje su naèinom �ivota upojedinim sezonama vezane uz poplavne i plitkelitoralne zone èini sedam vrsta. U ovoj zajednicidolaze: šaran ( ), smuð (

), deverika ( ), koselj( ), krupatica ( ),gavè i ca ( ) i ba lavac( ). To su vrste kojenazivamo neutrofilne, tzv. "siva riba", a nalazimo ihjednako u stajaæim i tekuæim vodama. Sasmanjenjem poplavnih podruèja, na posredan naèin,i ova je skupina riba pod sve veæim ljudskim utjecajemuz smanjenje brojnosti populacija.

Meðu povremene korisnike poplavne nizine ubrajase i jedna reofilna vrsta, podust (

). Ta holobiontska migratorna vrsta jenajbrojnija riba prirodnoga korita rijeke. Populacijepodusta u Europi se smanjuju i sve su više ugro�enedjelovanjem èovjeka.

Neke vrste mogu se smatrati sluèajnima, s obziromna to da najèešæe nastanjuju druge tipove staništa.Pripadaju im sve vrste matice koje rijetko napuštajurijeku, primjerice, jez ( ), mrena( ), manjiæ ( ), plotica (

) i klen ( ). Te vrste više volestaništa s br�om tekuæom vodom bogatom kisikom, apripadaju grupi reofilnih vrsta ili tzv. "bijeloj ribi". Priistra�ivanju nisu naðene neke ribe koje pripadajuovoj skupini, a realno ih je oèekivati u ovom dijelurijeke Save. To su dvoprugasta uklija (

), kleniæ ( ), nosara( ), crnooka deverika ( ),keèiga ( ), prugasti balavac( ) i mali vretenac (

). Zadnje dvije vrste veæ du�e vrijeme nisunaðene u Savi, a zna se i da je prugasti balavac èešæiu Dunavu. Zbog utjecaja rijeke Une i njezineihtiofaune mogu se oèekivati i neke reofilne

Povremene vrste

Sluèajne vrste

Although according to their liking for flow velocitythey belong to the neutrophilous group, one othergroup of fish is very common in this type of habitat.This is composed of the pike( ), Prussiancarp ( ), common bleak (

), European perch ( ),sheatfish or catfish ( ) and the commonroach ( ). It is worrying that in the area ofLonjsko Polje Nature Park in most of such habitats,two allochthonous North American species aredominant in terms of numbers: the pumpkinseed( ) and the brown bullhead( ).

The community of occasional users of the floodzone, that is, of the river fish that, in their manner oflife in given seasons are connected with the floodedarea and the shallow littoral zone, consists of sevenspecies. In this community there are the commoncarp ( ), pike-perch (

), common bream ( ), bluebream ( ), silver bream (

), bitterling ( ) and the ruffe( ). These are species thatare called neutrophilous, the so-called grey fish, andthey can be found equally in stagnant and in runningwater. With the reduction of the flood areas, in anindirect way, this group of fish is increasinglybecoming subject to human influence, with areduction of numbers of populations.

Among the occasional users of the inundatedlowlands there is one rheophilous species, thecommon nase ( ). Thisholobiontic migratory species is the most numerousfish of the natural course of the river. The commonnase populations in Europe are reducing and areincreasingly endangered thanks to human activities.

Some species can be considered adventitious in thatthey most often inhabit other types of habitat. Allspecies of the mainstream, which seldom leave theriver, can be considered to belong to this type, forexample the, ide ( ), barbel (B

), burbot ( ), Dalmatian roach () and chub ( ). These

species are fonder of habitats with fast running waterrich in oxygen, and they belong to the group ofrheophilous species, the so-called “white fish”.During our investigation, some fish belonging to thisgroup were not found, fish that could realistically beexpected in this part of the Sava River. These are theschneider ( ), common dace( ), vimba ( ),Danubian bream ( ), sterlet (

), str iped ruffe (

Esox luciusCarassius gibelio Alburnus

alburnus Perca fluviatilisSilurus glanis

Rutilus rutilus

Lepomis gibbosusAmeiurus nebulosus

Cyprinus carpio Stizostedionlucioperca Abramis brama

Abramis balerus Abramisbjoerkna Rhodeus sericeusGymnocephalus cernuus

Chondrostoma nasus

Leuciscus idus arbusbarbus Lota lota Rutiluspigus Leicuscus leuciscus

Alburnoides bipunctatusLeuciscus leuciscus Vimba vimba

Abramis sapa Acipenserruthenus Gymnocephalus

Occasional species

Adventitious species




salmonidne vrste, poput mladice, potoène pastrve,kalifornijske pastrve, lipljena, peša i dr.

Zajednicu riba ovoga podruèja mo�emo podijeliti iprema reproduktivnoj strategiji i supstratu na kojipola�u jaja, a koji ima veliku ulogu u opstanku vrsteprilikom promjena pojedinih èinitelja (Balon, 1975.,Balon, 1990.). Ribe se slu�e razlièitim strategijamakako bi reprodukcija bila što uspješnija. Veæina vrsta(25) ne èuva svoju ikru niti mlade, sedam vrsta èuva,a jedna vrsta skriva buduæe potomstvo. Premapodlozi, tj. supstratu neophodnom za odlaganje jaja,tu skupinu riba dijelimo na litofilne (3 vrsta), fitofilne(11 vrsta te crnka i belica), fitolitofilne (8 vrsta),psamofilne (2 vrste) te ostrakofilne, litopalgofilne ipolifile sa po jednom vrstom. Od onih riba koje èuvajupotomstvo mo�emo razluèiti one koje prave gijezdo(4 vrste) i one koje prièvršæuju ikru na odreðenestrukture èuvajuæi je (3 vrste uz dodatak crnke ibelice). Gavèica je jedina vrsta koja skriva ikru(ostrakofil), i to u slatkovodnu školjku.

Meðu nezabilje�enim vrstama riba prevladavajulitofili, što je takoðer jedna od odlika rijeènihihtiocenoza.

Zajednica riba Lonjskoga polja sastoji se od 10nespecijaliziranih omnivora (sve�dera) i oportunihvrsta bentivora (prehrana pridnenim organizmima)(14) piscivora (prehrana ribama) (7), planktivora(prehrana planktonom) (2) i invertivora (prehranabeskralje�njacima) (2).

Dobna struktura ispitivanih populacija posljedica jeutjecaja okoliša, antropogenih faktora, kolièine hranei cijeloga niza interspecijskih i intraspecijskih odnosau populaciji. Dobna struktura jedan je od najbitnijihelemenata cjelokupne populacije za procjenuihtiomase i produkcije po jedinici površine. Najèešæevrste zastupljene su zadovoljavajuæim rasponomgodišta. U veæine vrsta najbrojnije su jedinke godišta

4.2. Reproduktivne znaèajke i mrijesnastaništa

4.3. Prehrana

4.4. Dobna struktura

schraetser Zingel streber) and the streber ( ). The lasttwo species have not been found in the Sava for quitea long time, and it is known that the striped ruffe ismore frequent in the Danube. Because of the impactof the Una River and its ichthyofauna, some kind ofrheophilous salmonid species could be expected,such as the huchen, brown trout, rainbow trout,grayling, common bullhead and others.

We can divide the fish community of this areaaccording to their reproductive strategies and thesubstrate on which they lay their eggs, and which hasa great role in the survival of the species duringchanges of given factors (Balon, 1975., Balon, 1990.).Fish use various strategies to try to ensure as muchreproductive success as possible. Most species (25)do not guard their eggs or fry, seven species do guardthem, and one species conceals its future progeny.According to the base, or substrate necessary for thedeposition of the eggs, we can divide this group of fishinto lithophilous (3 species), phytophilous (11 speciesand the European mudminnow and sunbleak), phyto-lithophylous (8 species), psamophilous (2 species)and ostracophilous, lithopalgophilous andpolyphilous, one species of each. Of those fish thatprotect their young we can distinguish those thatmake nests (4 species) and those that fix the eggs togiven structures and watch over them (3 species, withthe addition of European mudminnow and sunbleak).The bitterling is the only species that hides its eggs(ostracophylous), in the freshwater mollusc.

Among the unrecorded species of fish, thelithophilous prevail, which is also one of the featuresof riverine ichthyocoenoses.

The Lonjsko Polje fish community consists of 10unspecialised omnivores and opportunist species ofbenthivores (bottom feeders) 14 piscivores, (7)planktivores (2) and invertivores (feeds oninvertebrates) (2).

The age structure of the populations investigated isthe consequence of environmental impact,anthropogenic factors, quantity of food and a wholesequence of inter- and intraspecies relations in thepopulation. The age structure is one of the mostessential elements of the overall population for theestimation of ichthyomass and production per unit ofarea. The most frequent species were found with asatisfactory range of years. In most species the most

4.2. Reproductive features andspawning habitats

4.3. Food

4.4.Age structure



31

0+, jednogodišnje i, nešto manje, dvogodišnjejedinke.

Ulovi vrlo mladih riba su relativno bogati, posebno uplitkim poplavljenim dijelovima podruèja. Najvišemlaði je zabilje�eno tijekom svibnja i lipnja u samompolju nakon mrijesta šarana i deverike. Ulovljeniprimjerci su starosti 0+ bodorke, uklije, šarana,babuške, jeza, grgeèa, smuða, kruptice, patuljastogsomiæa i sunèanice. Ulovi starijih starosnih kategorijasu rjeði pa je zabilje�eno samo nekoliko jedinkastarijih od šest godina, poput soma, šarana i bolena.

Znaèenje migracija u riba dugi niz godina nije bilovrjednovano. Otkriveno je da ribe imajutransverzalne i longitudinalne migracije te da bi bezmoguænosti migriranja u pojedina staništa ubrzodrastièno smanjile svoje populacije. Staništa laguna,ritova i rukavaca povezanih s glavnom rijekom imajuvrlo va�nu ulogu kao povremena staništa upopulacijama pojedinih zajednica riba. Na�alost,èovjek je dugogodišnjom regulacijom rijeka namnogima uklonio hidrološki i geomorfološkidinamizam, odvojio rijeku od naplavne zone i takougrozio brojne vrste. Neke ribe su zbog tih zahvatanaposljetku i izumrle.

Kod transverzalnih migracija zajednica riba, u kojojse pojavljuju linjak, crvenperka, èikov, karas i bjelica,ne mogu opstati bez naplavnih bara, depresija inepovezanih kanala, èesto odvojenih od glavnerijeke. Danas je poznato da je ta zajednica naplavnezone opasno ugro�ena.

U riba Lonjskoga polja razlikujemo nekoliko tipovamigracija. Dvadeset i jedna vrsta je stagnofilniholobionski migrant, osam vrsta su reofilniholobiontski migranti a osam vrsta stanarice.Anadromne migracije vezane su uz gotovo izumrlejesetre: morunu ( ) i pastrugu (A

). Migracije holobiontskih selica za ovajprostor su najva�nije. Sve rjeða keèiga (A

), klen ( ), podust( ), mrena ( ),nosara ( ), sabljarka ( ),manjiæ ( ), veliki vretenac ( ) i som( ) migriraju du� rijeènog toka i napoplavnu zonu.

4.5. Migratorne vrste

Huso huso cipenser

stellatus

cipenser

ruthenus Leuciscus cephalus

Chondrostoma nasus Barbus barbus

Vimba vimba Pelecus cultratus

Lota lota Zingel zingel

Silurus glanis

numerous were individuals of age groups 0+, oneyear, and, somewhat fewer, two year old individuals.Catches of very young fish were relatively rich,especially in the shallow flooded parts of the area.Most fry were recorded during May and June in thecommon (pasture) itself after spawning of commoncarp and common bream. Specimens caught of ageclass 0+ were the common roach, common bleak,common carp, Prussian carp, ide, European perch,pike-perch, silver bream, brown bullhead andpumpkinseed. Catches of older age categories wereolder, and only a few individuals older than six yearswere recorded, such as the sheatfish, common carpand asp.

The importance of migration in fish for many yearswas not considered of importance. It was discoveredhowever that fish have transversal and longitudinalmigrations, and without the opportunity of migratingto given habitats, their populations would soonbecome drastically reduced. Habitats of lagoons,marshes and channels linked with the main riverhave a very important role as temporary habitats inthe populations of individual fish communities. Alas,through many years of hydraulic engineering, peoplehave stripped many rivers of their hydrological andgeomorphologic dynamism, have separated the riverfrom the flood zone and thus endangered manyspecies. Because of these operations, some of thesefish have become extinct.

In the case of transversal migrations of fishcommunities, in which the tench, common rudd,weather loach, Crucian carp and sunbleak or belicafigure, they cannot survive without the flood pools,depressions and unconnected channels often splitoff from the main river. Today it is known that thiscommunity of the floodplain area is criticallyendangered.

Several types of migration can be distinguished in thefish of Lonjsko Polje. Twenty-one species arestagnophilous holobiontic migrants, eight species arerheophilous holobiontic migrants and eight speciesare non-migratory. Anadromous migrations arerelated to the almost extinct sturgeons: the huchen( ) and stellate sturgeon (

). Migrations of holobiontic migratory fish arethe most important for this area. The increasingly raresterlet ( ), chub (

), common nase ( ),barbel ( ), vimba ( ), ziehe( ), burbot ( ), zingel (

) and the sheatfish ( ) migratealong the course of the river and into the floodplain.

4.5. Migratory species

Huso huso Acipenserstellatus

Acipenser ruthenus Leuciscuscephalus Chondrostoma nasus

Barbus barbus Vimba vimbaPelecus cultratus Lota lota Zingel

zingel Silurus glanis




5. IHTIOPRODUKTIVNOST

Za razumijevanje funkcioniranja ekosustava trebapoznavati raznolikost �ivoga svijeta nekog podruèja,a potom gustoæu i brojnost populacija jer one nisuuvijek stalne. Kako su ribe va�an element biološkogiskorištavanja rijeka, za racionalno gospodarenjevodama nu�no je istra�iti mehanizme koji uzrokujupromjene u ribljim populacijama. Mnoge vrstepokazuju znatne fluktuacije, koje su uvjetovanerazlièitim prirodnim èimbenicima (biotièkim iabiotièkim), a mogu biti i va�an indikator promjena uokolini.

Ribe su, kao konzumenti, na razlièitim razinama utrofièkoj piramidi, pa je stoga njihova prisutnost uvodotocima va�na za ravnote�u u biocenozi. Brojprisutnih vrsta ovisi o raznolikosti staništa nekogapodruèja. Što je veæi broj vrsta, to su i slo�enijiprehrambeni odnosi meðu razlièitim èlanovimaprehrambenih lanaca te se tako stvara kompleksnaprehrambena mre�a. Stabilnost ekosustava ovisi onjegovoj slo�enosti; on je stabilniji što je slo�eniji.Ribe su, kao osnova u svim prehrambenim lancima,va�ne i za brojèano stanje svih ostalih skupinakralje�njaka. Nestanak neke kljuène vrste mijenjacijelu riblju zajednicu koja se stabilizira na nekoj novojrazini. I smanjenje prehrambene osnove imat æe zaposljedicu smanjenje svih ostalih skupina uprehrambenom lancu.

Osim o tim èimbenicima, proizvodnja riba uotvorenim vodama ovisi i o svjetlosti, kemizmu vodeuoèi mrijesta, za vrijema mrijesta i nakon mrijesta,kvantitativnom i kvalitativnom sastavu biljne i�ivotinjske proizvodnje kojima se ribe hrane(bogatstvu fito- i zooplanktona, bentoskih pridnenihorganizama, kao i mikroorganizama), stanjumatiènog fonda pojedinih ribljih vrsta, poplavama(velièini poplavljene zone i du�ini poplave),kvalitativnom sastavu zemljišta poplavljene zone usmislu pedoloških karakteristika, stupnja obraštajavegetacije i, naposljetku, utjecaju èovjeka na ritamrazmno�avanja.

Mehanizam produkcije riba u slatkim vodama, ukvantitativnom i kvalitativnom smislu, dakle, ovisi osljedeæim èimbenicima:

temperaturnom re�imu voda uoèi mrijesta i zavr i jeme mri jesta, prema najpovol jn i j imtemperaturama za vrste koje naseljavaju te vode;

vjerojatnosti pojave niskih temperatura, stvaranja ikretanja leda te trajanja zaleðenosti vodene

�

�

5. ICHTHYOPRODUCTIVENESS

For an understanding of the functioning of theecosystem it is necessary to know the diversity of theliving world of an area, and then the density andabundance of the populations, because they are notalways constant. Since fish are an important elementof the biological use of rivers, for a rationalmanagement of waters it is necessary to investigatethe mechanisms that bring about changes in the fishpopulations. Many species show considerablefluctuations, which are condition by various naturalfactors (biotic and abiotic) and they can be animportant indicator of environmental changes.

As consumers, fish occupy various levels in thetrophic pyramid, and thus their presences in streamsis important for the equilibrium in a biocoenosis. Thenumber of species present depends on the diversityof habitats of a given area. The greater the number ofspecies, the more complex the food relations amongthe various members of the food chain, a complexfood network being created. The stability of anecosystem depends on its complexity, the morecomplex it is, the more stable it will be.As the base ofall food chains, fish are important for the abundanceof all other groups of vertebrates. The absence ofsome key species will change the whole fishcommunity that will then stabilise at some new level.A reduction of the food base will have theconsequence of reducing all the other groups in thegood chain.

The production of fish in open waters depends, aswell as on these factors, on light, water chemistry justbefore spawning, during and after spawning, thequantitative and qualitative composition of plant andanimal production on which the fish feed (amplephytoplankton and zooplankton, benthic organismsand microorganisms), the state of the breeding stockof given fish species, floods (size of the flood zoneand the length of the flooding), the qualitycomposition of the land of a floodplain, with respectto pedological characteristics, the degree ofvegetation growth and finally the impact of people onthe rhythm of reproduction.

The mechanism of fish production in fresh water,thus, depends, quantitatively and qualitatively, onthe following factors:

the temperature regime of the water before, andduring spawning, according to the optimumtemperatures for the species that inhabit thewater;

the likelihood of the appearance of lowtemperatures, the creation and movement of iceand the duration the surface is iced over;

�

�



33

površine;

kemijskom stanju vode pred mrijest, za vrijememrijesta i nakon mrijesta;

kvantitativnom i kvalitativnom sastavu biljne i�ivotinjske produkcije, posebno planktona,bentosa (faune dna) i mikroorganizama kojima seribe hrane;

stanju matiènoga fonda pojedinih ribljih vrsta, tj.brojnosti i stanju ukupno raspolo�ivoga brojaspolno zrelih mu�jaka svake vrste riba togavodenog staništa

pojavi variranja vodostaja uoèi mrijesta, za vrijemei nakon mrijesta;

poplavama, velièini poplavljenih zona, tj. površinezemljišta u hektarima koje voda pokriva u uvjetimaminimalnog, srednjeg i maksimalnog vodostaja;

kvalitativnom sastavu zemljišta poplavljene zone usmislu njegovih pedoloških znaèajka, stupnjaobraštaja vegetacije i sl.;

utjecaju èovjeka (antropogeni faktor) na ritamrazmno�avanja u prirodi.

Kao prostor visoke biološke produkcije, Lonjsko poljeje najveæe prirodno mrijestilište riba na podruèjuPosavlja, posebno za fitofilne i fitolitofilne vrste ribaotvorenih supstrata. Vjeruje se da je poplavna zonaparka jedna od najva�nijih za repopulaciju ovogadijela crnomorskoga slijeva. Poplavna podruèjava�na su kao mrijestilišta, posebno za fitofile, a tamogdje nema poplavnih podruèja brojnost fitofila je vrlomala (Holèik i Bastl, 1976.; Holèik i sur., 1981.). Topodruèje ima funkciju izvora hrane koji se stalnoobnavlja te opskrbljuje i glavni tok rijeke. Ujedno slu�ii kao utoèište ribama koje borave u takvim staništimaili dolaze iz uzvodnih dijelova gdje nema poplavnihpodruèja (Holèik i Bastl, 1976.; Holèik i sur., 1981.).Zahvaljujuæi golemoj raznolikosti poplavnih staništa,broj ribljih vrsta relativno je velik. Posebno je izra�enagustoæa njihovih populacija, ekološka produkcija iulov, osobito u dijelovima rijeka koje granièe spoplavnim podruèjima.

Proces poveæane eutrofikacije prate znatnepromjene u strukturi riblje zajednice. U ranomoligotrofnom stadiju prevladavaju pastrvske vrste. Unašim vodama to je obièno potoèna pastrva (

). Poveæano optereæenje hranjivimtvarima i buduæe promjene u abiotièkom i biotièkomokolišu rezultiraju stupnjevitom zamjenom salmonidagrgeèkama koje su znaèajka mezotrofnih voda. U

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trutta m. fario

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the chemical state of the water before spawning,during and after spawning;

qualitative and quantitative composition of plantand animal production, particularly of plankton, ofthe benthos (bot tom fauna) and themicroorganisms on which the fish feed;

the condition of the breeding stock of theindividual fish species, i.e., the numbers andcondition of the total available number of sexuallymature males of each of the species of fish of thisaquatic habitat;

the appearance of variation of the water levelbefore, during and after spawning;

floods, the size of the flooded zone, i.e., area thatthe water covers in conditions of minimum, meanand maximum water level;

qualitative composition of the land of the floodzone in the sense of its pedological features,degree to which it is overgrowth with vegetationand so on;

anthropogenic impact on the rhythm ofreproduction in nature.

An area of high biological production, Lonjsko Poljeis the greatest natural spawning area in the Posavinaarea, in particularly for phytophilous and phyto-lithofilous species of fish of open substrates. It isbelieved that the flood zone of the park is one of themost important for the repopulation of this part of theBlack Sea basin. Flood areas are important asspawning grounds, particularly for phytophilousspecies, and where there are no flood regions, thereare very few phytophilous species (Holèik and Bastl,1976; Holèik et al., 1981.). This area has the functionof food source that is constantly renewed and alsosupplies the main course of the river. It also serves asa refuge for fish that live in such habitats or comefrom the upstream parts where there are not floodareas (Holèik and Bastl, 1976; Holèik et al., 1981).Thanks to the greater diversity of flood habitats, thenumber of fish species is fairly large. The density oftheir populations, ecological production and catch,particularly in the parts of the rivers that border on theflood zones, are particularly pronounced.

The process of increased eutrophication isaccompanied by marked changes in the structure ofthe fish community. In the early oligotrophic stagesalmonid species dominate. In Croatian water this isusually the brown trout ( ).Increased load of nutrients and future changes in theabiotic and biotic environment result in the gradualreplacement of salmonids with perches, which areindicators of mesotrophic waters. In European waters

Salmo trutta m. fario



europskim vodama (grgeè),(smuð) i

(balavac) obièno se poveæavaju u toj fazi. Ueutrofnoj fazi struktura riblje zajednice potpuno sepromijeni. Populacija grgeèki je potisnuta idominaciju preuzimaju šaranke. Meðu njimadeverika ( ), bodorka ( ),krupatica ( ) i babuška (

) èesto èine veæinu ihtiomase.

Ribe i na druge naèine odgovaraju na uznapredovalueutrofikaciju. Prvo se poveæa stopa rasta, a zatim,kad se dosegne odreðeni prag, naglo se smanji.Kolièina mlaða naglo opada, a promijene se i navikemriješæenja i hranjenja, dok ponekad nastupi i velikainvadiranost. Raspodjela riba takoðer se mijenja kaoodgovor na smanjenje koncentracije kisika,smanjenu prozirnost i poveæanu mutnoæu. Vrste seèesto pomièu iz hipolimniona u epilimnion i iz litoralneu pelagièku zonu. Promjena ribljih vrsta unutarzajednica povezana je s promjenama u velièini isazrijevanju vrsta: velike vrste koje dugo �ive ikasnije sazrijevaju postupno zamjenjuju male, kratko�ivuæe i rano sazrijevajuæe vrste. Takoðer, na tomputu zamjenjivanja ribljih vrsta, poèetna zajednicariba nespecijaliziranih omnivora zamijeni sekarnivorima, zooplanktonofagima dna i herbivornimvrstama koje se hrane perifitonom. Zatim nestajuzooplanktonofagi, vrste koje se hrane na dnu, tekarnivori. Na kraju preostaju jedino omnivori,primjerice, grgeè ( ) i karas (

). Razlog te sukcesije nije nedostatakhrane, nego manjak pogodnoga tla za mriješæenje. Uterminima reproduktivnih skupina, poèetnaoligotrofna faza obilje�ena je dominacijom litofila kojiskrivaju (zaklanjaju) leglo. Oni æe biti zamijenjeni slitofilima i litopelagofilima otvorene podloge. Sljedeæufazu obilje�ava dominacija pelagofila, fitolitofila ifitofila otvorene podloge.

Kondicijsko stanje riba je uz sastav ribljih vrsta injihove meðusobne odnose vrlo dobar pokazateljznaèajka pojedinoga staništa te izraz svih ekološkihèimbenika toga podruèja. Osim tih prirodnihèimbenika, vrlo va�nu ulogu za kondicijsko stanjeriba imaju i antropogeni utjecaji, izravni ili posredni.

Kondicijski èimbenici za veæinu èestih vrstaLonjskoga polja veæi su od istih èimbenika riba rijeke

Perca fluviatilis

Stizostedion llucioperca Gymnocephalus

cernuus

Abramis brama Rutilus rutilus

Blica bjoerkna Carasssius

auratus gibelio

Perca fluviatilis Carassius

carassius

5.1. Kondicijsko stanje ribljih zajednica

the (European perch),(pike-perch) and

(ruffe) usually dominate in this phase. In theeutrophic phase the structure of the fish communityhas changed completely. The perch population hasbeen expelled and carps take over the dominantposition. Among them the common bream (

), common roach ( ), silver bream( ) and the Prussian carp or gibel carp( ) often make up the majorpart of the ichthyomass.

Fish respond in other ways too to advancedeutrophication. First of all the rate of growthincreases, and then, when a certain threshold isreached, suddenly drops. The quantity of fry falls, andthe feeding and spawning habits changed, whilesometimes there is a great degree of invasiveness.The distribution of the fish also changes, as responseto the reduction of oxygen, reduced transparency andincreased turbidity. Species often move from thehypolimnion to the epilimnion and from the littoral tothe pelagic zone. Change in fish species within thecommunities is related with changes in the size andmaturation of species; the large species that live longand mature later gradually replace the small, short-lived and early maturing species. In addition, duringthe process of the replacement of the species, theinitial community of unspecialised omnivores isreplaced by carnivores, the zooplanktonphagousspecies of the bottom and the herbivore species thatf e e d o n t h e p e r i p h y t o n . T h e n t h ezooplanktonphages, the species that feed on thebottom, and the carnivores, vanish. At the end onlythe omnivores remain, for example the Europeanperch ( ) and the Crucian carp( ). The reason for thissuccession is not lack of food, rather shortage of bedsuitable for spawning. In the terms of the reproductivegroups, the initial oligotrophic phase is marked by thedomination of the lithophilous species that concealtheir eggs. They are replaced by the lithophiles andthe litho-pelagophiles of the open base. The nextphase is marked by the domination of pelagophiles,phyto-lithophiles and phytophiles of the open bed.

The condition factors of the fish are, along with thecomposition of fish species and their interrelations, avery good indicator of the features of a given habitatand an expression of all the ecological factors of thearea.Apart from these natural factors, anthropogenicimpacts, direct and indirect, have a very importantpart to play in the condition state of the fish.

The condition factors for most of the frequent

Perca fluviatilis Stizostedionllucioperca Gymnocephaluscernuus

Abramisbrama Rutilus rutilusBlica bjoerknaCarasssius auratus gibelio

Perca fluviatilisCarassius carassius

5.1. Fish community condition factors


35

Save, a u usporedbi s pojedinim literaturnimpodacima stranih autora uglavnom pokazuju i veæevrijednosti. Iznimku èine grgeè i bodorka èije suvrijednosti CF-a za rijeku Savu veæe negoli zaLonjsko polje, ali tome je mo�da razlog premali brojanaliziranih uzoraka iz Save. Ribe Lonjskoga poljaobièno pokazuju i br�i du�insko-maseni rast u mlaðojdobi, u usporedbi s onima iz rijeke Save. Prematome, mo�e se zakljuèiti da vode Lonjskoga poljaimaju veæu trofiènost i pru�aju bolju prehrambenuosnovicu za odrastanje i rast riba, tj. zaihtioprodukciju.

species of Lonjsko Polje are greater than the samefactors of the fish in the Sava River, and incomparison with some of the literature figures offoreign authors mainly show even greater values. Anexception is in the European perch and commonroach, the CF values of which for the Sava River aregreater than for Lonjsko Polje; however, the reasonfor this is perhaps that too few samples from theSava have been analysed. The fish of Lonjsko Poljeusually show a faster length-mass growth in their fryperiod, as compared with those from the Sava.Accordingly, it can be concluded that the water ofLonjsko Polje has greater trophicity and offers abetter food base for the growth and development offish, i.e., for ichthyoproduction.



6. KAKVOÆA STANIŠTA IINDIKATORSKE VRSTE

Indikatorske vrste riba koje za podruèje Lonjskogapolja mogu pokazati promjenu kakvoæe staništa su:karas ( ), èikov (

), linjak ( ) i crvenperka () te belica ( ) i

crnka ( ), kao dvije vrste kojima joštreba utvrditi prisutnost. Nestanak tih vrsta izpodruèja Lonjskoga polja znaèio bi potpunopromijenjene uvjete staništa. Poznavanje stanja istupnja poremeæenosti vodenog ekosustavapreduvjet je optimalnoga gospodarenja njima,njihove zaštite i obnove. U novije vrijeme, klasièneanalitièke metode i naèini odreðivanja i mjerenjapromjena koje se dogaðaju u vodenim ekosustavimasve se više dopunjuju pristupima u kojima seprimjenjuju bioindikatorske sposobnosti �ivihorganizama. Najveæi dio slatkih voda nastanjen jeribama koje mogu signalizirati ne samo trenutaènepromjene nego i one koje se dogaðaju unutar du�ihvremenskih razdoblja. Odnos èovjeka prema ribamaobièno je vrlo pozitivan, pa javnost naglašenoodgovara na štetu napravljenu na ribama (a time i navodi). Masovna smrtnost riba dramatièan je znak kojiupozorava da je vodena zajednica u kritiènom stanju ida se tamo dogaða nešto što bi moglo biti pogibeljnoza ribe. Sposobnost neke ribe za osjetljivoodgovaranje na promjene u slo�enom vodenomokolišu, na odstupanja od normalnih vrijednostinjegovih razlièitih èimbenika te za oznaèavanje èak ikratkotrajnih nepravilnosti ili za bilje�enjedugotrajnih, ali vrlo malih kolièina zagaðivala,predodreðuje takvu ribu za ulogu bioindikatora. Na tajnaèin ribe mogu zamijeniti analize i praæenje koje biinaèe moralo biti izvedeno pomoæu slo�ene i skupeaparature. Ribe imaju potrebne osobine za funkcijubioindikatora u okolišu u kojemu �ive. Tijekom �ivotaribe su vezane uz vodeni okoliš, koji ne mogu nipovremeno napustiti. Bioindikatorsko oèitovanje isignalizacija riba mogu biti istra�ivani i procjenjivanina razini zajednica, populacija ili na razini jedinka.Riblje zajednice (raznolikost vrsta, kvantitativnièimbenici) pokazuju kakvo je stanje vodenog okolišau cjelini. Sastav vrsta riblje zajednice prvotno jeodreðen kakvoæom vode, posebno temperaturom,re�imom kisika te takoðer hidrološkim i morfološkimsvojstvima vodenog okoliša. S druge strane, nastvaranje prirodne riblje zajednice u danim uvjetimautjeèu i biološke osobine te ekološki zahtjevipojedinih ribljih vrsta. Meðudjelovanja abiotièkih i

Carassius carassius Misgurnus

fossilis Tinca tinca Scardinius

erythropthalmus Leucaspius delineatus

Umbra krameri

6. HABITAT QUALITY ANDINDICATOR SPECIES

Indicator species of fish that can show changes inhabitat quality in Lonjsko Polje are: the Crucian carp( ), weather loach (

), tench ( ) and common rudd( ) as well as the sunbleak( ) and European mudminnow( ), in addition to two species thepresence of which is still to be established. Thedisappearance of these species from the LonjskoPolje area would mean total change of habitatconditions. Knowledge of the state and degree ofderangement of the aquatic ecosystem is aprecondition for optimum management of it, itsprotection and renewal. In recent times, classicalanalytical methods and manners of determining andmeasuring changes that are going on in waterecosystems are increasingly being supplementedwith approaches in which the bioindicator capacitiesof living organisms are employed. Most fresh water isinhabited by fish that can signalise not only currentchanges but also those that go on within a longerperiod of time. The human attitude to fish is usuallyvery positive, and the public makes a strongresponse to hard done to fish and hence to the water.Mass mortality of fish is dramatic sign, warning thatthe aquatic community is in a critical state and thatsomething is going on that could be fatal for the fish.The capacity of some fish to respond sensitively tochanges in the complex aquatic environment, todeviations from the normal values of its variousfactors and to indicate even short-term irregularitiesor the marking of long-term but very small quantitiesof pollutants predetermines such fish for the rule ofbioindicator. In this manner fish can replace analysisand monitoring that would otherwise have to becarried out with complex and expensive apparatus.Fish have the necessary traits for the function ofbioindicator in the environment in which they live.During their lifetimes fish are related to the aquaticenvironment, which they cannot leave even for ashort time. The bioindicator response and signals offish could be investigated and evaluated at the levelof community, population or individual. Fishcommunities (species diversity, quantitative factors)show what the state of the aquatic environment as awhole is. The species composition of the fishcommunity is primarily determined by water quality,the oxygen regime and by hydrological andmorphological characteristics of the aquaticenvironment. On the other hand, biological factorsand the ecological demands of given piscine speciesdo also affect the creation of the fish community in thegiven conditions. The interaction of biotic and abiotic

Carassius carassius Misgurnusfossilis Tinca tincaScardinius erythropthalmusLeucaspius delineatusUmbra krameri



37

biotièkih èimbenika odreðuju stvaran sastavihtiofaune u vodotoku, jezeru, bazenu ili akumulaciji.

U vrijeme kada je utjecaj ljudskih aktivnosti navodene ekosustave bio najmanji, sastav vrsta ribljihzajednica bio je u skladu s osobinama prirodnogvodenog okoliša. Sastav vrsta ribljih zajednica kojenastanjuju neku vodu rezultat je kompleksa biotièkih iabiotièkih èimbenika, ukljuèujuæi ribarsko gospoda-renje njima. Promjene u raznolikosti vrsta naglašensu znak koji upuæuje na to da se u vodenomekosustavu dogodila znatna i, obièno, posrednapromjena jednog ili više èimbenika. Promjene na kojeupuæuje nestajanje ili pojavljivanje odreðenih ribljihvrsta mogu biti posljedice promjena kakvoæe vode ilihidroloških i morfoloških obilje�ja vodotoka. Sobzirom na to da riblja zajednica djeluje kao slo�enbioindikator u kojemu se promjene nakupljaju,njegova signalizacija mora se odgonetnutipostupnom analizom ihtioloških, gospodarstvenih,hidroloških, kemijskih i drugih podataka kako bi seodredio uzrok ili uzroci promjena u ribljem fonduvodenoga staništa.

Nestanak ribljih vrsta osjetljivih na pogoršanjekakvoæe vode zbog organskoga oneèišæenja (iproizlazeæe mijenjanje re�ima kisika) najèešæa jepojava koja se uoèava ispod brojnih toèkastih izvorakanalizacijskog oneèišæenja. Bioindikatorski signali,premda u velikim vodotocima sporiji nego u malim,ipak su dovoljno jasni.

Ureðivanje velikih vodotoka dovodi do postupnoganestanka odreðenih vrsta i do promjenameðusobnog odnosa pojedinih vrsta. Broj ekološkiodreðenih, ali neprilagodljivih vrsta, koje suekonomski najva�nije, iscrpljen je i zamijenjen manjeodreðenim i prilagodljivijim vrstama. Takav se procesdogodio u veæini velikih europskih rijeka, kojih sukorita kanalizirana (Dunav, Rajna, Majna, Elba idruge).

Ribe se obièno povezuju s bioindikacijom negativnihprocesa ili negativnih pritisaka koji se pojavljuju uvodenom okolišu. Riblji fond se pokazao kao vrlopr ik ladan bio ind ikator rev i ta l izac i jsk ih irenaturalizacijskih prilagoðavanja tokova. Ribe seprimjenjuju i kao test organizmi u biološkimanalizama vode pri kritiènim oneèišæenjima.Promjene populacijskih èimbenika vrsta u vodenimstaništima takoðer imaju veliko bioindikatorskoznaèenje. Promjene na razini populacije umnogomesu posljedica djelovanja razlièitih utjecaja(odstupanja od normale). Promjene broja i biomaseunutar populacije prvotno su uzrokovanepogoršanjem vodenog okoliša, što djeluje na

factors determine the real composition of theichthyofauna in a stream, lake, pool or reservoir.

In the time when the impacts of human activities onthe aquatic ecosystems were the least, the speciescomposition of the fish communities was in harmonywith the features of the natural aquatic environment.The species composition of fish communities thatinhabit some stretch of water is the result of acomplex of biotic and abiotic factors, including themanagement of the fishery. Changes in speciesdiversity are a pronounced sign that indicates thatsome major and usually indirect change of one ofmore factor has happened in the aquatic ecosystem.Changes that indicate the disappearance ofappearance of given fish species can be theconsequences of changes in water quality or of thehydrological and morphological traits of the stream.Since the fish community acts as a complexbioindicator in which changes are cumulative, thissignal must be decoded by a gradual analysis of theichthyological, economic, hydrological, chemical andother factors so as to determine the cause or causesof changes in the fish stock of the aquatic habitat.

The disappearance of fish species sensitive todeterioration of water quality as a result of organicpollution (producing changes in the oxygen regime)is the most frequent phenomenon that can be seenbelow the numerous scattered sources of effluentpollution. Bioindicator signals, although slower inlarge streams than small ones, are neverthelessclear enough.

The straightening of the major streams leads to agradual disappearance of certain species and tochanges of the interrelations of the given species. Anumber of ecologically fixed and inadaptablespecies that are the economically most important areexhausted and replaced by less specific and moreadaptable species. This kind of process occurred inmost of the great European rivers the courses ofwhich have been impounded (Danube, Rhine, Mainand Elbe).

Fish are usually connected with the bioindication ofnegative processes of negative pressures that occurin the aquatic environment. Fish stocks have shownto be a very suitable bioindicator of revitalised and re-naturalised adjustments of streams. Fish are used astest organisms in biological analyses of water incritical pollution events. Changes of populationfactors of species in aquatic habitats also have majorbioindicator importance. Changes at the populationlevel are very much the consequence of the effect ofdiffering influences (deviations from the norm).Changes in number and biomass inside a populationare primarily caused by deterioration of the aquaticenvironment, and affect the chemical and physicalcharacteristics (eutrophication, primarily) as well as




kemijska i fizikalna obilje�ja (ponajprije eutrofikacija)te na hidrološka svojstva i morfologiju korita rijeke.Smanjenje brojnosti populacije prvotno je rezultatsmanjenoga uspjeha prirodne reprodukcije, kao ipoveæane smrtnosti odreðene starosne skupine upopulaciji. Sve dok se takve promjene na razinipopulacije ne uspore i ne zaustave (drugim rijeèima,sve dok jaèina uzroènoga èimbenika raste), postupnosmanjenje brojeva populacija mo�e, u krajnjemsluèaju, dovesti do nestajanja vrsta iz nekog staništa.Opisani proces prati smanjenje prosjeène starosti upopulaciji zbog poveæane smrtnosti i smanjenjamaksimalne dugovjeènosti. Takve manifestacije narazini populacije mogu se prouèavati zasebno,posebno u populacijama ribljih vrsta koje sadr�ejedinke srednje i visoke starosti.

Nepravilnosti u starosnoj strukturi ribljih populacija(npr. nedostatak predstavnika nekoga godišta)obièno su posljedica neuspjele reprodukcije ilikatastrofalnog uništenja mlaða. Ta je pojava osobitoopasna za odr�anje kratko�ivuæih vrsta. Npr., bujicenakon oluja, koje donose veliku kolièinususpendiranih èestica gline, tijekom inkubacijeobièno uništavaju sva jaja pojedinih vrsta. Posebnosu ugro�ene vrste koje se odjednom mrijeste uogranièenim podruèjima, kao npr. podust( ).

Na razini jedinke promjene u vodenom okolišupostaju oèite, ponajprije po razlièitim posljedicama nabiološke procese pojedinih riba. Npr., intenzitet rastase usporava kao odgovor na loše uvjete kisika inedostatak hrane zbog oslabljenih uvjeta zaorganizme koji èine hranu ili zbog natjecanja za hranuizmeðu autohtonih i unesenih vrsta. Isto tako, u vrlozagaðenim vodama mo�e se zapaziti oslabljenoukupno stanje pojedinih riba, ukljuèujuæi potvrðenemanifestaci je loši jeg zdravl ja. Smanjenareproduktivna sposobnost jedinka mo�e biti još jednaposljedica nepovoljnih uvjeta okoliša.

Naglo poveæanje upotrebe kemijskih sredstava ugotovo svim ljudskim djelatnostima dovelo je dobrojnih negativnih posljedica èije bi odreðivanje imjerenje u vodenom okolišu bilo te�e beziskorištavnja riba kao bioindikatora. Vrlo vrijednaosobina riba je sposobnost nakupljanja zagaðivala(kemijskih sastojaka) iz vode, što omoguæujeodreðivanje izrazito kratkotrajnoga zagaðenja (akoono ne ubije ribe) ili vrlo niskih razina dugotrajnihzagaðivala. Takva zagaðivala ukljuèuju teške metale,pesticide, PCB spojeve, radionuklide i druge tvari èijenakupljanje u ribljim organizmima omoguæuje njihovouspješno otkrivanje.

Chondrostoma nasus

the hydrological characteristics and the morphologyof the profile of the course of the river. Reduction ofthe abundance of a population is primarily the resultof the reduction in natural reproduction success andincreased mortality of certain age groups in thepopulation. Until such changes at the populationlevel are slowed or halted (in other words, as long asthe strength of the causal factor grows), the gradualreduction of the numbers of the populations may,ultimately, lead to the disappearance of species fromsome habitat. This process is accompanied by areduction of the mean age in the population becauseof increased mortality and reduction of maximumlongevity. Such manifestations at population levelcan be studied separately, especially in populationsof fish species that contain individuals of averageand great age.

Irregularities in the age structure of fish populations(for example, the shortage of representatives ofsome year class) are usually the consequence ofreproduction failure or some catastrophic decimationof the fry. This is a phenomenon that is particularlydangerous for the viability of short-lived species. Forexample, a torrent after a storm, bringing with it agreat quantity of clay particles will often destroy allthe eggs of some species during incubation. Speciesthat all spawn together in limited areas, such as thecommon nase ( ), areparticularly endangered.

At the level of individual, changes in the aquaticenvironment become manifest primarily according tothe various consequences to the biological processof the given fish; for example, vigour of growth slowsas response to poor oxygen conditions and shortageof food because of the weakening of the conditionsfor the organisms that constitute the food or becauseof the food competition among indigenous andintroduced species. Similar, in very polluted waters,an overall debilitated state of given individual fish canbe seen, including recognised manifestations of poorhealth. The reduction of the reproductive capacity ofindividuals can be one more consequence ofunfavourable environmental conditions.

A sudden increase in the use of chemicals in almostall human activities has led to many negativeconsequences, the determination and measurementof which in the aquatic environment would be muchmore difficult without the use of fish as bioindicators.A very valuable feature of fish is their ability toconcentrate pollutants (chemical components) fromthe water, which enables the determination of veryshort-term pollutants (if they do not kill the fish) orvery low levels of long-term pollutants. Suchpollutants include heavy metals, pesticides, PCBcompounds, radionuclides and other substances theaccumulation of which in the fish organisms enablethem successfully to be detected.

Chondrostoma nasus



39

7. PROBLEMATIKA I ŠTETE ODUNESENIH VRSTA

Jedna od najozbiljnijih posljedica antropogenogutjecaja na naše ribe, izuzmemo li fizièke i kemijskepromjene staništa, svakako je unos stranih vrsta uneko podruèje. Pojedine introdukcije znaèe veæuopasnost od, primjerice, zagaðenja, melioracije i sl.Naime, dok se ti utjecaji lako uklone uklanjanjemuzroka, novoprilagoðenu je vrstu, na�alost,nemoguæe uništiti. Bez obzira kako ih mi zvali( invazivne, nenativne, strane, egzotiène,introducirane ili unesene vrste), to su one vrste kojesu evoluirale drugdje i ne nalaze se na podruèju svojeprirodne rasprostranjenosti jer su sluèajno ilinamjerno prenesene u novo stanište. Baš suunošenja novih invazivnih vrsta, zajedno s drugimutjecajima, od kojih je najveæi uništavanje prirodnihstaništa, jedan od glavnih razloga izumiranja vrsta uposljednjih stotinjak godina. Ako se odr�i u novojsredini, novounesena vrsta mo�e znatno promijenitizajednicu riba, što èesto dovodi do nestajanjaosjetljivih domaæih vrsta. Degradacija staništa i sveveæe oneèišæenje omoguæile su novounesenimvrstama lakšu prilagodbu i moguænost da postanuinvazivne.

Invazivne vrste mogu na više naèina utjecati nadomaæe vrste: jeduæi ih, konkurirajuæi im za hranu istanište, razmno�avajuæi se s njima i smanjujuæigenetièku raznolikost, unoseæi nove bolesti inametnike. Alohtone vrste najèešæe su unesene uovaj sustav djelovanjem èovjeka, s ciljem kojinajèešæe nikad i nije bio postignut. Takve zahvateizvode uglavnom ribolovna društva ili èak pojedincina svoju ruku, bez prethodne konzultacije sekolozima ili ihtiolozima. Posljedice su jednostavnonesagledive te u vodenim biotopima dolazi do burnihpromjena u kompliciranim hranidbenim lancima, dopojave raznih oblika interakcija meðu pojedinimvrstama, pa èak i do potpune ekstinkcije nekih vrsta.Opæe je prihvaæen stav da se na današnjem stupnjuznanja ne mogu predvidjeti dugoroène posljedicekoje æe unos nove vrste prouzroèiti.

Na istra�ivanom podruèju Lonjskoga polja pet seintroduciranih (alohtonih) vrsta dobro aklimatiziralo.To su sunèanica ( ), patuljastisomiæ ( ), babuška (

), bezribica ( ) i pastrvskigrgeè ( ). One ne utjeèupovoljno na sastav ihtiopopulacija i arealrasprostranjenosti sve im se više širi. Postoje još

Lepomis gibbosus

Ameiurus nebulosus Carassius

gibelio Pseudorasbora parva


7. THE PROBLEM OF AND HARMFROM INTRODUCED SPECIES

One of the most serious consequences ofanthropogenic impacts on fish in this country, if weexcept the physical and chemical changes of habitat,is certainly the introduction of foreign species into agiven area. Some introductions constitute an evengreater danger than, for example, pollution,reclamation and so on. While these impacts areeasily obviated by the removal of the causes, thenon-adapted new species often cannot,unfortunately, be eradicated. Irrespective of whatthey are called (invasive, non-native, foreign,exotics, introduced species), these are neverthelessspecies that evolved elsewhere and here are not inthe area of their natural distribution, because theyhave been accidentally or fortuitously transferred toa new habitat. These introductions of new invasivespecies, together with other impacts, the greatest ofwhich is the destruction of the natural habitats, areone of the main reasons for the extinction of speciesin the last hundred or so years. If it can maintain itselfin the new habitat, the newly introduced species canconsiderably modify the fish community, often thusleading to the disappearance of vulnerable domesticspecies. The degradation of habitats and the ever-greater pollution have enabled newly-introducedspecies to be able to adapt more easily and tobecome invasive.

Invasive species can affect domestic species inseveral ways: preying on them, competing for foodand habitats, reproducing with them and reducingthe genetic diversity, bringing in new sicknesses andparasites. Allochthonous species are most oftenbrought into the system by the activities of people,their objective most often never being achieved.Such operations are carried out mainly by anglingclubs or even individuals on their own initiative,wi thout consul ta t ion wi th ecologis ts orichthyologists. The consequences are oftenenormous and the water biotopes experienceagitating changes in the complicated food chains,the appearance of various forms of interactionamong the species, even to the total extinction ofsome species. It is a generally accepted view that atthe level of knowledge of today, it is impossible topredict the long-term consequences that can bebrought about by the introduction of a new species.

In the area of Lonjsko Polje investigated, fiveintroduced or non-indigenous species have becomewell acclimatised. These are the pumpkinseed( ), brown bullhead (

), Prussian carp ( ), falseharlequin ( ) and the

Lepomis gibbosus Ameiurusnebulosus Carassius gibelio

Pseudorasbora parva




èetiri unesene vrste riba koje se pojavljuju u Savi iUni, a èija je prisutnost na podruèju PP Lonjsko poljetakoðer moguæa. Meðu tim èetirima vrstama su bijeli isivi glavaš, bijeli amur i kalifornijska pastrva.

Zakoni o slatkovodnom ribarstvu i zaštiti prirode našezemlje strogo zabranjuju unos novih vrsta udefinirane otvorene ekosustave. Štete koje su novevrste izazvale u ihtiofauni Lonjskoga polja vrlo jeteško kolièinski procijeniti jer se brojèani odnosipojedinih vrsta intenzivno prate tek nekolikodesetaka godina, ali je brojnost pojedinih alohtonihvrsta na odreðenim lokacijama zabrinjavajuæa.

Najbrojnija je i najprisutnija na svim istra�ivanimlokalitetima sunèanica, koja je u Hrvatsku unesenaveæ poèetkom 20. stoljeæa. Dok je u rijeci Savi manje-više sporadièno prisutna, u Lonjskom polju jenajbrojnija riba na veæini stajaæih staništa. Mrtvaje iiskopi èitavog podruèja prepuni su riba te vrste, što jevrlo zabrinjavajuæe.

Druga je po brojnosti, ali i po šteti koju èini, patuljasti iliamerièki somiæ. Na podruèju Hrvatske pojavljuje setakoðer od poèetka 20. stoljeæa. Vrlo guste populacijezabilje�ene su u veæini mrtvaja i iskopa.

Veliki je problem za autohtonu ihtiofaunu Hrvatske,pa i ovoga podruèja, babuška. Od gotovo nepoznatevrste u pedesetim godinama 20. st., ona je do danasprešla put do invazivne vrste zbog vrlo brojnihpopulacija, zabilje�enih u mnogim vodama. Prisutnaje u velikim kolièinama u svim vodama i crnomorskogi jadranskog slijeva. Babuška je izravni suparnikšaranu (divljim populacijama) èije su se populacijerazmjerno smanjile. Njezini utjecaji i posljedice naostalu ihtiofaunu nisu poznate.

Ribarski struènjaci sla�u se da je u Hrvatskoj unosbezribice ( ) izazvao promjene uzajednicama riba. Ta mala ribica unesena je oko1960. u Rumunjsku iz Kine (pokrajina Yang TseKiang). Toèan datum unosa u našu zemlju nijepoznat, ali se pretpostavlja da je 70-ih godina veæ bilaprisutna. Osamdesetih godina naðena je u svimribnjacima i u veæini vodotoka. Danas ta vrstanaseljava gotovo sve vode gdje je provoðenoporibljavanje šaranom. Promjene i prilagodbe ribljihzajednica tek slijede.

Rijekama Hrvatske u plovama pluta i bijeli amur.Brojnost te vrste u Dravi je navodno tako velika daozbiljno ugro�ava prirodne populacije ostalih vrsta,dok za Savu nema nikakvih podataka. Èak sepostavlja pitanje odakle tolike populacije te vrste kadje poznato da se ona ne mrijesti u otvorenim vodama.Unesen je u naše vode 60-ih godina radi akvakulture.

Pseudorazbora parva

largemouth bass ( ). They donot have a positive effect on the composition of theichthyopopulation and the area of their distribution isconstantly expanding. Four other introduced speciesappear in the Sava and Una, and their presence inthe area of Lonjsko Polje Nature Park is also verypossible. Among these four species are the big headcarp and silver carp, grass carp and rainbow trout.

The freshwater fishing and nature protection laws ofour country strictly ban the introduction of newspecies into defined open ecosystems. The damagethat the new species have caused in theichthyofauna of Lonjsko Polje is difficult to estimatein quantitative terms, because the numericalrelations of the individual species has beenvigorously monitored only for a few dozen years;nevertheless, the numbers of some allochthonousspecies in certain locations is perturbing.

The most numerous and most omnipresent speciesat all the research sites is the pumpkinseed, whichwas introduced into Croatia as early as the beginningof the 20th century. While in the Sava River it figuresmore or less sporadically, in Lonjsko Polje it is themost numerous fish in most of the standing habitats.The oxbows and pits in the whole area are full of thisspecious, which gives cause for deep concern.

The second in terms of numbers and in terms of thedamage it does is the brown bullhead. It has alsobeen found in Croatia since the beginning of the 20thcentury. Very dense populations have been recordedin most of the oxbows and excavations.

One great problem for the indigenous ichthyofaunaof Croatia and of the whole problem is the Prussiancarp. While it was an almost unknown species in the1950s, today it has become an invasive species,because of the very large populations recorded inmany waters. It is present in great quantities in allwaters of the Black Sea and Adriatic drainage areas.The Prussian carp is a direct competitor of the carp(wild populations) the populations of which havebeen reduced in proportion. Its impacts andconsequences on the remainder of the ichthyofaunaare not known.

Fishing experts concur that the introduction of thefalse harlequin ( ) has causedchanges in fish communities. This small fish wasintroduced into Romania about 1960 from China(Yang Tse Kiang province). The precise date itentered out country is not known, but it can beassumed that it was present as early as the 1970s. Inthe eighties it was found in all fishponds and in moststreams. Today this species has colonised almost allwaters were the introduction of carp has been carriedout. Changes and adjustments of the fishcommunities are still to come.


Pseudorazbora parva


41

U rijeci Savi se mogu naæi još dvije azijske vrste, bijelii sivi glavaš (tolstolobik). Obje su takoðer unesene60-ih godina 20. stoljeæa u svrhu uzgoja u ribnjacima,a koriste se i za smanjivanje kolièine fito i zooplanktona u stajaæim vodama. Njihova brojnost uSavi je relativno mala jer su tu dospjeli sluèajno,bijegom iz šaranskih ribnjaka.

The grass carp too swims in shoals in the rivers ofCroatia. The numbers of this species in the Drava areallegedly so great that it seriously jeopardises thenatural populations of the other species, while thereare no data for the Sava. Often asked is the questionwhence such large populations of this species, whenit is well known that it does not spawn in open waters.It was introduced into our waters in the 1960s for thesake of fish farming.

Two more Asiatic species, the big head carp andsilver carp (tolstolobik) can also be found in the Savariver. Both were also imported in the 1960s, for thesake of fish farming, and they are also used forreduction of the quantities of phyto- and zooplanktonin stagnant water. Their abundance in the Sava isquite small because they arrived only fortuitously,escaping from the carp fishponds.



8. STRUKTURA ZAJEDNICA RIBAOPISANA POMOÆU INDEKSARAZNOLIKOSTI

Raznolikost vrsta riba na pojedinom staništuodreðena je brojem razlièitih vrsta, brojnošæu istrukturom, a prikazana indeksom raznolikosti. Ribesu nepristupaène vizualnom promatranju, asakupljanje uzoraka da bi se dobila èak i površnaslika strukture zajednice zahtijeva dugotrajan napor.

Ribe slu�e kao hrana posebno pticama, a svojombrojnošæu i masom ukljuèene su u gotovo sveprehrambene lance viših kralje�njaka. Poznato je daribe svojom brojnošæu mogu ozbiljno promijenitibiocenoze u kojima se nalaze. Zato su od velikogaznaèenja spoznaje o kvantitativnim pokazateljimastanja ihtiocenoza, kroz ihtiomasu po hektaru, kao ikvantitativnim odnosima pojedinih vrsta. Koje vrste injihove biomase dolaze na podruèju PP Lonjsko poljetreba dati kroz osnovne numerièke parametrezajednice riba. Nju treba opisati uz pomoæ

8. THE STRUCTURE OF FISHCOMMUNITIES DESCRIBED WITHTHE USE OF THE INDEX OFDIVERSITY

The diversity of fish species in a given habitat isdetermined by the number of diverse species, theabundance and structure, and is shown by the indexof diversity. Fish are inaccessible to visual checks,and the collection of a sample to get even asuperficial image of the structure of a communitydemands a lasting effort.

Fish serve as food in particular to birds, and withtheir abundance and mass are involved in almost allthe food chains of the higher vertebrates. It is knownthat with their abundance fish can seriously changethe biocoenosis in which they are located. Soknowledge of the quantitative indicators of the stateof the ichthyocoenosis, through the ichthyomass perunit of area (per hectare) as well as quantitativerelations of individual species are of greatimportance. Which species come to the area ofLonjsko Polje Nature Park and what the biomass of



43

neparametrièkih modela (6 najèešæih indeksaraznolikosti) i modelom logaritamske serije.

Shannon-Wienerov indeks kao mjera raznolikostizajednice riba pokazuje nešto više vrijednosti zaSavu. Poveæana raznolikost zajednice riba u Savi uodnosu prema Lonjskom polju tumaèi se limnofilnimkarakterom zajednice Lonjskoga polja.

Simpsonov indeks, koji preferira èeste vrste, zapostaje Lonjskoga polja za koje imamo podatkeiznosi 0,89. Shannon-Wienerov na svim istra�enimpostajama zajedno iznosi 3,60, Brillouinov indekscijele kolekcije iznosi 3,55.

Strukturu zajednice treba opisati modelomlogaritamske serije (Williams, 1964.). Na taj naèinkvalitativna zajednica riba odreðena je sa dvaparametra: vrijednošæu alfa ibrojem prisutnih jedinka.

Teorijski pravac i ukupna serija prilièno se dobropodudaraju, premda se vidi lagana tendencija premalogo normalnom modelu. Naime, èitava krivulja, kojabi u logaritamskom obliku trebala biti pravac, imadonekle oblik s krivulje. Bogatstvo vrsta, R izra�eno uobliku R=s/log (N), iznosi 7,28.

Cilj je odrediti stvarnu raznolikost i strukturuzajednice teoretskim vrijednostima koje se moguprimijeniti i u drugim prostorima i u drugom vremenu.Te vrijednosti uz èitav niz ribarskih teoretskihparametara va�ne su za dobivanje teoretskihspoznaja o ihtiocenozama i stupnju njihovaiskorištenja.

Tablica 4. Indeks raznolikosti ihtiofaune za nekapodruèja Lonjskoga polja

(vrijednost = 3,88)

them is should be given through the basic numericalparameters of the fish community. This has to bedescribed with the use of non-parametrical models(the six most common diversity indices) and thelogarithmic series model.

The Shannon-Wiener index as diversity criterion fora fish community shows a somewhat higher value forthe Sava. This increased diversity of the fishcommunity in the Sava than in Lonjsko Polje can beinterpreted by the limnophilous character of theLonjsko Polje community.

The Simpson index, which prefers frequent species,comes for the Lonjsko Polje for which we have datato 0.89. The Shannon-Wiener amounts in all stationsinvestigated to 3.60. The Brouillon index of the wholecollection comes to 3.55.

The structure of the community should be describedby the logarithmic series model (Williams, 1964). Inthis way the qualitative fish community is determinedby two parameters: the alpha value and the numberof individuals present. ( vrijednost = 3,88)

The theoretical plot and the whole series correlatefairly well, although a slight tendency can be seentowards log normal model. That is, the entire curvethat in logarithmic form should be the plot has tosome extent the shape from the curve. The speciesrichness, R, expressed in the form of R=s/log (N),comes to 7,28

The objective is to determine the real diversity andthe structure of the community with theoreticalvalues that can be applied in other spaces and inanother time. These values in conjunction with anentire sequence of theoretical fish parameters areimportant to obtain theoretical understanding of theichthyocoenoses and the degree to which they areused.

Table 4. Index of diversity of ichthyofauna forsome regions of Lonjsko Polje




9. PROBLEMI POVEZANI SASMANJENJEM RIBLJIHPOPULACIJA

Posljednjih desetljeæa u cijelom je toku Dunavazabilje�en drastièan pad ulova riba (Holèik, 1998.;Mero i sur., 1998.; Vasilescu, 1998.), ponegdje èak ina samo èetvrtinu prethodnoga, kao posljedica višeantropogenih èimbenika. Posebno va�ni èimbenicinestanka riba su melioracije rijeènoga korita,pregradnje rijeka branama, zatim eutrofizacija vode iunos teških metala, kao i mjestimièno vrlo izra�enkrivolov i prelov riba. U posljednjih 20 godina uoèen jevišegodišnji drastièni pad razine vode, povezan susporenim tokom rijeke i smanjenjem poplavnihzona. Posljedica je smanjenje podruèja za mrijest iprehranu riba. Istovremeno, unošene su alohtoneriblje vrste i vršen prelov postojeæih ihtiopopulacija.Uz to, pregrade na Dunavu, a poglavito Ðerdap,dovele su gotovo do istrjebljenja riba iz porodicejesetrovki (Acipenseridae).

Na zajednice riba utjeèu mnogi hidrološki igeomorfološki èimbenici, oneèišæenja itd., a njihovikumulativni zajednièki uèinci, èesto meðuovisni inaoko pojedinaèno mali, imaju jak utjecaj napopulacije riba. Grubo mo�emo reæi da najveæiutjecaj na promatrane populacije i tip zajednice ribaimaju abiotièki èimbenici, poput brzine i kakvoæevode, i s tim u vezi poveæanje eutrofije, a osobitovelièina poplavne zone.

Danas su rijeke Dunav i Sava, pa tako i Lonjsko polje,sve optereæenije otpadnim vodama. Optereæenja suzasad uglavnom organskoga porijekla i u letalnimdozama nema otrova biocidnoga karaktera. Dapaèe,najvjerojatnije zbog organskih otpadnih voda dolazi dojaèe eutrofizacije, a s time do poveæanja ribljeprodukcije. Sve aktivnosti u parku prirode Lonjsko poljekoje dovode do oneèišæenja vode mogu nepovoljnoutjecati na ribe i ribarstvo. Kakvoæa vode - prvenstvenoglavnih opskrbljivaèa parka vodom - je bitna.

9.1. Nestanak i promjena prirodnihuvjeta staništa

9.2. Oneèišæenje

9. PROBLEMS RELATED WITHTHE REDUCTION OF FISHPOPULATIONS

In the last few decades, over the whole course of theDanube, a drastic fall in the catch of fish has beenregistered (Holèik, 1998.; Mero et al., 1998.;Vasilescu, 1998.), the consequence of severalanthropogenic factors. Factors that are particularlyimportant in the disappearance of fish are meliorationof the course of the river, impounding the river withdams, the eutrophication of the water and the input ofheavy metals, as well as poaching and over-fishing,which are very pronounced in places. In the last 20years, a long-term drastic fall in the water level hasbeen noted, connected with the decelerated course ofthe river and the reduction of the flood zones. Theconsequence of this is a reduction of the areas for fishspawning and feeding. At the same time,allochthonous species of fish have been introduced,and existing ichthyopopulations have been over-fished. In addition, the dams on the Danube,particularly Ðerdap, have led practically to theextirpation of fish from the sturgeon family(Acipenseridae).

Many hydrological and geomorphologic factors andpollution and so on affect fish communities, and theircumulative common effects, often interdependentand seemingly small individually, have a powerfulimpact on fish populations. Roughly we can say thatthe greatest impact on the observed populations andtype of fish community is exerted by abiotic factors,such as speed and quality of water, and in connectionwith this increased eutrophication, and in particular,the size of the flood area.

Today the Sava and Danube rivers, and so LonjskoPolje too are loaded with effluent. These loads are forthe moment mainly of organic origin and even in lethaldoses do not have any poison of a biocidal character.On the contrary, very likely because of the organiceffluent, there is stronger eutrophication, and henceincreased fish production. All activities in LonjskoPolje Nature Park that lead to water pollution mayhowever in excess have an unfavourable impact onfish and fishing. Water quality mainly of the mainwater supplies of the park is essential.

9.1. Disappearance and change of naturalhabitat conditions

9.2. Pollution



45

Do oneèišæenja opskrbljivaèa parka vodom mo�edoæi zbog:

upuštanja nedovoljno proèišæenih komunalnih iindustrijskih otpadnih voda,

spiranja s okolnoga terena, osobito spoljoprivrednih površina na kojima se provodiintenzivna poljoprivredna proizvodnja.

Od tih aktivnosti najva�niji su:

ispuštanje neproèišæenih otpadnih voda iz farma uvodotoke,

spiranje s poljoprivrednih površina na kojima seprovodi intenzivna biljna proizvodnja koju pratiprimjena agrokemikalija, u prvom redu umjetnihgnojiva i zaštitnih sredstava.

Na smanjenje poplavnoga podruèja i du�inu trajanjaplavljenja, odnosno na prostornu i vremenskudinamiku vodostaja na podruèju parka prirodeLonjsko polje, kao što je veæ naglašeno, veliki utjecajimaju promjene uvjeta veoma slo�enoga mehanizmapunjenja i pra�njenja Lonjskoga polja. Promjenauvjeta mehanizma punjenja i pra�njenja Lonjskogapolja posljedica je poglavito:

smanjenja visine vodostaja Save,

smanjenja visine vodostaja poplavnoga podruèjaSave,

regulacije vodotoka izvan podruèja parka prirodeLonjsko polje,

melioracije poljoprivrednih površina izvanpodruèja parka prirode Lonjsko polje.

Turizam i ribarstvo u okviru tradicionalnih aktivnosti neugro�avaju ihtiocenoze Lonjskoga polja. Suvremenomkoncepcijom razvoja, koji istovremeno podrazumijevazaštitu prirode i iskorištavanje resursa, došlo bi doturistièkog aktiviranja zaštiæenoga podruèja, aplanirane aktivnosti imale bi i šire gospodarske uèinkeza èitavo podruèje parka prirode, pa i za podruèje cijelePosavine. Pri posjeæivanju treba te�iti organiziranom iskupnom posjetu, pod vodstvom pouèenih vodièa,svjesnih vrijednosti podruèja. Posjetilaèke aktivnosti iprograme treba razvijati u za to predviðenim dijelovima

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9.3. Melioracije

9.4. Turizam

Pollution of the water supplies of the park can arisebecause of

discharge or release of insufficiently treatedmunicipal and industrial wastewater

run-off from the surrounding land, particularly fromagricultural land on which intensive faming iscarried out

Of these activities the most important are:

discharge of untreated farm effluent into thestreams

run-off from farmland on which intensive arablefarming is carried out, accompanied byapplications of agricultural chemicals, primarilyartificial fertilisers and protective preparations.

A major part in the reduction of the flood zone and theduration of inundations, that is the spatial andtemporal dynamics of the water-level in the area ofLonjsko Polje Nature Park, as already stated, isplayed by changes of conditions of the very complexmechanisms of the filling and emptying charging anddischarging of Lonjsko Polje. A change in theconditions of the mechanisms of the filling andemptying of Lonjsko Polje is the consequenceprimarily of:

reduction of the water level of the Sava

reduction of the water level of the Sava floodplain

regulation of the streams outside the area ofLonjsko Polje Nature Park,

reclamation of agricultural areas outside the areaof Lonjsko Polje Nature Park

Tourism and fishing within the framework of thetraditional activities do not jeopardise theichthyocoenoses of Lonjsko Polje. In thecontemporary concept of development, whichsimultaneously assumes nature conservation and theexploitation of resources, the protected area would beput to use in the tourist industry, and the plannedactivities would have broader economic effects for thewhole are of the nature park, and for the area of thewhole of Posavina. In visiting, organised and groupvisits should be preferred, guided by trained guides,aware of the values of the area. Visiting activities andprogrammes should be developed in parts of the parkset aside for this, and in this manner all the values of

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9.3. River engineering

9.4. Tourism




parka i na taj naèin prikazati sve vrijednosti parka, aistovremeno ostaviti biološke vrijednosti neošteæene.U tom smislu potrebno je napraviti studije kapaciteta ismještaja posjetitelja za vrijeme boravka u tompodruèju, moguænost njihova zadr�avanja i bavljenjaodreðenim tradicionalnim aktivnostima.

Moguænosti ribarskog turizma su mnogobrojne, a trebaih usmjeriti domaæoj obnovi kuæa i malim seoskimgazdinstvima, tradicionalnom ribolovu, muzejskimaktivnostima, itd. Turizam nosi i svoje opasnosti.

Izravni pritisci turizma na okoliš mogu se sa�eti ovako:

iscrpljivanje prirodnih resursa, što razumijevazauzimanje najvrjednijega prostora kopna i vode,destrukcije zbog po�ara i sl.;

vizualnu degradaciju prostora proizašlu izneprimjerena i neprihvatljiva naèina graðenja;

oneèišæenje vodotoka otpadnim vodama;

neodgovarajuæe zbrinjavanje komunalnog i drugogotpada;

poveæano oneèišæenje zraka i buka zbogpoveæanoga prometa; veæina gostiju dolaziprivatnim automobilima;

ošteæenje prirodne i kulturne baštine zbogprekobrojnih turista te zbog skupljanja endemiènihvrsta biljaka i �ivotinja;

stvaranje monokulture i napuštanje tradicionalnihdjelatnosti (poljoprivreda, ribarstvo) praæeno skoncentracijom stanovanja i aktivnosti u intenzivnimturistièkim podruèjima;

ugro�avanje lokalnoga naèina �ivota i socio-kulturnog identiteta;

nekontrolirana (i èesto nezakonita) gradnjavikendica koje zauzimaju podruèja namijenjenadrugim aktivnostima.

Ovdje valja naglasiti znaèenje ihtiofaune u prehraniptica. Ptice takoðer na neki naèin ugro�avaju ihtiofondLonjskoga polja. Od više od 150 vrsta ptica, 40-akvrsta se iskljuèivo ili povremeno hrani ribom, iz èegaproizlazi da se 30-ak % ornitofaune stalno koristi ribomkao hranom. U èitavoj Europi sve brojnije populacijecrnog vranca èine velike štete na ihtiopopulacijamaodreðenih podruèja i sve su veæi povici i zahtjevi da seta vrsta skine s popisa zaštiæenih i da se dopustiselektivni odstrjel.

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9.5. Ostali razlozi

the park can be shown, at the same time leaving itsbiological values undamaged. From this point of viewit is necessary to make studies concerning visitorcapacities and accommodation facilities during staysin the region, the ability for them to stay longer and totake part in certain traditional activities.

There are manifold opportunities for fishing tourism,and they should be headed towards the domesticrenovation of houses and to small rural holdings,traditional fishing, museum activities and the like.Tourism has its own dangers as well.

The direct pressures of tourism on the environmentcan be summed up as follows:

exhaustion of natural resources, which meansoccupation of the most valuable land and waterspaces, destruction because of fires and so on;

visual degradation of the space because ofinappropriate and unacceptable development;

pollution of streams with effluent'

inappropriate municipal and other wastewatermanagement;

increased air pollution and noise because ofincreased traffic; most visitors arrive in privatecars;

damage of natural and cultural heritage becauseof supernumerary tourists and because of thecollection of endemic species of flora and fauna;

creation of monoculture and abandonment oftraditional activities (agriculture, fishery)accompanied by concentration of housing andactivities in the vigorous tourist areas;

jeopardising the local manner of life and the socio-cultural identity;

uncontrolled and often illegal building of second-homes that occupy areas meant for otheractivities.

Here one should certainly stress the importance ofichthyofauna in the food of birds. Birds too in a senseendanger the fish stocks of Lonjsko Polje. Of themore than 150 bird species, 40 or so feed exclusivelyor occasionally on fish, from which it derives that asmuch as 30% of all avifauna feed constantly on fish.In the whole of Europe the increasingly numerouspopulations of cormorant do great damage to the fishpopulations of certain areas and there are increasingdemands to have the bird taken off the list ofprotected birds and to allow a cull.

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9.5. Other reasons



47

10. DOSADAŠNJI NAÈINKORIŠTENJA RIBARSTVA

Ribolov je u Savi, kao i u samom Lonjskom poljuoduvijek imao znatno i višestruko znaèenje. Svepopulacije nastanjene na obalama ovoga prostorahranile su se ribom, koja je bila va�na sastavnicanjihove prehrane, posebno tra�ena za vjerskihblagdana. Stoljeæima su ribolov i prerada ribe bileosnovne gospodarske aktivnosti lokalnogastanovništva u ovom podruèju. Tijekom posljednjih50 godina smanjivana su ribolovna pravatradicionalnim ribarima, sve do postupnog izumiranjanjihova zanata. Vrijednost ribe kao namirnice stalnose mijenja i ne mo�emo biti sigurni da ona u nekojbuduænosti opet neæe imati veliku vrijednost,meðutim ribarenje lokalnog stanovništva vjerojatnoviše neæe imati onu ekonomsku funkciju kakvu jeimalo tijekom 19. i 20. stoljeæa.

Lonjsko polje je najva�nije mrijestilište riba u ovomdijelu Hrvatske. U prošlosti je procijenjeno daprosjeèni godišnji ulov po hektaru površinepoplavnog podruèja iznosi 92 kg. Iako dosad nije biloopse�nijih istra�ivanja, pod pretpostavkom da nijedošlo do pada ukupne ihtioprodukcije, vjerujemo dase na tekuæim i poplavnim površinama ribolovnihpodruèja mo�e prosjeèno uloviti oko 500.000 kg ribe.

Najveæi utjecaj na ribe i ribarstvo PP Lonjskog poljaimaju hidrološke i hidrogeološke promjene,ponajprije kao posljedica promjena punjenja ipra�njenja Lonjskog polja izazvanih promjenamavode rijeke Save. Njihovi kumulativni zajednièkiuèinci, èesto meðuovisni i pojedinaèno naoko mali,imaju jak utjecaj na populacije riba.

Od dosadašnjih aktivnosti na prostoru parkanepovoljno djelovanje na raznolikost zajednice ribamogle su imati intenzivna poljoprivredna proizvodnja,odnosno spiranje agrokemikalija s poljoprivrednihpovršina i aktivnosti usmjerene na isušivanje vodenihstaništa, kao što su isušivanje i prenamjena prostora,regulacija vodotoka, melioracije poljoprivrednihpovršina.

10.1. Utjecaji na riblji fond

10.1.1.Antropogeno djelovanje

10. FISHING AS PRACTICED TODATE

Fishing in the Sava River, and in Lonjsko Polje itself,has always had a considerable and multifacetedimportance. All the populations inhabiting the banksof the area fed on fish, which was an importantcomponent of their food, and was particularly muchin demand on holydays. For centuries fishing and theprocessing of fish was the basic economic activity ofthe local population in the area. During the last 50years the rights of the traditional fishermen werecurtailed, until their craft gradually died out. Thevalue of fish as foodstuff constantly changes, and wecannot be sure that in some future it will not have agreater value; however, the fishing of the localpopulation probably will not have the sameeconomic function it had during the 19th and 20thcenturies.

Lonjsko Polje is the most important spawning groundfor fish in this part of Croatia. In the past it wasestimated that the annual average catch per ha of thefloodplain came to 92 kg.Although there has been nomore capacious research, on the assumption thatthere is not fall in total ichthyoproduction, we believethat in the running water and flooded areas of thefishing areas some 500,000 kg of fish could becaught today.

The major impacts on fish and fishing in LonjskoPolje Nature Park are made by hydrological andhydro-geological changes, mainly as a result of thechanges in the flooding and draining of Lonjsko Poljebrought about by changes in the water of the SavaRiver. The cumulative joint impacts of them, ofteninterdependent, and at first sight small, have apowerful influence on the fish populations.

Of the activities in the park to date, a negative impacton fish community diversity might have been playedby intensive farming, that is, the run off of agriculturalchemicals from the land, and activities aimed atdraining the aquatic habitats, as well as the drainingand changing land use, straightening of thewatercourses, reclamation of agricultural land.

10.1. Impacts on the fish stocks

10.1.1. Human activities




10.1.2. Športsko-rekreativni ribolov

Neprijeporno je park prirode Lonjsko polje ribarskivrlo zanimljiv kraj, kako za lokalno stanovništvo, takoi za veliki broj športskih ribièa, koji bi upravo u njemu�eljeli loviti ribu. Tom kraju gravitira velik brojšportsko-rekreativnih ribolovaca Siska, Zagreba,Novske, Kutine i drugih okolnih mjesta.Iskorištavanje bioloških resursa, a posebno ribe, usamom parku mora se provoditi vrlo oprezno i podstalnim nadzorom znanstvenika. Naime, ribe su, kaoosnova u svim prehrambenim lancima, va�ne zabrojèano stanje svih ostalih skupina kralje�njaka.Smanjenje prehrambene osnove imat æe zaposljedicu smanjenje i svih ostalih skupina uprehrambenom lancu.

Moguæi negativni utjecaji ribolova na vrijednosti parkaprirode mogu nastati samo zbog nepridr�avanjazadanih ogranièenja i mjera zaštite. Osobitonepovoljne posljedice mogu nastati zbog pregraðiva-nja ribljih putova i kanala tijekom mrijesta, nekontrolira-na izlova matica, te nekontrolirana selektivnog izlovapojedinih komercijalno vrijednih vrsta. Meðutim, uzpomoæ nadzorne slu�be i redovite kontrole naèinaobavljanja ribolova te nepovoljne posljedice se moguizbjeæi. Veliko je pitanje koliko sadašnja razinaiskorištavanja ihtiocenoza parka prirode Lonjsko poljeima utjecaja na biološku raznolikost cijeloga parka.

S obzirom na to da vode u posebno zaštiæenimdijelovima prirode nisu ribolovne vode u smislunovoga Zakona o slatkovodnom ribarstvu, odredbeZakona o slatkovodnom ribarstvu ne odnose se navode unutar granica parka prirode Lonjsko polje, alise odnose na riblji fond matiènog vodotoka Save.Stoga Park prirode Lonjsko polje mora Pravilnikom ounutarnjem redu odredit i poseban re�imiskorištavanja ihtiofaune Lonjskoga polja glederibolova i zaštite ribljeg fonda jer je opæe poznato dastanovništvo ovog podruèja tradicionalno obavljaribolov, i to ne samo alatima športsko-rekreacijskogribolova, nego i razlièitim vrstama mre�a i vrša, daklealatima gospodarskoga ribolova. Takoðer se ribaizlovljava i ilegalno prijestorima, upravo prilikomprolaska kroz ustavu Trebe� (kao i na Strugu i drugimlokacijama) kada ribe u velikom broju ulaze u Lonjskopolje na mrijest.

Studija treba dati osnovne odgovore na pitanja je limoguæe i koliko ribe loviti u podruèju parka. Posebnoje osjetljiva lokalna zajednica koja u smanjenjuribolovnih prava vidi ugro�avanje vlastiteegzistencije. Ribarstvo treba uklopiti u tradicionalniodr�ivi razvoj naselja u zaštiæenom podruèju. Dosadza športsko-rekreativni ribolov uglavnom nije bilo

10.1.2. Sporting and recreational fishing

It is incontrovertible that Lonjsko Polje Nature Park isa very interesting area for angling, both for the localpopulation and for a large number of anglers whowould like to fish in it. A large number of sporting andrecreational anglers from the areas of Sisak, Zagreb,Novska, Kutina and other places gravitate towardsthe area. And yet exploitation of the biologicalresources of the park, particularly of the fish, has tobe carried out very carefully and under constantscientific supervision. For the fish, the base of thefood changes, are very important for the abundanceof all the other groups of vertebrates. Any attrition ofthe food base will result in the reduction of all theother groups in the chain.

Possible negative impacts of fishing on the values ofthe nature park can occur only if the set restrictionsand protection measures are ignored. Particularlyharmful consequences can occur if the fish pathsand channels during spawning are impounded, byuncontrolled fishing of the mainstream anduncontrolled selective fishing of individualcommercially valuable species. However, with thehelp of a monitoring service and regular control of theway fishing is carried out, these detrimental effectscan be forestalled. A great matter is how much thecurrent level of the use of the ichthyocoenoses ofLonjsko Polje Nature Park has had an impact on thebiological diversity of the whole park.

Because the waters in the particularly protectedparts of nature are not fishing waters in the sense ofthe new Freshwater Fishing Law, the provisions ofthis law do not refer to water inside the borders ofLonjsko Polje Nature Park, but do refer to the fishstock in the main stream of the Sava River. ThusLonjsko Polje Nature Park must have its own HouseRules determining a special regime for theexploitation of the ichthyofauna of Lonjsko Poljeconcerning fishing and the protection of the fishstocks, because it is generally known that thepopulation of this area carries out fishing not onlywith the implements of the angler, but also withvarious kinds of net and pot, with the implements,that is, of commercial fisheries. The stocks are alsofished out illegally with barriers just as they passthrough the Trebe� sluice (as at Strug and otherlocations) when the fish enter Lonjsko Polje in largenumbers for spawning.

A study should provide the basic answers to thequestion of whether it is possible to fish in the park atall, and if so in what quantities. A particularlysensitive issue is that of the local community, whichsees a threat to its own ability to earn a living in thereduction of fishing rights. Fishing should be fittedinto the traditional sustainable development of thesettlements in the protected area. So far there have



49

ogranièenja ni zabrana. Radi zaštiæenosti podruèjašportsko-rekreacijski ribolov treba prakticirati naotvorenim vodama Save i na pojedinim, unaprijedodreðenim, mjestima unutar polja.

Postoje i mišljenja da športsko-rekreacijskomribolovu unutar parka prirode nema mjesta, kako stojii u zakonskim propisima prema Zakonu oslatkovodnom ribarstvu. Isto tako, èlanak 5. Zakona oslatkovodnom ribarstvu predviða proglašavanje izaštitu prirodnih mrijestilišta ako je mriješæenje riba utim vodama od osobite gospodarske va�nosti.Lonjsko polje ima sve elemente jednog od najva�njihi najveæih mrijestilišta porjeèja Save, pa bi ga prematome trebalo proglasit i va�nim prirodnimmrijestilištem, va�nim za oèuvanje ihtiopopulacijaèitavoga podunavskog slijeva.

Iz svega toga mo�emo zakljuèiti da športsko-rekreacijski ribolov, uz pridr�avanje svih ogranièenja imjera zaštite, ne bi trebao imati prevelik utjecaj nastanje ribljih populacija. Veliki je problem, meðutim,znanstvena provjera takvih iskustvenih podataka.

Veæina vrsta riba za sada nije ugro�ena. Najveæi suproblemi promjene zajednica pod utjecajem alohtonevrste babuške i kakvoæa vode. U posljednjih 50godina neke vrste su smanjile svoju brojnost, neke sunestale, ali ukupne ihtiomase ribe Lonjskog polja sujednake. To podruèje još je najveæe i najznaèajnijemrijestilište riba Dunava i Drave. Oèuvana prirodnasredina omoguæava �ivot velikom broju vrsta, pa ionima koje su u drugim dijelovima Europe veæišèezle.

10.1.3. Ugro�enost ribljih vrsta

been no restrictions on sporting and recreationalfishing. For the sake of protecting the area, this kindof fishing should be practised only on the openwaters of the Sava and at certain set places insidethe common.

Some people are of the opinion that there is no roomfor sporting and recreational fishing inside a naturepark, as stated by the regulations of the FreshwaterFishing Law. Article 5 of this Law provides for theproclamation and protection of natural spawninggrounds if the spawning of the fish in these waters isof particular economic importance. Lonjsko Poljehas all the elements of one of the most important andlargest spawning grounds of the Sava basin, andaccordingly should be pronounced an importantnatural spawning ground that is important for thepreservation of the fish population of the Danubebasin.

From all this we can conclude that sporting andrecreational fishing, assuming the adherence to allconstraints and protection measures, should nothave too great an impact on the state of the fishpopulations. A large problem does, however, inherein obtaining scientific confirmation of suchexperience-derived data.

For the moment, most fish species are notendangered. The greatest problems are the changesof the communities brought about by theallochthonous species the Prussian carp and bywater quality. In the last 50 years some species havehad their abundance reduced, some have vanished,but the total ichthyomass of the fish of Lonjsko Poljehas remained the same. This area is still the greatestand most important spawning ground of fish of theDanube and Drava rivers. The preserved naturalenvironment makes possible the life of manyspecies, even those that have already vanished inother parts of Europe.

10.1.3. Endangerment of fish species




11. PRIJEDLOG ZAŠTITNIHMJERA

11.1. Zaštita mrijestilišta i ostalihotvorenih voda

Jedna od najva�nijih mjera za poveæanje ukupneihtioprodukcije je oèuvanje prirodnih mrijesnihpodruèja i staništa gdje se ribe razmno�avaju.Posebno su zanimljivi stari plitki rukavci i pliæa mjestabogata biljem, kao i raznolikost staništa za pojedinevrste. Takva podruèja treba popisati i o njima voditibrigu. Neke od tih voda bilo bi nu�no regulirati tako dase ne mogu isušiti. Nekad je za pojedine reofilne vrstepotrebno umjetnim mrijestilištima nadomjestitinestala prirodna mrijestilišta. To je u posljednjevrijeme u svijetu vrlo popularna metoda.

Èimbenici koji pogoršavaju uvjete razmno�avanja naprirodnim mrijestilištima su:

regulacija voda kojom se isušuju vodena podruèjas idealnim uvjetima za mriješæenje pojedinih vrstariba

promjena razine voda na mrijesnim podruèjima zavrijeme mrijesta, inkubacije i ranog razvojalièinaka

oneèišæivanje voda (deterd�entima, insekticidimaili pesticidima i drugim kemijskim sredstvima)

preintenzivno nasaðivanje biljojednih vrsta ribakoje mogu opustošiti biljem obrasla podruèjaprirodnih mrijestilišta šaranskih vrsta

aktivnost ljudi koji u doba mrijesta na podruèjumrijestilišta svjesno ili nesvjesno ometaju ribe

krivolov riba za vrijeme mrijesta

radi oèuvanja mjesta na kojima se mrijestepojedine vrste riba potrebno je osigurati stalnurazinu vode za šaranske vrste u razdobljurazmno�avanja. Uspjeh mrijesta, izmeðu ostalog,ovisit æe i o ukupnoj kolièini vode u dobamriješæenja.

Ribarstvo na otvorenim vodama, osim nesumnjivaekonomskog uèinka, ima i èitav niz dodatnihsocioekoloških utjecaja, koji su mo�da i preèi.Ribolov i uzgoj ribe jedna je od najva�nijih djelatnosti

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11. PROPOSAL OFCONSERVATION MEASURES

11.1. Protection of spawning groundsand other open waters

One of the most important measures for increasingthe total ichthyoproduction is the preservation of thenatural spawning grounds and the habitats where thefish reproduce. Particular interest is attached to theold shallow branches and the shallow places that arerich in vegetation, as well as the diversity of thehabitats for the individual species. Such areas shouldbe scheduled and attention should be paid to them.Some of the waters should be regulated in such away as to prevent them drying out. Sometimes forindividual rheophilous species it will be necessary tocompensate for vanished natural spawning groundswith artificial spawning areas. This has become avery popular method globally of late.

Factors that have a detrimental effect on reproductionconditions in the natural spawning areas are:

regulation of water that dries up the watery areaswith ideal conditions for the spawning of variousspecies of fish,

changes in the level of the water in the spawninggrounds during the time of spawning, incubationand early development of the larvae

pollution of the water (detergents, insecticidesand pesticides, other chemicals)

over-intensive planting of herbivorous fishspecies that can lay waste plant covered areasthat are the natural spawning grounds of carpspecies,

human activities in spawning time in the area ofthe spawning grounds that deliberately orunwittingly disturb the fish,

poaching during spawning,

for the sake of the preservation of the sites at whichindividual fish species spawn, it is necessary tomaintain a constant level of water for carp speciesduring the reproduction period. Spawningsuccess, among other things, depends on the totalquantity of water during the spawning season.

Open water fishing, apart from its undoubtedeconomic effect, has a whole series of additional

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neposrednog iskorištavanja prirodnih bogatstavarijeka i naplavnih nizina. U okviru višenamjenskogiskorištavanja vodoprivrednog objekta ribarskogospodarenje ne dolazi u sukob s ostalimkorisnicima, pod uvjetom da se pri razvoju pojedinihdjelatnosti poštuju osnovna ekološka naèela. Teribolovno-gospodarstvene mjere vodotocima date suna temelju niza fizikalno-kemijskih, bioloških iekoloških parametara, skupljenih od razlièitihpojedinaca i institucija.

Predla�e se u poribljavanje otvorenih voda ukljuèitimrijestilišta za ekonomski zanimljive vrste, na razinièitave regije. (Takva mrijestilišta postoje u Jelas polju,Jasinju, Poljani ili treba izgraditi priruèno mrijestilišteuz vodotok Save.) Ministarstvo poljoprivrede išumarstva te pojedina športsko-ribolovna društvaimaju trajnu potrebu za veæim kolièinama divljih vrstariba (koje se gotovo i ne mogu kupiti na tr�ištu) pa, sobzirom na izvanredne moguænosti ovog podruèja,preporuèujemo vodoprivredi da u sklopu ekološko-edukacijskih programa potpomogne uvoðenjutehnologije mrijesta divljih riba, kao i ekonomskizanimljivih vrsta, naroèito smuða i šarana.Izmriještene lièinke raznih vrsta treba nasaðivati urukavce i zajezerene prostore uz glavni vodotok, seventualnom moguænošæu ispuštanja mlaða uotvorene vodotoke.

U razlièitim vodenim staništima te�i se stvaranju ribljepopulacije koja æe u najveæem stupnju iskoristiti sveprehrambene niše, a pojedine vrste i godištareducirat æe se športskim ribolovom.

Praktièno je nemoguæe izraditi toèan plannasaðivanja s vrstama, kolièinama i velièinama riba uoptimalnom razdoblju, a koji bi vrijedio dulje vremena.Najèešæe se dogaða da na tr�ištu nemaodgovarajuæih vrsta u potrebnoj velièini ili kolièini. Unaèelu, na tr�ištu slatkovodne ribe mogu se kupitisamo ekonomski va�nije ribe (šaran, amur, srebrni isivi glavaš, som i linjak).

Neka mrijestilišta bave se i mrijestom štuke. Mrijestsmuða u praksi se provodi uglavnom pomoæunaseljavanja smuðevskih gnijezda iz otvorenih voda.

Zatvaranjem ustave onemoguæava se prolazak ribana mrijest, kao i dotok hranjivih tvari, što u krajnjemsluèaju utjeèe i na cijeli hranidbeni lanac. Premanovom Prijedlogu Zakona o slatkovodnom ribarstvu,najstro�e je zabranjeno na bilo koji naèin sprjeèavatimigratorna kretanja riba na poplavljena podruèja injihov povratak u matièni vodotok. Èitav niz mjeraiznesen je u prilogu uvjeta za izgradnju ustave Trebe�II. U vodnogospodarskoj dokumentaciji treba odrediti

socio-ecological impacts that are perhaps evenmore important. Fishing and the cultivation of fish areamong the most important activities of the immediateexploitation of the natural riches of rivers andfloodplains. Within the framework of a multi-purposeuse of water facilities, fish management does notconflict with other users, on condition that during thedevelopment of the individual activities the basicecological principles are respected. These fishingmanagement measures are applied to streams onthe basis of a series of physical, chemical, biologicaland ecological parameters collected from variousindividuals and institutions.

It is recommended that in the fish stocking of theopen waters, spawning grounds should be included,for the economically more interesting species, at thelevel of the entire region. Such spawning areas existin Jelas polje, Jasinje, Poljana; a convenientspawning ground could be established by the Sava.The Ministry of Agriculture and individual anglingclubs have a permanent need for major quantities ofwild species (which can hardly be bought on themarket) and with respect to the outstandingopportunities of this area, we recommend the watermanagement institution that as part of ecologicaleducation programmes it help in the introduction ofwild fish spawning technology, as well as that foreconomically interesting fish, particularly pike-perchand carp. The spawned larvae of various speciesshould then be stocked in the branches and lakeareas alongside the mainstream, so that the youngcan in the end be released into the open streams.

In the various aquatic habitats, the endeavour shouldbe to create a fish population that will to the greatestpossible extent use all the food niches, whileindividual species and year classes will be reducedby angling.

It is practically impossible to work out a precise planfor stocking species, quantities and sizes of fish inthe optimum period capable of being valid over theyears. It most often happens that on the market thereis a shortage of suitable species in the necessarysize or quantity. In principle, on the market forfreshwater fish, only the economically moreimportant can be bought (common carp, grass carp,big head and silver carp, catfish and tench),

Some spawning areas deal with the spawning ofpike. The spawning of the pike-perch in practice iscarried out mainly with the transfer of pike-perchnests from open water.

The closing of sluices frustrates the passage of fishto the spawning grounds and the inflow of nutrientmater, which ultimately affects the whole food chain.According to the new Freshwater Fishing Bill, it isstrictly forbidden in any way to prevent the migratorymovement of fish to the floodplain and their return to




namjenu, svrhu i naèin korištenja retencije Mokropolje. Potrebno je izraditi pravilnik o naèinimaupuštanja vode, vremenu i trajanju vremena kad sevrlo pa�ljivo mora manipulirati pregradom. Plangospodarenja biološkim resursima, posebice ribom,najbolje æe se provesti ako se ostvari gotovo prirodnitijek trajanja poplava u Mokrom polju.

Razmatrano podruèje koristi se uglavnom za športskiribolov. Gospodarski ribolov na ovom podruèjudopušten je na ribolovnim podruèjima rijeke Savenizvodno od Siska. U podruèju djeluju brojnašportsko-ribolovna društva koja upravljaju vodamakoje su im dane na korištenje. Promatrano podruèjekoristi oko 10 - 15 000 ribolovaca.

Valja imati na umu da bogatstvo ribljih vrsta, kao iihtioprodukcija Lonjskoga polja nije primarnoekonomska kategorija. Velika ihtioprodukcija nu�naje za opstanak, brojnost i raznolikost velikoga broja�ivotinja koje tu �ive, primjerice vidre, velikihpopulacija i vrsta ptica, �aba, malih sisavaca,predatora itd. Daleko manje treba gledati na klasièneribarske uèinke proizvodnje konzumne ribe.

U zaštiti ribljega fonda odreðenu ulogu imaju imeðunarodna tijela. Dobra strana meðunarodnihstrategija zaštite riba ostvaruje se poštivanjemBernske konvencije, koja štiti europsku floru i faunu iprirodna staništa, te smjernica Europskoga vijeæa uvezi sa "zaštitom prirodnih i poluprirodnih staništa,kao i faune i flore”. Iste konvencije dovele su dopopisa staništa i uoèavanja skupina �ivotinja i biljakakojima treba zaštita.

Monitoring je veoma va�an u ribarstvu jer omoguæavaizraèunavanje moguæeg prinosa. Monitoring bi trebalozapoèeti sakupljanjem podataka od tradicionalnihribara, uz eksperimentalni izlov ovlaštenih institucija.Osnova monitoringa bilo bi praæenje stanja ihtiomase iinventarizacija bogatstva vrsta riba. Znanstvenipristup, koji ukljuèuje znanstveni rad na terenupromatranoga podruèja, nezamjenjiv je prioptimizaciji ihtiocenoza. Iz godišnjeg ulova mo�emoutvrditi masu èitavog ihtiofonda, kolièinu ribe kojaostaje za druge potrošaèe itd. Kod krivolova, opæenitouzevši, masa preostalih riba manja je od trostruke, akad slabog ribolova viša od peterostruke. Omjerizmeðu vrjednijih i manje vrijednih riba kod ulovaupuæuje na vrijednost fonda.

Kvalitetan program monitoringa mo�e se dati teknakon podrobnih istra�ivanja. Meðutim, opæeniti

11.2. Monitoring

the mainstream. A whole series of measures havebeen put forward in the matter of conditions forbuilding the Trebe� II sluice. In the watermanagement document the purpose, intention andmanner of use of the Mokro polje retention should bestated. It is necessary to draw up Regulationsconcerning the manner of releasing the water, thetime and duration when the sluice has to bemanipulated very carefully. The manner of managingthe biological resources, particularly the fish, will bebest carried out if the duration of the flooding inMokro polje is kept more or less to the naturaloccurrence of it.

The area under consideration is used mainly forangling. Economic fisheries in this area are allowedin the fishing areas of the Sava River downstreamfrom Sisak. In this area there are many angling clubsthat manage the water that they have been allotted.The area under observation is used by some 10 to 15thousand anglers.

It should be borne in mind that the richness of fishspecies, and the ichthyoproduction of Lonjsko Poljeis not primarily an economic category. Largeichthyoproduction is necessary for the survival,abundance and diversity of a large number ofanimals that live here, such as the otter, largepopulations and species of birds, frogs, smallmammals, predators and so on. It is necessary tolook much less at the classical fishery effects of theproduction of fish for the table.

In the protection of the fish stocks, a certain role hasto be played by international bodies. A good side ofinternational fish protection strategies is effectuatedby the observing of the Berne Convention, whichprotects European flora, fauna and habitats, and thedirectives of the European Council in connection withthe “protection of natural and semi-natural habitatsas well as of fauna and flora.” The same conventionshave led to the scheduling of habitats and theregistering of the groups of animals and plants thatneed protecting.

Monitoring is extremely important in fisheriesbecause it enables the calculation of the possibleyield. Monitoring should start with the collection ofdata from traditional fishermen, with experimentalcatches by authorised institutions. The basis of themonitoring should consist of the monitoring of thestate of the ichthyomass and the inventorisation offish species richness. A scientific approach,including scientific field work in the area, is essentialin the optimisation of the ichthyocoenosis. From the

11.2. Monitoring



53

modeli monitoringa moèvarnih i rijeènih ekosustavapostoje. Ovdje valja poseban naglasak dati trofijiekosustava, kao i posebnim vrstama koje dolazesamo u poplavnim nizinama. Uobièajena je metodapromatrati staništa i abundanciju vrsta kao

. To su kljuène vrsteza kakvoæu ovakvih ekosustava.

Na svim ribolovnim vodama treba ustrajati na voðenjuodgovarajuæe evidencije i na prikupljanju te obradistatistièkih podataka o slatkovodnom ribolovu.

Suradnju s okolnim puèanstvom treba odr�avati.Lokalno puèanstvo kljuèno je u otkrivanju nepoznatiha èesto prisutnih osoba ili vozila u parku i njihovopravovremeno prijavljivanje policiji ili èuvarskoj slu�biParka prirode. Zato treba naglasiti nu�nosteventualne edukacije kako bi se postiglo potpunosu�ivljavanje s ovim prostorom i upozorilo naopasnosti od krivolova i drugih nedopuštenihaktivnosti. Posjeæivanje je svakim danom sveizra�enije i osjeæa se nedostatak prikladnihsmještajnih kapaciteta za turiste u neposrednoj bliziniParka prirode, gdje veliku ulogu mo�e odigrati upravolokalno puèanstvo uvoðenjem seoskoga turizma.

Obavješæivanje i promid�ba lokalnog stanovništvava�ni su preduvjeti za dobru i kvalitetnu zaštitu. Upodizanju razine zanimanja veliku ulogu imajurazlièiti promid�beni materijali, prospekti, leci,naljepnice, popisi ugro�enih riba, popisi vrsta postaništima i slièno. Razvijanje svijesti o va�nostiribarstva osobito je znaèajno za mlaðe generacije. Uva�ne oblike aktivnosti ubraja se i prikazivanjefilmova i dijapozitiva posjetiteljima te struèna voðenjai edukacija, organiziranjem škola u prirodi.

Va�no je podizanje razine razlièitih oblika edukacije isvih sudionika u slatkovodnom ribarstvu.

Kako �upanijski ribarski inspektori, kao ni ribarskiinspektori Dr�avnog inspektorata, prema novom

Cyprinuscarpio, Leucaspius delineatus, Abramis balerus,Umbra krameri i Misgurnus fosilis

11.3. Suradnja s lokalnim puèanstvom

11.4. Obaviještenost javnosti

11.5. Inspekcijske i èuvarske slu�be

annual catch we can determine the mass of thewhole fish stock, the quantity of fish remaining forother consumers and so on. In poaching, consideredgenerally, the mass of fish remaining is less thanthree-fold, and with weak fishing, more than five-fold.The ratio between the valued and the less-valuedfish in a catch indicates the value of the stocks.

A quality monitoring programme can be establishedonly after detailed investigations. However, generalmodels for the monitoring of wetland and riverineecosystems do exist. Here the main emphasis needsto be given to the trophic state of the ecosystems andto particular species that are found only in lowlandfloodplains. A common method is to observe thehabitats and abundance of species such as

. These are thekey species for the quality of such ecosystems.

In all fishing waters, the keeping of the properrecords and the collection and processing ofstatistical data on freshwater fishing have to beinsisted upon.

Collaboration with the local population must bemaintained. This local population is crucial for thedetection of unknown but frequently present personsor vehicles in the park and their being promptlyreported to the police or warden service of theLonjsko Polje Nature Park. And so it is necessary toemphasise the important of education so as toachieve total identification with the area and to warnof the dangers of poaching and other illegal activities.There are greater numbers of visitors every day, andthe lack of suitable accommodation facilities forguests in the immediate vicinity of the Park can beincreasingly sensed; here, a major role can beplayed by the local population through theintroduction of farmhouse tourism.

Public relations with and information of the localpopulation are vital conditions for qualityconservation. In raising the level of interest, a greatrole can be played by various forms of PR material,brochures and fliers, stickers and lists of endangeredfish, lists of species according to habitats and so on.The development of awareness of the important offishing is particularly important for the young. Also

Cyprinuscarpio, Leucaspius delineatus, Abramis balerus,Umbra krameri and Misgurnus fosilis

11.3. Collaboration with the localpopulation

11.4. Public information




Prijedlogu Zakona, nemaju ovlast nadzora u parkuprirode, nadzor nad ribolovnim aktivnostima na ovompodruèju trebali bi provoditi inspektori Dr�avneuprave za zaštitu prirode i okoliša. Problemi èuvarskei inspekcijske slu�be slièni su, dakle, kao i u ostalimparkovima prirode. Ribarstvo je u organizacijiSlatkovodnog ribarstva Hrvatske imalo reguliranupravnu osnovu, no ona je, prelaskom nadle�nostiribarstva u zaštiæenim podruèjima pod Zakon o zaštitiprirode, postala nefunkcionalna. Uoèljiv je manjakljudi, nepostojanje ribarsko - gospodarskih osnova,krivolov je razvijeniji nego na drugim podruèjima itd.Bit je u tome da se ribarstvo u parkovima prirode, podpritiskom velikog broja športskih ribièa i domaæegstanovništva, prakticira na ni�oj znanstvenoj razini odone uobièajene na ostalim vodama. Razvijanjenadzornièke slu�be sve je neophodnije radi što boljezaštite na terenu. Nadzornici u tom smislu mogu bitiaktivni èuvari i provoditelji Pravilnika o unutarnjemredu, vodièi skupina, edukatori i voditelji ekoškola.Isto tako mogu pru�iti znaèajniju tehnièku potporu priterenskim istra�ivanjima (sakupljanje uzoraka vode,tla, biljaka ili pojedinih skupina �ivotinja). Nadzornicise mogu koristiti i u pojedinim programima praæenja uparku pri èuvanju prostora od ribokradica.

important activities are the showing of films andslides to visitors, as well as qualified guide servicesand education, the organisation of nature-schools.

The raising of the level of various forms of educationof all those involved in freshwater fishing is of greatimportance.

Since neither the county nor the central governmentfishing inspectors, according the Bill, have anyauthority to carry out their work in the nature park,control of fishing activities in this area has to becarried out by inspectors of the NationalAdministration for Nature and EnvironmentProtection. The problems of warden and inspectionservices are the same as in other nature parks ofcourse. Fishing as organised by the CroatianFreshwater Fisheries had a regulated legal basis,but this, when the authority was transferred underthe nature protection law, ceased to function. Ashortage of personnel can be observed, the absenceof fishing management rules, and poaching is morecommon than in other areas. The essence of thematter is that fishing in the nature parks is undergreat pressure from both anglers and the localpopulation, and is practised at a scientific level that islower than in other waters. The development of acontrol service is increasingly essential for the sakeof protection in the field that is as effective aspossible. In this sense, the superintendents can bethe active keepers and implementers of the InternalOrder Regulations, the educators and guides of theeco-schools. Similar ly they can provideconsiderable technical support in field research(collecting samples of water, soil, plants andindividual groups of animals). The superintendentscan be used in individual programmes of monitoringin the park in the protection of the area against fish-poachers.

11.5. Inspection and warden services



55

12. LITERATURA/ LITERATURE

Ackermann, W.C. (1973): Man-made lakes: their problems and environmental effects. GeophysicalMonograph 17, Am. Geophysical Union, Washington

Appelberg, M., Degerman, E., Nyberg, P. (1989): Species composition and relative abundance of the fishfauna in acidified and limed Swedish lakes. Submitted to "Acid rain and the environment", Ed:J.Longhurst. The Acid Rain Information Centre, Manchester, U.K.

Balon, E.K. (1967): Evolution of the Danube River ichthyofauna, its recent status and an attempt to predictthe changes after the dam-power plant construction. Biološke prace (Bratislava) 13: 5-121 (In Slovak)

Balon, E.K. (1975): Reproductive guilds of fishes: a proposal and definition. J. Fish. Res. Board Can. 32:821-864

Balon, E.K. (1990): Epigenesis of an epigeneticist: the development of some alternative concepts on theearly ontogeny and evolution of fishes.. Guelph Ichthyol. Rev. (1):1-48.

Balon, E.K. (1990): Epigenesis of an epigeneticist: the development of some alternative concepts on theearly ontogeny and evolution of fishes.. Guelph Ichthyol. Rev. (1):1-48.

Banarescu, P. (1964): Pisces-Osteichthyes. Fauna Republici Pop. Romine 13. Acad R.P.R. Press, Bucarest.961 pp (In Rumanian)

Biro, P. (1977): Effects of exploitation, introductions, and eutrophication percids in Lake Balaton. Journal ofthe Fisheries Research Board of Canada 34, 1678-1683

Botnarius, N. (1967): Some characteristic features of the floodplain ecosystems of the Danube.Hydrobiologia, 8: 39-49

Descy J.P., Empein A., (1984): Meuse. In: Whitton B.A.(ed) Ecology of European Rivers. Blackwell Scientific,Oxford, 1-12.

Hefele, F. (1889): Nješto o ribah. Tiskarski zavod “Narodnih novinah”, Zagreb

Holèik, J. (1998): Impact of the Gabèikovo water works construction and operation on the recreational fisheryin the Slovak segment of the Danube river. Fisheries management in the Danube river basin, Galati, 64-65

Holèik, J., Bastl, I. (1976): Ecological effects of water level fluctuation upon the fish populations in theDanube river floodplain in Czechoslovakia. Acta Scientiarum Naturalium, Brno 10, 46 pp.

Holèik, J., Bastl, I., Ertl., M., Vranovsky, M. (1981): Hydrobiology and ichthyology of the CzechoslovakDanube in relation to predicted changes after the construction of teh Gabcikovo-Nagymaros river barragesystem. Pr.Lab.Rybar.Hydrobiol., 3: 19-158

Holèik,J. (1988):Effects of hydraulic engineering on habitat and fish community in river anabranches of themiccle Danube. In: W.L.T. van Densen, B. Steinmetz & R.H. Huges (Eds). 1990. Management offreshwater fisheries. Proceedings of a symposium organized by the European Inland Fisheries AdvisoryCommission, Goteborg, Sweden, 31 May-3 June 1988. Pudoc. Wageningen. pp 14-24

Holmlund, C.M., Hammer,M. (1999): Ecosystem services generated by fish populations. EcologicalEconomics 29(2): 253-268.

Mediæ , M. (1901): Ihtiološke bilješke. Rad Jugoslavenske akademije Znanosti i umjetnosti, Knjiga CCVI(Zagreb), Hrvatska.

Mero, D., Patriche, N., Billard, R. (1998): Les pecheries d'esturgeons dans le Danube Roumain entreIsaccea et Calarasi. Fisheries management in the Danube river basin, Galati, 45-46

Mrakovèiæ , M., Kerovec, M., Schneider, D. & Mišetiæ , S. (1997): Ichthyofauna of the lower part of the riverNeretva. Ninth international congress of European ichthyologists (CEI 9), Trieste, August 24-29, 1997.

Vasilescu, G. (1998): The influence of the anthropic impact on the ichthyofauna from the upper sector of theRomanian Danube. Fisheries management in the Danube river basin, Galati, 72-73

Williams, C.B. (1964): Patterns in the Balance of Nature. Academic Press, London




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