Suciu R. Present and perspectives of sturgeon conservation in the LDR …awsassets.panda.org/downloads/31_2009_presentation... · 2015. 2. 17. · PRESENT AND PERSPECTIVES OF STURGEON

PRESENT AND PERSPECTIVES OF STURGEON CONSERVATION

IN THE LOWER DANUBE RIVER, ROMANIA

Suciu R. *, Knight C.M.**, Onara D.F*., Paraschiv M.*, Taflan E.*, Iani M.*, Holostenco D.*

* Sturgeon Research Group /Danube Delta National Institute (DDNI), Tulcea, Romania

**Norwegian Institute of Water Research (NIVA), Oslo, Norway

Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009


Outline:Why conservation measures?

Goals of conservation and recovery program

Conservation regulation of May 2006

Preserving genetic diversity

First recaptures and post stocking evaluation

Perspectives

Discussions

News on ongoing projects


Why conservation measures ?

- Option to recover: “build up of stocks by hatchery production and return brood stock to home system”

(Cowx 1999)

1990-1999 :10 years of intensive and uncontrolled fishing(Navodaru et. al. 1999)

Arguments: - decline of catches - disrupted age class structure- poor / lacking natural recruitment

•stellate sturgeon severely suppressed•Russian and beluga sturgeon - relict status facing extinction by Alee effect (Alee 1931)


Example of Alee effect: Recession and extinction of European sturgeon (Acipenser sturio) from rivers of Western Europe

■ Catches of European sturgeon in the Lower Elbe River during 1890 – 1918 (Kinzelbach, 1997). Note that extinction occurred during only 10 years (1909 - 1918)


Decreasing of catches:A. güldenstädti (1920 - 2005)

Catches of Danube sturgeon recorded in Romania during 1920 - 2005

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Year

[tons

]


Decreasing of catches:H. huso (1920 - 2005)

Catches of beluga sturgeon recorded in Romania during 1920 - 2005

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Anul

[ton

e]

Iron Gates I

No data

Iron Gates II


Decreasing of catches:A. stellatus (1920 - 2005)

Catches of stellate sturgeon recorded in Romania during 1920 - 2005

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40

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[tons

]

Under-reporting of catches


0

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2000025000

3000035000

40000 [Kg]

2002 2003 2004 2005Year

Sturgeon landings - Romania - 2002- 2005

Beluga sturgeonDanube SturgeonStellate sturgeonTotal [Kg]

37 tons

29 tons

17 tons 11 tons

Sturgeon catches in Romania (2002 - 2005)


Methods: (1) Age determination Pectoral bony fin rays collected by professional fishermen

cross-sections


• stellate sturgeon (A) cohort consists mainly of first time spawners (6 – 8 years old) • Russian sturgeon (B) and beluga sturgeon (C&D) clearly lack first time spawners

Age class structure (2003 - 2004):

0

5

10

15

20

25

14 15 16 17 18 19 20 21 22 23 24

Age [years]

frequ

. %

(N landed = 97; N sampled = 25)C

(N captured = 344; N sampled = 137)

05

10152025

3035

5 6 7 8 9 10 11 12 14 18

Age [years]

freq

u. [%

A

0

5

10

15

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25

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35

15 16 17 18 19 23 27Age [years]

Freq

. [%

]

( N landed = 29; N sampled = 12 )B

( N landed = 62; N sample = 22)

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16 17 19 20 21 23 24

Freq. [%]

Age [years]

D

Stellate sturgeon males (2003)Russian sturgeons / mixed sexes (2003)

beluga sturgeons / mixed sexes (2003) beluga sturgeons females (2004)


(2)Catching larvae in the RiverFishing with drift nets set at 12 – 15 m depth in the Danube River, downstream of potential spawning sites, in years 1999, 2004, 2007 and 2008, we collected six Acipenser (?) / Huso (?) larvae (Paraschiv et al. 2007).

April 28, 2007 Danube River Km 310

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

bp

1500

850

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50

Identification of larvae captured in the Lower Danube River (1999 - 2008)

(Onara 2008) using cytochrome b region of mt DNA cut with MseI)

A d u l t s L a r v a e

R e f e r e n c e s a m p l e s

May 29, 1999

May 2, 2008

May 20-21, 2004

Apr. 28, 2007

husoruthenusstellatus güldenstädti


Methods:(3) Bottom drifting trammel net to capture YOY

(90 x 1.8) m , 20 mm mesh size


Beluga sturgeon- Huso huso

0123456789

101112

2000 2001 2002 2003 2004 2005 2006 2007Year

CPUE

Russian sturgeon - Acipenser gueldenstaedti

0

0.1

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0.8

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CPUE

Stellate sturgeon - Acipenser stellatus

00.2

0.40.6

0.81

1.21.4

1.6

2000 2001 2002 2003 2004 2005 2006 2007

Year

CPUE

Sterlet - Acipenser ruthenus

02468

10121416

2000 2001 2002 2003 2004 2005 2006 2007Year

CPUE

Natural recruitment in the Lower Danube River (2000 – 2007)Juvenile index (Paraschiv et al. 2007)


Conservation regulation of May 2006

• Migratory Fish Monitoring Station (Isaccea, Danube River km 100)

•joint Ministerial Order (May 4, 2006):- conservation of wild sturgeon populations / stocks - development of sturgeon aquaculture in Romania

•allows only the capture of brood fish from the wild (special authorization) for artificial propagation:

- supportive stocking of the Danube River -development of sturgeon aquaculture

•use non-destructive artificial propagation procedures

•release PIT tagged wild brood fish back in the Danube River


Goals of the conservation and sustainable use program (Suciu et al. 2007)

•Prevent population extinction

•Preserve genetic diversity of populations / stocks

•Rebuild natural age class structure by implementing of Supportive Stocking Program (SSP)

•Restore natural recruitment

•Develop sturgeon aquaculture to lower market pressure on wild populations / stocks


Structure of Supportive Stocking Program:•catch and PIT tag of wild brood stock in limited number of sites (2) and time ( 15.02 – 15.04)•use minimum effective annual number of brood fish•apply non-destructive artificial propagation procedure

•apply fertilization scheme to maximize genetic variability

•release all spent brood fish back in the Danube River

•grow offspring separately in families to a TL ≥ 15 cm•tag all young sturgeons individually using CWT•stock young sturgeons close to catch sites of brood fish•monitor survival in the DR and the Black Sea costal waters

•conduct post stocking evaluation


Capturing of wild adult sturgeons(Suciu et al. 2007)

Fishing of live wild adult sturgeons permitted only in two locations:

* Km 120 - 130 (downstream of Grindu)* Km 40 – 48 (on the Borcea branch)

Fishing sites - surveyed day and night by the FisheryInspection to: prevent illegal catch

PIT tag the fish

Give a chance to all other sturgeons to spawn naturally in the river.

Bulgaria

Romania

Serbia

Ukraine

BlackSea

Iron Gates I (1974)

Iron Gates II (1984)

Danube River

Tulcea


Catching and tagging wild adult sturgeons• All brood-fish captured live and immediately PIT tagged,

transported to hatcheries - kept in covered concrete tanks. • All PIT serial numbers – recorded - data base at

NAFA Romania.• Clip fins were sampled for later DNA analysis in DDNI lab.


Preserving genetic diversity: (i) minimal effective number of brood fish + multiple male fertilizing

Sperm was extracted with a silicon tube attached to syringes -kept on ice for “multiple male” fertilization

Ovulation - induced using Nerestin - synthetic product with soft action - avoids over – maturation of brood fish.

Eggs - obtained by stripping after a minor internal incisionin the ovarian duct


YOY grown in families and tagged individually - CWT(Paraschiv et al. 2008)

Tags injected alternatively in right /left pectoral fin (2005 / 2006)


Stocking the Danube River

• data base with CWT serial numbers of young sturgeonsstocked from each family was established at DDNI andNAFA Romania.

• artificially produced young sturgeons - stocked closeto locations where their parents were captured


Preserving genetic diversity:(ii) Releasing of wild brood fish after artificial propagation

•172 wild sturgeons - captured in year 2007 for SSP:16 – beluga sturgeons; 5 - Danube sturgeons88 – stellate sturgeons; 60 - sterlets

•After artificial propagation 169 – released back in the Danube River


Preserving genetic diversity:(iii) cryopreservation of sperm (Suciu et al. 2008)

- to enable multiple male fertilisation in species lacking brood fish (A. güldenstädti) – cryopreservation of sperm was applied for the first time in May 2007 at Isaccea hatchery

-Sturgeon sperm bank - 24 ml of high quality sperm from: 2 stellate sturgeons1 sterlet 2 Russian sturgeons


Preserving genetic diversity:(iv) preserve rare genotypes

(Onara et al. 2007)

RFLP of mtDNAregions ND 5/6 and Cyt b

A. stellatus brood fish having rare ND 5/6 (II - VI) and Cyt b (II - III)haplotypes migrate in the Danube in early spring

Their spawning grounds are more distant from the seaand therefore were historically more vulnerable to the fishery

To preserve the genetic diversity of A. stellatus rare mtDNA genotypes should be used in SSP separately


Duration of SSP:Until full restoration of natural recruitment and rebuilding of natural age class structure butNOT longer than 10 years

YOY stocked into the Danube River (2005 - 2008)Year Huso huso A. gueldenstaedti A. stellatus

[No. of specimens] Mean [No. of specimens] Mean [No. of specimens] Mean TW [g] TW [g] TW [g]

2005 2 500 235 7 800 33 2006 12 500 123 Ø 53 000 282007 15 000 345 96 500 96 2008 20 000 142 40 000 213 25 000 35 Total 47 500 139 000 85 800

Cost of SSP: ≈ 1 million € / year


Survival of tagged juveniles• During experimental fishing to monitor natural recruitment, in June –

Sept 2007 seven CWT tagged stellate sturgeons were captured at Danube R. Km 119 and 100.

• Each fish had CWT tags in their left pectoral fin, showing that they were tagged and released in December 2006 on the Borcea branch (Km 39).


First post stocking evaluation (June - Sept 2007)

Average TL of stellate sturgeon recaptured after: 6 month 37.75cm8 month 43.18 cm

i.e. growth rates of 3.27 - 3.45 - cm / month

Average TL of stellate sturgeon at release (Dec. 2006): 17 cm

Average annual growth rate recoded in white sturgeonsstocked in the Kootenai River was 6.4 cm / year (Ireland 2002)

June 5, Danube Km 119


Discussion:

Difficulties:

• in some years insufficient number of brood fish of Russian sturgeon • deficient enforcement of regulations (3 governments in just 3years)• illegal fishing / poaching of sturgeons still present •Monitoring Center Isaccea of DDBRA still not operational

Weaknesses of SSP:

• in some years stocking delayed due to difficult public acquisition process of young sturgeons (improved in 2009)

• lack of involvement of local fishermen communities• survival evaluation survey still missing• fall migrants still not propagated separately

Satellite telemetryMay 2009 – for the first time on the Danube River and in Europe

Ongoing projects: Best Combat (RO & NO)

Satellite telemetryArgos satellite - first locations of tagged beluga in the Black Sea

10.08.2009 / 75d

St. George

Chilia delta

30.07.2009 / 65d

DIDSON camera

First Dual Frequency Identification Sonar (DIDSON - € 75,000) in Romania & lower Danube River

Dan Ericson / USA Kate Hawley / NIVA- No

Marian Iani / DDNI - Ro

DIDSON

viewing large fish in deep & turbid water/ Danube River

Acoustic telemetry(Oct. – Nov. 2009)


Perspectives:

JOP Black Sea (2010 - 2012): All Black Sea survey (CWT) of survival and distribution of young sturgeons stocked in the Danube River (2005 -2009) (TR, BG, RO, UA & GE)

BestCombat project (2009 - 2011): (i) present and ancient genetic diversity in beluga sturgeon - microsatellite and mtDNA genes; (ii) location of essential spawning and wintering habitats in the river using up to date acoustic telemetry and DIDSON camera; (iii) finalizing survey of movements and distribution in the sea using satellite transmitters.

Improving SSP (2010 - 2015): (i) propagate fall migrants separately; (ii) avoid late stocking during the year

Assist NAFA to improve regulation enforcement (2010 - 2015): (i) involving local fishermen communities; (ii) include in long-term contracts with private hatcheries

guarding of fishing sites


Acknowledgments:

Research funded by projects:

DanStur (348,000 € / 2006 - 2008 ) – project 120 / 2006 - CEEX Programme - Romanian Research Agency

BestCombat (1.234 million € / 2009 - 2011) – project 112231 / 2009 - Norwegian Cooperation Programme for Bulgaria and Romania (85%) and Romanian Ministry of Environment (15%)

The authors are grateful to Marilena & Dumitru Maereanuand to Robert Radutafor providing the fish and logistical assistance for the satellite telemetry

and to Fishermen Association Fetestifor assistance in capturing beluga sturgeons for acoustic telemetry

THANK YOU VERY MUCH FOR YOUR ATTENTION!

Documents

Suciu R. Present and perspectives of sturgeon conservation in the LDR …awsassets.panda.org/downloads/31_2009_presentation... · 2015. 2. 17. · PRESENT AND PERSPECTIVES OF STURGEON