Rafkesque, nom Round Lake and mature Winnipeg River · 2004-09-01 · Feeding ecology and community structure - - Growth and Feeding of other fishes in Boreal Systems -- Perth, walleye,

Growth estimates, habitat use, and ecology of the lake sturgeon, Acipenser

fulvescens Rafkesque, nom Round Lake and mature reservoin in the Winnipeg River

by

DAVID BLOCK

A Thesis Submitted to the Faculty of Graduate Studies

In Partial Fulfillment of the Requirements For the Degree of

MASTER OF SCIENCE

Department of Zoology University of Manitoba

Winnipeg, Manitoba

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GROWTH ESTIMATES, HABITAT USE, AND ECOLOGY OF THE LAKE STURGEON, Acipenserfiivescens Mnesque , FROM ROUND LAKE AND MATURE RESERVOIRS IN THE

WINNIPEGRIVER

BY

DAVID BLOCK

A Thesis/Practicum submitted to the Faculty of Graduate Studies of The University of

Manitoba in partial fulfillment of the requirement of the degree

of

MASTER OF SCIENCE

DAVID BLOCK O 2001

Permission hrrs been granted to the Librnry of the University of Manitoba to lend or sel1 copies of this thesis/practicum, to the National Library of Canada to microfilm thW thesis and to lend or sel1 copies of the film, and to Univenity Microfiims Iic to publirh an a b s t m t of thb tksidprieticum.

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Growth, population estimates, density, and distibution of lake sturgeon were

compared arnong a ptïstine system and two mature reservoirs. Round Lake is a small

unperturbed lake on the east side of Lake Winnipeg. The Winnipeg River contains a

series of mature reservoirs between the Ontario border and Lake Winnipeg. Two sections

of the river (Sevens Sisters-Slave Falls, Slave Falls-Pointe du Bois) were selected to

study. Movements and habitat use of lake sturgeon in Round Lake were studied and the

food items of the fish species in Round Lake were collected and compared to historical

records of lake sturgeon food habits. Lake sturgeon growth was not simcantly different

between the three study sites. Distribution in the Seven Sisters-Slave Falls system was

related to alterations in flow. High densities were found in the sections of the river that

are still flow of the river. Density was low or zero in sections with altered flows in the

Seven Sisters area but not in the Slave Falls-Pointe du Bois system. Distribution in Round

Lake was also related to fiow. The highest densities were in the vicinity of the inlet and

outlet where flow is higher.

Lake sturgeon are generally believed to be bottom dwellers but movement studies

revealed that they spend extensive amounts of t h e in the water col- above the

bottom. Movements were related to areas of current at the inlet and outlet and dong the

contours of the riverbed -ng through the lake. Although 1 1 substrate types were

identified in Round Lake, lake sturgeon, when in contact with the substrate, generally

tended to select fine sand and medium sand substrates.

The analysis of stomach contents of six species of fish nom Round Lake indicates

that Ephemeridae are the most important food item in terms of both abundance and

occurrence. Lake sturgeon are known to feed on Ephemeridae in many systems therefore

overlap is assumed with some of the species of fish fiom Round Lake.

ACKNOWLEDGEMENTS

1 would like to thank numerous people who helped make the completion of this

thesis possibIe.

First and foremost 1 would like to thank my advisor Dr. Terry Dick. Leading by

example, he has shown me the Unportance of a good work ethic and a strong desire to

l em. Over the last five years we have discussed everything h m science, history, and

art, to movies, books and gardening. I have certainly taken away fiom this expenence

more than a better understanding of the lake sturgeon.

I thank my advisory commitîee, Dr. Abrahams and Dr. Papst, for their input and

insights during my thesis.

I would also like to thank Mingchaun Lu who, in his own unique way, solved al1

my computer problems as well as helping with any miscellaneous lab problems.

I acknowledge the help of Jim Beyette and Keith Kn'stofferson, Manitoba Natural

Resources, for their help with the project.

1 would like to tbank my Wends and family. My mother, father and sister have

always been supportive and helped guide me through the many decisions required to

complete such a task.

Finally, my wife, Sheri, who has provided invaluable moral support whether it be

listening when 1 needed to rant or pushing me in the right direction when I was heading

off track.

Table of Contents

Abstract - Acknowledgements List of Tables - - List of Figures -- List of Appendices --

Generd Introduction -- Objectives -O --

Literature Review Lake Sturgeon - - -

History of the fishery - Biology and life history ---- a

Movements and Habitat Selection - Lake Sturgeon - - Other sturgeon species -

Growth --- ---- Hydroelectric development and sturgeon --- - Acoustic telemetry -------------- Feeding ecology and community structure - - Growth and Feeding of other fishes in Boreal Systems --

Perth, walleye, and sauger --------- Pike - ------HI--

Mooneye ---- Suckers (white and redhorse) --

Chapter 1 - Biological statistics of lake sturgeon in Round Lake and The Winnipeg River

v i vii

X

Chapter 2 - Movements and habitat utilkation of lake sturgeon in Round Lake

Introduction - - Materials and Methods -

Depth and Substrate Hardness Sediment Analysis mur

Acoustic telemetry Telemetry data --

Results - Substrate and Depth p-

Movements -- o p

Discussion -- Chapter 3 - Diet and growth of the fish species of Round Lake

Introduction ------ - rrm

Materials and Methods -- -O-

Field Sampling --- Stomach content analysis -- Fish Aging Methods -- -uI.-LI---

ResufB n

Discussion --- -III-

General Surnmary --- - vu---

Literature Cited -------- - .------ -0

Appendices - CI -II-wIu

Table 1.

Table 2-

Table 3.

Table 4.

Table 5 :

Table 6:

Table 7:

Table 8:

Table 9:

Table 10:

Table 1 1 :

List of Tables

Lake sturgeon food habit data from the literature

Studies and locations of lake sturgeon growth -- Von B e r t a l m growth parameters for Round Lake, Seven Sisters-Slave Falls, Slave Falls-Pointe du Bois, and the 17 data sets presented in figure 2 - Population estimates for lake sturgeon in Round Lake, Seven Sisters-Slave Falls, and Slave Falls Pointe du Bois

Lake sturgeon data table for Round Lake, Seven Sisters-Slave Falls, and Slave Falls-Pointe du Bois -- Sediment grabs taken from Round Lake in 1997 and 1998 - Sediment classification scheme for Round Lake. Classifications were based on a comparison of sonar and sediment grab data

Lake stwgeon data for acoustic tagged fish -- O--

Abundance of prey items in the stomach contents of yellow perch, Walleye, sauger, mooneye, pike, and shorthead redhotse, and Overall abundance and occurrence values -- O--O-

Al1 families of invertebrates prey found in the stomach contents Of fish fiom Round Lake ------------

Schoener's (1970) index of diet overlap and LeWi's (1968) index Of diet breadth for yellow perch, walleye, sauger, mooneye, pike,

List of Figures

Figure 1.

Figure 2-

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

North Amencan distri'bution of lake sturgeon- Hatched area outlines the greatest extent of the distribution _- C o m ~ * s o n of lake sturgeon age-length data reported fiom the literature -

a; Growth of yellow perch in Lake Winnipeg Wajkov 1930), Lake of the Woods (Carlander 1950), and Weber Lake, WI (Schneberger 1 935) b; Growth of sauger in Minnesota (Van Oosten 1948), Lake of the Woods (Carlander 1950), and Manitoba (Bajkov 1930) c; Growth of walleye in Lake Manitoba (Bajkov 1930), Marie Lake, AB (Craig and Srniley 1986), and a rnean for Canada (Carlander 1997) ------

a; Growth of mooneye in Lake Erie (Van Oosten 196 1) and the Assiniboine River (Glenn 1975a) b; Growth of the white sucker in Lake of the Woods (Chambers 1963) c; Growth of the shorthead redhorse in the Saskatchewan River (Scott and Crossman 1973) - -- Map of the Pigeon River fiom Family Lake to Lake Winnipeg

Map of the Winnipeg River fiom the Manitoba Ontario border to Lake Winnipeg ---- ---

Locations of lake sturgeon populations compared for growth rates using analysis of covariance. Sites 1-3 are Round Lake, Seven Sisters Slave Falls, and Slave Falls-Pointe du Bois respectively. Sites 3- 20 correspond to the data sets in Appendix 2.--------

Map of Round Lake designating blocks 1 to 4 used for lake sturgeon sampling - -----

Figure 9.

Figure 10.

Figure 1 1.

Figure 12.

Figure 2 3.

Figure 14.

Figure 15.

Figure 16.

Figure 17.

Figure 18.

Map of the Seven Sisters-Slave Falls region of the Winnipeg River designating blocks 1 to 12 used for lake sturgeon Sampling -- --

Map of the Slave Falls-Pointe du Bois region of the Winnipeg River designating blocks 1 to 4 used for lake sturgeon sampling - -

Graph of age vs length for lake sturgeon in Round Lake, Seven Sisters-Slave Falls, Slave Falls-Pointe du Bois, Lake Wimebago (Priegel 1973),Sipiwesk Lake (Sopuck 1987), La Grande River (Magin 1977), and the Saskatchewan River (Haugen 1969)

Mean weight cornparisons of lake sturgeon between sections in each study site and between overall means of each study site. Horizontal line indicates overall mean of ali sections combined. Sections with the same letter were not significdy different (Tukey's test, p0.05) ---

Age fkequency cornparison of lake sturgeon for all three systems - ---I-UIIIIII-

Age fkequency distribution of lake sturgeon for three time periods for Seven Sisters-Slave Falls -------

Round Lake depth contours (lm), location of 37 sediment grabs taken in 1997 (A-H) and1998 (1-27), and the locations of the two buoy amys used for acoustic telemetry ---------

Hardness rnap of Round Lake with depth contours. Values range from 95(lightest brown) to 150 (darkest brown) ---

Depth selection of large (LS4009, LS4O 14, LS4O 15, LS4016, LM0 16, LS4017; 67908 - 16900g) and small (LS4010, LS4011, LS4012, LS4013; 506g - 632g) lake sturgeon in Round Lake ---- __-_--

Figure 19. A) Depth selection of al1 9 lake sturgeon. B) Swimming depth of the three lake sturgeon tagged with depth tags. C) Swimming depth of lake sturgeon when in contact with the substrate. D) Depth availability of substrate in Round Lake 98

Figure 20. Substrate selection of lake sturgeon and substrate availability in Round Lake - - 100

Fi-we 2 1. Age-length of yellow perch, walleye, and sauger- 115

Figure 22. Age-length of mooneye, white sucker, and shorthead redhorse in Round Lake 117

Figure 23. The composition of fish species in Round Lake, Seven Sisters-Slave Falls, and Slave Falls-Pointe du Bois - 1 19

Figure 24. Multiple descriminant analysis of four species of fish from Round Lake ------- 125

List of Appendices

Appendix 1 Convention on International Trade in Endangered Species listings for the family Acipenseridae - 162

Appendix 2 Lake sturgeon age-length data for the study sites in figures 2 and 7 - 165

Appendix 3 Movements of lake sturgeon in Round Lake in July and August 1997 using acoustic telemetry (Begout-Anras et al) 169

Appendix 4 Movements of lake sturgeon in Round Lake in 1996, 1997, and 1998 using radio tags - 171

GENERAL INTRODUCTION

A fiagmented and diverse literature ranging fiom published research studies to

popular articles to a gray literature, much of which was in the form of government or

consultant reports was reviewed by Dick and Choudhury (1992). It was clear fiom this

review that even with the ciramatic decline in Iake sturgeon populations almost a century

ago there were considerable gaps in the knowledge of lake sturgeon biology. Based on

the curent lake sturgeon populations these gaps in knowiedge are dificuit to fiIl because

no where in North Amenca are sturgeon populations near their historical highs nor are

many of the remaining renvrant populations fiom aquatic systems comparable with their

historical ecological conditions. There is one viable lake sturgeon population in the Lake

Wimebago system, Wisconsin, where sturgeon populations are manageci for a wher

spearing sports fishery. The overall sturgeon biomass is high in this system but the lake is

highly perturbed due to anthropogenic factors (Choudhury et al 1996, Carney and Dick

2000). Consequently, there are few places in North America where anything close to a

'natural' system exists for lake sturgeon: ie. absence of sturgeon exploitation (pst or

present) and absence of commercial and sports fishing of other fish species, free fiom

pollution, and other foms of habitat degradation.

This study was undertaken to detemine if a relatively pristine population of

sturgeon existed in western Canada and if so wuld it be used to better understand the

biology of lake sturgeon relative to other fish species and to its habitat requirements.

Objectives

The overall objective of this thesis was to study the biology and population

structure ofjuvenile and adult lake sturgeon in an unperturbed (the isolated Round Lake

population) and pemubed (hgmented populations in the Winnipeg River) environment.

Specific objectives were to begin to understand: 1) how lake sturgeon utiîize their

environment, especially as defined by substrate, rivernalce bathymetry and flows and 2)

the interrelationships between lake sturgeon and other fish species conceming food items

consumed and relative population nwnbers. The specific objectives are a difficult task as

there are few unperturbed fish communities in North America containing lake sturgeon.

A sturgeon population that represents a smaiî unpemirbed population is faund in Round

Lake on the Pigeon River, in Manitoba. Unfomuiately it is extremely vulnerable due to

the low number of reproducing adults. The sturgeon populations in the Winnipeg River

have been closed to al1 fishing since 1941 and are Iikely one of the best examples in

North America of the current situation in mature reservoïrs fiom a historically very

productive sturgeon river system.

IXIXRATURE REVIEW

Lake Sturgeon

The order Acipenseriformes, belonging to a group of basal Acthopterygian fishes

(Choudhury and Dick 1998), has two living families (Acipenseridae and Polyodontidae),

6 genera, and 26 species worldwide (Nelson 1994). The Acipenseridae are old with the

fossil record of sturgeon like fish dating back 100 miilion years to the upper Cretaceous

(Harkness and Dymond 196 1, Fogle 1975, Pearce 1986, Mecozzi 1988, Choudhury and

Dick 1998). Fossils of an extinct family, the chondrosteidae, are dated fkom the lower

Jurassic to the lower Cretaceous (Scott and Crossman 1973). Other authors state that

sturgeon are primîtive relicts of the Devonian period 300 million years ago (Glover 1 96 1,

Ono et al 1983, Houston 1987). Choudhury and Dick (1998) suggest that acipenserids

diversified within a narrow time m e and lapsPd into a subsequent long period of

morphoIogica1 stasis. The family Acipenseridae is described as having an elongate body,

subcylindrical, with five rows of bony scutes, 1 dorsal, 2 lateral, and 2 lateroventral; skin

appears naked but has small patches of denticles; head is covered in bony plates; inferior,

protractile, toothless mou& preceded by four barbels; heterocercal tail; unpaired fins are

preceded by fblcra; the k t ray of the pectoral fin is ossifie& large simple air bladder

with free communication to the esophagus; spiral valve; cartilaginous skeleton (Kirsch

and Fordice 1889, Harkness and Dymond 1961, Scott and Crossman 1973, Houston

1987).

The lake shirgeon has the most local names of al1 North Amencan sturgeon

species. These narnes include: rock, cornmon, red, ruddy, Ohio, stone, shell-back, bony,

fkeshwater, smooth-bac& abbernose, black, dogface, bull-nosed and Great Lakes

sturgeon (Harkness and Dymond 196 1, Williams and Vondett 1962, Scott and Crossman

1973, Ono et al 1983, Pearce 1986, Mecozzi 1988).

The origînai distribution of lake sturgeon was extensive (see maps in Dick and

Choudhury 1992) as they were found in the Mississippi, Great Lakes-St. Lawrence, and

Hudson Bay drainages (Harkness and Dymond 196 1, Scott and Crossman 1973). Few

fkeshwater fish have a wider geographic range (Harkness and Dymond 1961). Figure 1

(modified from Dick and Choudhury 1992) shows the original North American range.

Harkness and Dymond (196 1) descnkd the original range as follows; lake shirgeon are

found in most large tributaries of the Mississippi River south to the southem border of

Arkansas. Lake Champlain and its tributaries are the northeastem limit in the United

States. St. Roch des Auinaies is the eastern limit in the St. Lawrence River. The range

extends northeast to the Fort George River on the eastside of James Bay and northeast to

the Seal River on the westside of James Bay. The western limit extends into Alberta in

the Saskatchewan River near Edmonton.

Once abundant throughout North Arnerica lake snirgeon are currently threatened,

endangered or rare throughout the entire range. In the early 1800's sturgeon were

abundant in 23 States and 5 provinces (Scott and Crossman 1973). Overfishing is

certainly the major factor causing the decline of lake sturgeon but more recently loss of

habitat and pollution are considered additional factors in its decline. Lake sturgeon are

currently Iisted as Milnerable in Manitoba under the Manitoba endangered species act

(Ferguson and Duclcworth 1997).

Figure 1 - North Arnerican distribution of lake stwgeon. Hatched area outlines the greatest extent of the distribution.

In the United States the federai status is potentially endangered (Kempinger 1988)

and lake sturgeon have received protection in all 18 states to which it is native (Johnson

1 9 87). The problems faced by the lake sturgeon are also affiecting all species of shûgeon

worldwide. The Convention on International Trade in Endangered Species of Wild Fauna

and Flora (CITES: Appendix 1) has listed al1 26 species of sturgeon worldwide. Al1 8

species of sturgeon in North America are currently receiving legal protection (Johnson

1987).

History of the Lake Shirgeon FWhery

The early explorers and settlers in Manitoba described the waters as teaming with

sturgeon (Sunde 1959a). Early fisberman considered the lake sturgeon a nuisance fish

( D o w 1975) and prior to 1870 they were used as fertilizer or dried and burned as fire

wood (Williams and Vondett 1972, Pearce 1986). Eventually, due to its status in Europe

as a gourmet fish for caviar and smoked meat, it was recognized as a valuable fish. The

sturgeon was used for meat, eggs, oil, and the isinglass fiom the swim bladder was used

to clarifjr jellies and glues (Heacox 1952, Glover 196 1, Williams and Vondett 1962,

Downs 1975, Fogle 1975, Graham 1984, Lord 1984). Other species of sturgeon have been

used for similar uses. The Italians used the intestine to prepare a dish similar to tripe, the

Chinese used the gills in soup, and the bones have been used as tools by Indians (Glover

196 1). The lake sturgeon fisheries peaked in the late nineteenth and early huentieth

century. The overexploitation at these levels decimated lake sturgeon populations

throughout North America (Sunde 1959a).

Large scale fishing of lake durgeon started in the late 1800's and by 1895 the

total catch in Manitoba was just over 100,000 lb. (Gough 1991). The fishery expded

and peaked at 98 1,000 lb in 1900, in Manitoba (Sunde 1959% Lord 1984, Houston 1987,

Gough 199 1) and by 19 10 the fishery collapsed and the catch was reduced to 13,000 - 30,000 Ib.(Sunde 1959% Lord 1984, Houston 1987). The sturgeon fishery in Manitoba

has opened and closed many times. It was closed in 1910 (Sunde 1959% Houston 1987)

and reopened in 1916 to supplement war supplies (Sunde 1959a). As commercial catches

declined in southem Manitoba new regions such as the Nelson and Churchill Riven were

opened to a sturgeon fishery. History repeatted itself and the Nelson River sturgeon

fishery was closed fiom 1930-1937 and 19454953, the Churchill River was closed fkom

2926- 1938 and 1946- 1953 (Sunde 1959% Houston 1987). The Great Lakes region

showed a similar pattern. In 1880 the total catch was several million pounds and declined

to less than 100,000 by 19 17 (Sunde 1959% Lord 1984). The Lake of the Woods sturgeon

fishery declined 70% fiom 1893 to 1900 (Graham 1984).

Very few lake sturgeon fisheries still exist in Canada as of 200 1. In fact in the

pst decade al1 the small commercial lake sturgeon fisheries in western Canada were

closed. The major fisheries on the large Canadian lakes have been closed for many years

and it is very uniikely that sturgeon populations will ever retum to their historic highs.

Biology and Life History

Sturgeon are long lived fish that mature at an older age than any other fieshwater

fish species. Magnin (1966b) studied the development of the gonads and found that sex

could not be determined before age 9 and f ier age 9 the gonads developed slowly to

rnaturity. Female sturgeon mature anywhere fiom 17 to 33 years of age (Vladykov 1955,

Sunde 1959b, Williams and Vondett 1962, Magnlli 1966b, Cross 1967, Priegel and Wiah

1974, Downs 1975, Saunders 1981, Pearce 1986, Goyette et al 1988, Mecozzi 1988,

Guenette et al 1992). Males mature at 14 to 22 years of age (Magnïn 1966b, Priegel and

Wirth 1974, Saunders 1981, Graham 1984, Pearce 1986). After reaching sexual maîurity

females spawn every 3 to 7 years and males every 2 to 3 years (Vladykov 1955, Harkness

and Dymond 196 1, Magnin 1966% Downs 1975, Grabam 1984, Mecozzi 1988).

Spawning occurs in the spring The spring spawning migration has been well

docurnented (Harkness and Dymond 1961, Scott and Crossman 1973, Saunders 1981,

Larson 1988, Mecozzi 1988, Wallace 1991, McKinley et al 1998). Adult lake sturgeon

undergo a spawning migration in early spring nom overwintering areas in lakes and

rivers. They move upstream to areas of fast cunent or to the base of fdls (Harkness and

Dymond 196 1, Scott and Crossman 1973, Saunders 198 1, Larson 1988, Mecozzi 1988,

Wallace 1991). Spawning fish are thought to move to the spawning grounds only in the

year they are to spawn (Rusak and Mosindy 1997).

Temperature seems to be the main cue initiating the spawning sequence. Peak

spawning occurs at or about I O- 1 SOC (Harkness and Dymond 1 96 1, Scott and Crossman

1973, Kempinger 1988, Mecozzi 1988, LaHaye et al 1992). A small decrease in

temperature c m cause spawning to stop until optimal temperatures are reached again

(Graham 1984).

The spawning act takes place over cobble and boulder substrates in swift current

(Harkness and Dymond 1961, Graham 1984, Kempinger 1988). Males and females are

oriented facing upstream into the cumnt (Ono et al 1983). Several males are grouped

with an individual female, vibrations of the male dong the female cause release of the

eggs and sperm (Harkness and Dymond 1961, Scott and Crossman 1973, Graham 1984,

Kempinger 1988, Mecozzi 1988). Sturgeon are capable of producing large numbers of

eggs due to their large size. Female sturgeon produce 4000 to 7000 eggs per pound of

body weight (Fogle 1975, Pearce 1986) and large females are estimated to shed more

than one million eggs (Phillips et al 1982, Eddy and Underhill 1976). Currier (1949)

estimated the number of eggs produced by female sturgeon to range between 100,000 and

885,OO eggs and a 200 pound female producing up to 3 million eggs. Sturgeon eggs have

up to 13 micropyles that make it easier for sperm to penetrate the egg. Sturgeon spenn

relative to most other fish species is relatively long-lived (Dick, unpublished).

The eggs are adhesive and fall to the substrate to which they adhere and where

they remain through embryonic development until hatch (Harkness and Dymond 1961,

Williams and Vondett 1962, Fogle 1975, Eddy and Underhill 1976, Saunders 1981, Ono

et al 1983, Graham 1984, Pearce 1986, Kemginger 1988, Mecozzi 1988, Wallace 199 1).

Eggs develop in 5-8 days depending on temperature during which time they are nouished

by a yolk sac (Harkness and Dymond 196 1, Williams and Vondett 1962, Scott and

Crossman 1973, Ono et al 1983, Graham 19û4, Pearce 1986, Mecozzi 1988). The young

fiy start to drift downstream and begin active feeding around two weeks after hatch

(Scott and Crossman 1973, Kempinger 1988, Mecozzi 1988, LaHaye et al 1992).

Small lake sturgeon, following the resorption of the yolk, until they reach about

20 cm feed on rhizopods, algae, infusoria, microscopic crustacea, baetidae, diptera,

chironomidae, simuiiidae, and polymitarcidae larvae (Van Oosten 1956, Williams and

Vondett 1962, Eddy and Underhill 1976, Saunders 1981, Kempinger 1988, Choudhury et

al 1996, Kempinger 19%). Feeding changes as the fish grow but invertebrates are the

main food source throughout the entire life cycle (Table 1).

Lake sturgeon iniiahit large lakes and rivers (Harkness and Dymond 1961,

Houston 1987). They are thought to be bottom-dweliing fish in large, shallow, highly

productive shod areas (Harkness and Dymond 1% 1, Crossman 1976, Saunders 198 1,

Graham 1984, Houston 1987). Young lake sturgeon spend their fïrst year in the river

where they hatch, thm move to the lake and inhabit the same areas as larger lake

sturgeon (Graham 1984). Kempinger (1996) captured the majority of age O lake sturgeon

in areas ofdetectable current, ou flat substrate composeci of coarse sand anci grave1 with

no rooted vegetation Divers observed the juvenile lake sturgeon orienting into the

current remaining in contact with the substrate. They appeared to be feeding on benthic

invertebrates drif ig with the currents. Chiasson et al (1997) observed increased

densities of lake sturgeon in areas of saud and clay substrate which also produced the

highest densities of invertebrates.

Table 1 : Lake sturgeon food habit &ta fkom the fiterature.

Location I Food

Lake Wimiabago Summsr-DepCnia, Chirociomids, sfmam Tyhcwa, Winar- Choudhuyetal1996

Miesota AlberCri

Lake Waswanpi,

Waswanipi River

Lake Nipgsing -, vagabtion, -eh (1-27. m w l b , sniib, ~ b m Love 1972

Kenogami River aynsh, caddwk, ~ g o n f i i e s , dsmt OMNR 1Sô6

Lake Nipigon rnaylk , cadâdb, chiioriomio, dam, & ~ g o M h , ïnmter beslk5, C k m m et ai 1923

rniJI, d.rm, aylM. Unmiibre-

d i m r , a i i i l r , i r a a ~ , ~ , ~

T-,-,DObara

Pk-@=,~odsnsta

Canada

Ontario

nvmphr, smaM M. kschsr, amhboth, -, planb 1 Missouri beches, Snaik* dams, n#alanme

Pnpre ta i 19û2

PiekandNel#wi 1970

M.ginandHupsr 1970

Miinetrota cbmS. anab. mynih, a-, ii#dp, v- EddyandUndcrtlW 1976

Quetico. Ontario Crossman 1976

kechss, rnriilr, cbm, hvembmm m n i r i h ~ a I S - j W d b b 7 ~

Houbari 1907

Msc((ay 1963

Generai

Black Lake, MI

General Great Lakes

woms, imectbivse (-), m m , cwbceam Hem-, kachss, chiiorunnidr. Orcanechml nematdes

aqmtic hacb, amtaan, dsad îkh

c ~ t a c e i n i , i i l s d I I C V M , ~ , n i h ~

Vklykov 1955

Hay-Chmidswdri 15ô7

P e n 1-

Onoetal19û3

Movements and Habitat Sektion

Lake Sturgeon

Since much of the information on lake sturgeon movement is anecdotal with few

detailed studies this section includes information fiom lake sturgeon and other sturgeon

species. The movements of individual lake sturgeon are extrernely varied. Movements of

100 lm and greater have been obsemed (Sandilands 1987, Swanson et al 1988).

The majority of fish have a more sedentary behavior moving within ranges under 20

kilometers (Haugen 1969, Nowak and Jessop 1987, Sandilands 1987, Swanson et al

L990, McïIomell 1992, Fortin et al 1993). Factors influencing rnovements are spawning,

temperature, water current, depth, and substrate. Furthemore, lake sturgeon movements

and habitat selection are not well understood outside of the spawning migrations.

After the spawning migration lake sturgeon are thought to r e m to a 'home ara'

(Scott and Crossman 1973, Thueznier 1985, Threader and Brousseau 1986). McKiniey et

al (1998) reported lake sturgeon moved to feeding areas during p s t spawn dispersal

followed by a late summer migration to areas where they spent the winter.

Movement is positively correlated with water temperature (Hay-Chmielewski

1987, Swanson et al 1988, Rusak and Mosindy 1997). Temperatures near or above 20°c

however cm cause a decrease in movement (McKinley et al 1998). Temperatures above

2 0 ' ~ seem to be near the upper lethal limit. Lake sturgeon are generally not found in

waters with temperatures higher than 2 3 ' ~ (Ono et al 1983). The winter sport fishery in

Lake Winnebago indicates that sturgeon are active in the winter (Harkness and Dymond

196 1).

Lake sturgeon are thought to be shallow water fish (Ehrkness and Dymond 1961,

Crossman 1976, Saunders 1981, Graham 1984, Houston 1987). Rusak and Mosindy

(1997) found lake sturgeon preferred water depths of 6m or greater and Hay-

Chmielewski (1987) fond prefemd depths to be 6 to 13m.

Current is known to be important during the s p ~ g spawning migration and the

spawning sequence but it may also be important outside of this period. R d and

Mosindy (1997) found the movements within Lake of the Woods year round were related

to areas of higher flow such as channels, peninsulas, and river mouths.

Other sturgeon species

Information on other sturgeon species indicates that they prefer sites with some

current and they undergo a spawning migration. Shovelnose sturgeoa, Scaphirhynchus

platoyzchur, in the Mississippi River, are fiequently located in or near a scour hole just

outside and downstream of wing dams and closing dams (Hurley et al 1987, Curtis et ai

1997). Shortnose sturgeon, Acipemer brevirostnnn, in the Connecticut and Merrixnack

River aggregated above reaches where river flow was slowed by tides, river morphology

or impoundments (Kieffer and Kynard 1993).

Shortnose sturgeon show a similar pattern to lake shirgeon in their mual

movement patterns. The spring spawning migration is followed by downstream

movement to potential feeding areas and late summer movements to overwinterhg

habitats (Buckley and Kynard 1985, Hall et al 1991, Kieffer and Kynard 1993, O'hemon

et al 1993)-

Al1 shirgeon species undergo a spawning migration upstream to suitable spawning

habitat in strong current with pebble and cobble substrate. Acipnser baeri (Votinov and

Kas'yanov 1978), Acipmer sinenris (Wei et al 1997), H'so hwo, Acipenser siellatus,

and Acipenser guldemtaedti (Pavlov and Vilenkin 1989, Veschev 1991), Acipenser

brevirostnnn (Buckley and Kynard 1985, Hall et al 1991, O'herron et al 1993, Kieffer

and Kynard 1993, Moser and Ross 1995), Acipenser scaphirhyncus (Hurley et al 1987,

Curtis et al 1997) and Acipenser trammonfanus (Parsley and Bechan 1994) migrate

upstream to spawn.

Growth

Fish growth is highly indeterminate and very plastic (Weatherly and Gill 1987).

Growth parameters are determined by a complex combination of external and intemal

factors (sakanov et al 1987). Sex, temperature, limnology, f& population density, and

the abundance of other species (cornpetitors and predators) can al1 affect the growth of a

fish (Carlander 1997). Bakanov et al (1 987) tested several factors and concluded that

temperature has the strongest affect on fish growth. Variations in seasonal growth and

changes in growth of a species at different latitudes are expected due to the relatiomhip

between these factors and temperature.

The growth of lake sturgeon has been reported for many populations (Table 2). A

cornparison of age-iength data shows that these variables Vary between populations

(Figure 2). Differences in latitude are thought to be the prixnary factor influencing

changes in growth (Harkness and Dyrnond 196 1, Houston 1987, Sandilands 1987,

Mecozzi 1988, Bearnish et al 1996).

Table 2: Studies and locations of lake sturgeon growth.

Locaüon Lake Winnebago

Poygan, Winneanna, Butte dus Mortt U ~ m r NOrVt Fork Fiamûeau River

Moose River, Onfario 1 Thmadsr end Brousseau 1986 Moose River. Ontario ûeambh et al 1996

Author@) Kempinger 1988,1996 P-I and Wrth 1978

Sctid11986 , . . - - -

Winnebago, Butte de Morts, Poygan, Winnacorinet Wisconsin

Lake Wisconsin Black Lake, M i n Btack Lake, Michigan Black Lake, MiiQan

Michigan Lake Nipissing, Ontario

Frederick House, Abitibi, Mattagarni Rivsrs Groundhog and Mattagarni Riven, Ontario

Moose River. Ontario

- -

Probst and Cooper 1955 MaCo- 1988

Lanon W88 Shouder 1975 Baker 1980

Hay-Chmieiewski 1987 Williams and Vondett 1962

Love 1972 Payne 1987

Nowak and Jessop 1987 Thrspder 1981

Laie of the Woods 1 Mosïndy 1987 I

Upper St Lawrence Johnson et al 1098

Chipman Lake, Ontario Kenogami River, Ontario Kenwami River. Ontario

Goddard 1963 OMNR 1988

Sandilinds 1987

Ottawa River, Quebsc St. Louis, St- Pierre, ûew Montmges, Quebec Lake St. Francis. St. Lawrence River. Quebec

Roussow 1957 Fortin et al 1993

Currisr and Roussow 1951 . - - - - -

Flueve St. Laurent, Quebec Flueve St. Laurent. Quebac

Dumont et al 1987 Magnin and Beaulisu 196û

Flueve St Laurent, Quebec Flueve St. Laurent, Quetmc La Grande Riviera Quebec

Goyette et al 1988 Magnin 1964 Maanin 1977 . -

Des Prairie, L'Assomption Rivets, Quebec Nelson River

- 1

LaHaye et al 1992 Sunde 1 959a. 1959b

Nelson River Nelson and Churchill Riven Si~iwesk Lake. Nelson River

Kihmbi 1- Kooyman 1955 Patalas 1988

Sipiwesk Lake, Nelson River Lowsr Saskatchew~n River

Sopuck 1987 Wallace 1991

Saskatchewan River 1 Royer et al 1968 South Saskatchewan River, Alberta

Canada North Amefica North America North America North Amefïca

Hiugen 1969 Houston 1987

Fortin et al 1- Harkness and Dymond 1961

Harlviess 1923 Lanon 1988 d

Figure 2. Cornparison of lake sturgeon age-length data (Appendix 2) reported in the literature.

o Sipiwesk Lake(a) w Sipiwesk Lake(b) 4 Saskatchewan River, SU o Saskatchewan River, AB - Moose River A Mattagarni River + Kenogami River

La Grande River 0 Lake St. Francis 4 Lac des Deux Montangues A Lac St-Louis

Lac St-Pierre x Michigan A Menominee River

Lake Winnebago(a) m Lake Winnebago(b) - Flambeau River

Hydroelectric Development and stuqpn

The responses of a river or river ecosystem to impoundment are complex as they

depend on sediment, geomorphic constraints, climate, dam structure and operation

(Power et al 1996). The installation of hydroelectric dams irnpedes the movement of

migrahg fish up and dowmtream as well as altering water clarity, flow, water

temperature, substrate, and food availability (Yelizarov 1968, Spence and Hynes 1971%

Spence and Hynes 197 lb, Khoroshko 1972, Pavlov and Slivka 1972, Zakharyan 1972,

Lehmkul1972, Geen 1974, Clay 1975, Mackay 1979, Baxter and Glaude 1980, Armitage

1984, Ward et al 1986, Boon 1988, Lauer 1988, Veschev 1991, Stevens et al 1997, Pardo

et al 1998). Spawning migrations and sites are altered, and the food chah is disrupted as

the habitat parameters are altered and cornpetition is changed Growth and demities of

fish populations can change as the food supply changes or cornpetition between species is

altered.

Sturgeon worldwide have been af%ected by the development of dams. The

negative affects of hydroelectric development on the Volga River have been studied

extensively (Yelizarov 1968, Pavlov 1971, Khoroshko 1972, Pavlov and Slivka 1972,

Artyukhui et al 1979, Pavlov and ViIenkin 1989, Veschev 1991). The Volgograd dam is

the fist dam encountered as sturgeon move upstream fkom the Caspian Sea (Yelinuov

196 8) and it restricts the spawning migrations of Huso h m , Acipenser guldenstaedtli,

and Acipenser stellatus (Pavlov 1971, Pavlov and Vileokin 1989, Veschev 1991).

Acipenser baeri in the Ob River lost several spawning sights due to the Kamenogorsk and

Novosibirsk hydro stations (Votinov and Kas'yamv 1978). Wei et al (1997) studied the

effects of the Gezhouôa dam on the Amur and Yangtze Rivers. Acipemer gladiw

spawned over 800 km of the river at 16 natural sights but is now limiteci to one sight

below the dam. The Yenisey River has also been modified by hydroelectric development

and the southern range of sturgeon in this area has been reduced by 500600 km (Ruban

1997). Acgenser sturio no longer occurs in the River Tagus, Portugal (Assis 1990). Four

other species of anadromous fish in the system no longer reach the Spanish section of the

River Tagus. The total catch of Acipenser nudiventris in the Kura River bas steadily

declined since river regdation (Markarova et al 1 99 1).

In North America the shortnose, Acipenser brevirostnm, Atlantic, Acipemer

oxyrhyzchus, and white shirgeons, Acipemer hohnnontmnr, are affccted by

hydroelecû-ic dams (Parsley and Beckman 1994, Beamesderfer et al 1995, Moser and

Ross 1995). The spawniag migration of shortnose sturgeon on the Lower Cape Fear

River, North Carolina is disrupted by dams as well as incidentai catches by commercial

fishïng (Moser and Ross 1995). Spawning may be completely stopped by the

combination of these two stressors,

The effects of hydroelectric development on lake sturgeon populations have been

studied on the Saskatchewan River (Wallace 1991). Moose River (Payne 1987,

Brousseau and Goodchild 19891, Mattagami River (McKinley et al 1993, McKinley et al

1998), Meaorninee River (Thuemler 1997), Nelson River (Swanson et al 1990), and the

Sturgeon River (Auer 1996). Generally, hydroelectnc development has a negative effect

on sturgeon populations. Pavlov and Vilenklli (1989) described hydroelectric dams as a

valve that permits downstream migration only. This reduces the potential for lake

sturgeon populations in the upper reaches of a system as there will be a net migration

downstream over t he . In some cases fish migration through dams is almost ni1 therefore

each section of river between the dams should be wnsidered a distinct population and

managed separately (Thueder 1997). The design, location, and operation of

hydroelectric dams should consider these factors if lake sturgeon populations are to be

maintained or improved. Minimum flow requirements for lake sturgeon need to be

established (Brousseau and Goodchild 1989). The natural cycles of high spring flows and

lower flows through summer and winter should be maintained.

Undoubtedly manmade barriers across streams affect lake sturgeon movements.

However there are numerous natural barriers to Lake sturgeon movements in most of the

large river systerns in North Amenca As a consequence there were, at the peak of lake

sturgeon populations, naturally fragmentai populations. The problem today is a lack of

good historical ecological data to determine which components of lake sturgeon

populations had good mixiog of genotypes and wtiich components have been isolated for

some time. Very Wely the now almost extinct large lake populations were the major

regions for maintahhg substantial genetic variation.

ACOUSTIC TELEMETRY

The history of biotelemetry dates back to the development of the transistor in the

late 1950's (Kenward 1987). It has been applied to birds, marnmals, reptiles, fish, and

even insects, and to date over 500 species of anhals have been studied using

biotelemetry (Kalpers et al 1988). It has also been used to monitor dobsonfly larva

activity (Hayashi and Nakane 1989) and for satellite tracking gray seals (McConnell et al

1992).

Goals of telemetry include howledge of habitat preference based on fimi,

temperature, or in relation to groups such as male/female old/young classincations

(Aebischer et al 1993). Defining an animals home range (Todd and Rabeni 1989) is ofien

a goal of a telemetry study. More specificallyy telemetry c a . tell us about migration

routes, dispersai, sight fidelity, animai association. habitat utilimtion, and preference

(White and Ganott 1990).

Telernew has been used to study a wîde range of fish species including bass,

Microptem sp., (Bain and Boltz 1992, Todd and Rabeni 1989, Bruno et al 199û),

squawfish, Ptychocheilur oregonensis, (McAda aml Kaedig 199 1). muskeilunge, Esox

maquinongv, (Hanson and Margenau 1992), and catnsh, I c t a l ~ s punctatus,

(Summerfelt and Mosier 1984, Marty and Summerfelt 1986) as well as countless others.

Telemetry has been applied to lake sturgeon by Basset (1982), Leclerc (1984), Swanson

and Kansas (1987), Hay-Chmielewski (1987), Swanson et al (1988), Thuemier (1988),

Swanson et al (1990), McKinley et al (1991), Mosindy and Rusak (19911, MacDonell(1992),

Rusak and Mosindy (1997), and McKinley et al (1998).

Early telemetry studies on fish involved horizontal movements, only with the

development of pressure sensing transmitters, horizontal and vertical movements could

be assessed (Luke et al 1973). This is very important in systems where temperature,

salinity, oxygen or other factors Vary with depth (Luke et al 1973). Biotelemetry studies

involve assessing horizontal and vertical movements, abiotic factors such as temperature,

salinity, oxygen and physiological factors such as biopotentials (ECB, EEG, EMG), body

temperature, respiratoiy rates, blood pressure, heart sounds, intestinal pressure or PH

(Adams 1965).

The underlying assumption in aLl biotelemetry studies is that the presence of the

trammitter, its radiated signal, and the receiving system do not affect the animals normal

behaviour (Stasko and Pincock 1977). Biotelemetry is a n excellent twl to monitor

certain behaviors in the field but it is essential that the method does not interfere with

natural behavior. Factors to be considered when undertaking a telemetry study are the

effects of fish handling on the animals behaviaur, the tag weight and size on fish

swimming ability and potential pathology produced by the tag.

AU animals show a reaction to handling (McKay 1971). Short and long term

affects should be anticipated. M e r an animal is released the immediate behavior will

likely be atypical and this behaviour may last for several hours or several days. Atypical

behavior rnay include cessation of feeding and extremely active or extremely docile

behaviour. Another problem to consider is when and where to release the animals. Fish

are ofien put into holding tanks &er king tagged to dlow the fish to recuperate before

they are released. Pike and muskellunge showed better survival when released into the

open water rather than into a codïned area (Ross 1982). The continued holding of

stressed fish may not be the best solution. The best method will depend on the fish king

studied-

Extemal tags cm affect balance, buoyancy, drag, and they may become entangled

in vegetation (Marty and Summerfelt 1986). The weight of the îransmitter should be as

small as possible to have the least affect on buoyancy and swimming. A general guideline

for trammitter weight is about one to two percent of the total weight of the fish (Hocutt

1989, Winter et al 1978). Buoyancy and swimming performance have been studied

extensively in rainbow trout and several salmon species (Mellas and Haynes 1985, Fried

et al 1976, Moore et al 1990, Roberts et al 1973a, Lucas 1989). No efféct was found on

buoyancy and swimming in some studies (Lucas 1989, Roberts et al 1973% Moore et al

1990) but others report that it has sigainuint effects on fish behaviour. Blaylock (1 990)

found that the size of the host was important. In aquaria prior to release, age O cownose

rays swam much slower than the corresponding controls whereas age 1 rays showed no

difference in swimming performance. Similar results were seen in Atlantic salmon pan

(Greenstreet and Morgan 1989). The srnailest size group (460mm) were unable to

maintain proper speeds and unable to maintain buoyancy in the water columm Generally,

Atlantic salmon smolts are unaffected by tagging (McCleave and Stred 1975, F M et al

1976, Moore et al 1990).

Stress may increase when a fish is carrying a tag. Rainbow trout showed increased

tail beat fiequency and opercular beat rate when visually monitored in the lab (Lewis and

Muntz 1984). Tags may cause the fish to use up more energy to accomplish nomal daily

activities. Tagged rainbow trout became exhausted much quicker when attempting to

maintain position in a strong current (MeIlas and Haynes 1985). Another problem is the

wound that an e x t e d tag creates. White perch when tagged showed extreme muscle

damage as the holes enlarged due to movement of the atîachment wires (Mellas and

Haynes 1985). Fungal infections are also a problem when creating extemal wounds

(Mellas and Hayws 1985; Roberts et al 1973% 1973b). The microbial agents have easier

access to the muscle (Roberts et al 1973a), which is nonnally protected by the scales and

a layer of mucous. The application of disinfectants after tagging cm reduce fiingai

infections but if the wounds don't heal quickly h g u s may becorne a serious problem.

Rainbow trout were seen scraping the bottom of the tank when tagged ('ellas and

Haynes 1985).

Finally, the receiving system is the 1 s t source of animal interference to be

considered. Tracking animals in a boat or by plane may cause the subject to act

abnonnaily. A subject may avoid the observer or may be curious or aggressive and move

towards an observer. Pink, Onchorhynchus gorbuscha, sockeye, Onchorhynchzlr nerku,

and AtIantic salmon, Sdmo salar, as well as white bas, Morone chrysops, showed no

avoidmce response to repeated passes by a boat (Stasko unpublished nom Stasko and

Pincock 1977). The dus& shark showed a diving response to boat movements (Carey and

Lawson 1973).

FEEDING ECOLOGY AND COMMUNITY STRUCTURE

Fish feeding ecology is driven by abiotic (Wetzel 1983) and biotic factors (Sih et

al 1985, Kerfoot and Sih 1987). The food web is generally comprised of a series of

trophic levels (Gerking 1994). Generally, four trophic levels are recogmgnized; primary

producers, primary consumers, secondary consumen and tertiary consumen. Organisms

that feed on sirnilar foods make up each trophic level (Gerking 1994). In some cases

species may feed at two trophic levels and larvd fish often feed at a different trophic

level than adult fish. When classifjing trophic statu to a species of fish all these fêctoa

must be included.

Root (1 967) used the term 'guild' to describe a group of animals that exploit the

same class of environmental resources in a similar way. The term guild has been used to

group species based on habitat, breediLlg, and feeding strategies as well as other factors.

The guild categorization is a slightly smaller grouping than that of the trophic level

categonzation.

In an aquatic environment the primary producers are phytoplanlton, benthic

algae, and macrophytes (Gerking 1994). Detritus is also considered part of the first

trophic level. Detritus is nonliving organic matter in various States of decomposition

(Gerking 1994, Darne11 196 1). Many large consumers have some portion of detritus (5%)

in their diet @amel1 196 l), however, few fish use detritus as a principal food source.

Planlcton is a food source for most fish at some stage in their Life (Lazzaro 1987).

The larval stage of most marine and fieshwater fish feed on zooplankton (Gerking 1994).

As the fish grows, they may switch to a larget prey (Lazzaro 1987).

Predation is an extremely important factor when attempting to undentand

cornmunity structure and the relationships between various organisms (Curio 1976).

Piscivores are at the top of the food chain and are geaerally found in low nurnbers in

most systems.

Feeduig guilds are any group of species that feed on a common group or type of

prey species. A guild should not be created by assuming bctional relationships

(Hairston 198 1). Angemeier and Kan (1983) grouped fish into guilds of algivore,

aquatic insectivore, and geceral insectivore which were composed of species overlapping

in food use by 90% or greater. Roots definition, however, does not require cornpetition as

a factor in detetmining guild structure.

Guilds are advantageous allowing cornparisons between systems containing the

same guild, even if species composition is different (Root 1967). The benthic

invertebrate guild is one of the most speciose guilds of fish in North American warm-

water streams (Greenberg 199 1). A group such as this could be a starting point for

cornparhg two streams in different geographical locations. The aquaîk community may

contain different species but if the species names are replaced by the guiid names the

community may look quite similar.

GROWTH AND FEEDING OF OTHER FISHES LN BOREAL SYSTEMS

Lake sturgeon are known benthivores but more recent stuàies indicate there may

be a pelagic componeot to their diet (Choudhury et al 1996), many other species feed on

similar food items. If lake shirgeon enbancement studies are to continue we need to know

much more about f d items comumed; ie what, how much and by what species of fisb

The major fish species, by biomass, on the eastside of Lake Winnipeg, are perch, sauger,

wdleye, pike, suckers, and mooneye.

Perch, Waiieye, and Sauger

The range of yellow perch, walleye, and sauger overlap in Alberta, Saskatchewan,

Manitoba and Ontario (Scott and Crossman 1973). Walleye, yeilow perch, pike and white

sucker form the vital subcomponent of Precambrïan Shield north temperate fish

communities (Ryder and Kerr 1978). The interactions of walleye, perch, and sauger have

been studied by Clady (1978) and Ryder and Kerr (1978). Yellow perch and walleye

populations appear to be the most compatible and thrive in the same enWonments

(Clady 1978). Community structure is more diverse in lakes where saugers are well

established and less diverse when yellow perch are abundant (Clady 1978).

Yellow perch have a widely varying growth rate under various conditions (Keast

1977). The first year of growth can vary by an order of magnitude (Post and McQueen

1994). Growth is affecteci by sex (femaie~males), temperature, limnology, food,

density, and abundance of other species (Carlander 1997). Density dependent changes in

growth have been observed in Lake Champlain (Cobb and Watzin 1998) as weU as Lake

Wimebago (Staggs and Otis 1996). Age-O perch growth seems to be primarily affected

by the abundance of zooplankton, generally Daphnia spp. (Noble 1975, Mills et al 1989)

and benthic prey (Nakashima and Leggett 1975, Post and McQueen 1994). Figure 3a

shows a few growth curves fiom areas comparable to Round Lake.

The diet of yellow perch is quite variable. Perch are generalist feeders. Diet will

change as the fish gmws as well as with prey availability. Diet generally shifts nom

zooplankton to macrobenthos to fish as perch grow (Clady 1974, Nakashima and Leggett

1975, Keast 1977, Hartmann and Numam 1977, Paxton and Stevenson 1978).

Clady and Hutchinson (1976) fouad changes in consumption of perch in Oneida

Lake were similar to the changes in the bottom fauna. Cornpetition can also affect

feeding behavior. Removal of white suckers caused changes in the diet of yellow perch in

Douglas lake, Michigan (Hayes et al 1992), and Wilson Lake, Minnesota (Johnson 1977).

Walleye and sauger growth is aiso aEected by sex, limnology, temperature, f a

density, and cornpetition (Carlander 1997). Selected growth curves for sauger and

walleye are show in figures 3b and 3c respectively.

Sauger and walleye diet shifts from zwplankton to chironomids, Boetis, and

Heurgenia, to fish (Carlander 1997).

Figure 3. A) Growth of yellow perch in Lake Winnipeg (Bajkov 1930), Lake of the Woods (Carlander 1950), and Weber Lake, WI (Schneberger 1935)

B) Growth of sauger in Minnesota (Van Oosten 1 W8), Lake of the Woods (Carlander 1950), and Manitoba (Bajkov 1930)

C) Growth of walleye in Lake Manitoba (Bajkov 1930), Marie Lake, AB (Craig and Smiley 1986), and a mean for Canada (Carlander 1997)

&Lake W m L 8 k e of the W d

C) wallaye growth IMarie Lake. Aiberta

Sauger, in Lewis and Clark Lake, South Dakota, absorbed the yok sac in 7-9 days at

which time they started to feed primdy on Cyclops (Nelson 1968). They shift to larger

zooplankton as they grow, Daphnia and Diaptomus, eventually switching to fish when

they reached 70-1 10 mm (Nelson 1968). Walleye in Ohio reservoirs fed on zooplaokton

to age 2 then switched to a diet of fish and crayfish (Paxton and Stevenson 1978). Nomk

reservoir waileye and sauger were highly piscivorous as adults feeding almost entirely on

gizzard shad and black crappies (Fitz and Holbrook 1978). Walleye in Oneida Lake fed

primarily on yellow perch (Fomey 1980). Sauger in Lake of the Woods ate fewer

invertebrates than walleye (Swenson 1977).

The interactions of these three species are complex even when the affects of other

species aren't considered. Biotic interactions between these species can lead to bottom

up and top down influences on the food web. Abundant walleye populations can limit

perch recniitment leading to high perch growth rates and low walleye growth rates

(Rudstam et al 1996). The opposite can hold true as high perch densities would lead to

low growth rates for perch and bigh growth rates for walieye.

Cornpetition between wdleye and sauger can affect growth as systems containing

high prey density leads to high growth rates for both sauger and walleye (Staggs and Otis

1996).

Pike

Pike are generally the top predator in most systems. Pike are highly piscivorous

(Seaburg and Moyle 1964, Lawler 1965, Wolfert and Miller 1978). Invertebrates,

however, are part of the diet for large pike in some systems (Wolfert and Miller 1978).

Crayfish, magies, dragonflies, caddisflies and leeches were found in duit pike

stomachs in Herning Lake, Manitoba (Lawler 1965). The interactions of pike with other

species are generally thought to fit into predator-prey categories with pike king the

predator and most other species, the prey. Large pike fit this categocimtion well.

However, when pike are looked at fiom the early stages of development a different story

seems to appear. Pike start to feed at 11-12 mm in length (Hunt and Carbine 1950).

Cladocera are the main food source until they reach 30 mm (Hunt and Carbine 1950,

Frost 1954). Over 30 mm to about 100 mm they start to feed on aquatic insects and fish

until the diet shih almost entirely to fish (Hunt and Carbine 1950, Frost 1954, Bregazzi

and Kennedy 1980).

Cornpetition for cladocera and aquatic insects betweea pike, sauger, walleye,

perch and other fish will occur if the resources are limiting. There was evidence of pike

in Petersons Ditches, Houghton Lake, Michigan, cornpeting with other species of fish for

the availabie invertebrates (Hunt and Carbine 1950).

Mooneye

Growth of mooneye is shown in Figure 4a (Van Oosten 196 1, Glenn 1975b).

Mmneye in the Assini'boine River fed entirely on insects with corixid beetles occurring

in 80% of the fish captured (Glenn 1975a). Mooneye showed no change in diet with age

(Glenn L975a). Young of the year mooneye in the Assiniboine River ate maMies,

caddisflies, and chironomids until mid July when they were large enough to eat addt

C O ~ X ~ ~ S (Glenn 1978). Stonef'es were the predominaot food in fall and winter of the

first year (Glenn 1978).

Suckers (white and shorthead redhorse)

White sucker and shorthead redhorse growth is show in Figure 4b (Chambers

1963) and 4c (Scott and Crossman 1973) respectively.

White suckers in Wilson Lake, Minnesota, fed primarily on chironomids and

Hexagenia (Johnson 1977), and chironomids, Simulium, and Hydropsyche in the South

Platte and St. Vrain Rivets, Colorado (Eder and Carlson 1977). Competition between the

white sucker and perch has been experimentally studied in Douglas and Littie Bear

Lakes, Michigan (Hayes et al 1992), and between white suckers, perch and walleye in

Wilson Lake, Minnesota (Johnson 1977). Perch shifted their diet h m zooplankton to

zoobenthos with the removal of white suckers fiom Douglas and Littie Bear Lakes

(Hayes et al 1992). Perch growth and abundance increased after the removal of white

suckers from Wilson Lake (Johnson 1977). Walleye also showed slight increases but the

effects were not as pronounced as they were for perch-

Figure 4. A) Growth of mooneye in Lake Erie (Van Oosten 1961) and the Assinihine River (Glenn 1975a)

B) Growth of the white sucker in Lake of the Woods (Chambers 1963) C) Growth of the shorthead redhorse in the Saskatchewan River

(Scott and Crossman 1973)

1 6 Lake Erie. ON [ . Assiniboine River, MB

Age (years)

6) white urcker granRh [*Lake of ~he woodr 1

70

1 O Saskatchewan River

CHAPTER 1. Biological statistics of lake sturgeon in Round Lake, a pristine system,

and two mature resemirs on the Winnipeg River.

INrRODUCTION

It is generally believed that sturgeon populations are fkagmented and genetically

isolated following irnpoundment of certain parts of the river. Furthemore it is also

accepted that dams restrict sturgeon movements. However, most studies using radio tags

dealt with large sturgeon, some of which are reported to move great distances. There is

very little information on the general distribution of lake sturgeon of al1 sizes fiom an

aquatic system where there are no impediments to movement. Similarly there is very

little information about the distribution of lake sturgeon in impounded systems. The

Winnipeg River is an interesthg system to study lake shirgeon distribution as it has a

number of mature reservoirs in which water levels have k e n raised but other parts of the

river which are essentially unperturbed habitats or in other words it is a flowing river.

There are three aspects of ùnpoundment; 1) the initial flooding caused by a new

impoundrnent releases a large amount of nutrients into the system fiom newly flooded

land area leading to an increase in primary productivity (Ellis 1936, Baxter and Glaude

1980, Bernacsek 1984, Gibberson et aI 1991). 2) the restriction of movement by

migratory fish, which is particularly important to lake sturgeon which migrate extensive

distances to spawn. 3) loss of sp~iwning and nursery habitat.

The changes to the environment due to hydroelectric dams are thought to be

detrimental to the reproductive success and the general life history of lake sturgeon

(Harkness and Dymond 1961, Priegel 1973, Scott and Crossman 1973, Ono et al 1983,

Pearce 1986, Lauer 1988, Brousseau and Goodchild 1989). Very few studies have been

designed to look specifically at the effects of dams on lake sturgeon populations or

reproduction. McKinley et al (1993) studied the amount of plasma nonesterifid fatty

acids, as a measure of nutritional stahis, in lake sturgeon above and below four dams on

the Mattagami River. The results determined that fatty acid Levels were different above

and below the dams. This indicates a potentiai difference in nutritional status pssibly

due to availability of food. Auer (1996) stuclied the spawning of lake sturgeon in the

Shirgeon River, Michigan, in years of nin of the river flow and years of peak operation of

the Prickett Dam. Differences were noted in t h e at the spawning site, number of

individuals number of fernales, number of larger fish and number of ripe-running fish.

Many of these factors are not independent and most may be related to the spawning

periodicity of lake sturgeon and not directly related to dam operation since the study only

took place over a five year period. Female sturgeon spawn every three to five yean so

changes in abundance andlor size etc. may be due to this factor. Several studies have

looked at the movement of lake sturgeon in relation to hydroelectnc dams (McKinley et

al 199 1, Swanson et al 1990, McKinley et al 1998). McKinley et al (1998) reported that

lake sturgeon are prone to impingement or entrainment due to their migratory behaviour

but the altered river flows appear to enhance reproductive development. McKinley et al

(1 99 1) found littie movement in the vicinity of the control structures. Movements of lake

sturgeon upstream through dams are rare, or impossible if no fish ladder is present, and

movement downstream over dams does occur but is uncommon. Dams hgment lake

sturgeon populations by reducùig movements to certain areas and stopping spawning

migrations. Lake sturgeon in Black Lake, Michigan, have been separated fiom Lake

Huron and limited to an 1 1 km upstream migration by dams above and below the ldce

(Hay-Chmielewski 1987). The dam at the outlet of Rainy Lake has caused the loss of

spawning sites upstream (Mosindy 1987).

Lake sturgeon may spawn below dams in the strong flows produced by the release

of water. Lake sturgeon spawning has been observed below the Prickett Dam on the

Sturgeon River (Auer 1996). Naturally reproducing populations are said to exist on the

north fork of the Flambeau River (Scholl 1986), and the Menominee River (Thuemler

1985), both of which are affecteci by impoundment-

Sturgeon are often thought to be slow growing fish but they generally grow about

one pound per year which few other fkeshwater fish can attah (Kooyrnan 1955). Uany

studies have looked at sturgeon growth covering most of its geographic range. Several

patterns have emerged fiom these studies. Sturgeon growth varies throughout its M e

history. Growth rate in length is rapid at younger ages then declines at which time growth

rate in weight increases (Harkness 1923, Currier and Roussow 195 1, Probst and Cooper

1955, Harkness and Dymond 196 1, Threader 198 1, Threader and Brousseau 1986,

Nowak and Jessop 1987, Sandilands 1987, Mecozzi 1988, Ontario MNR 1988). Variation

in growth between systems is also seen. The major trend in growth rate seems to be

directly related to temperature or Iatitudinal clifferences in distribution as well as food

availability (Harkness and Dymond 196 1, Houston 1987, Sandilands 1987, Mecozzi

1988, Beamish et al 1996). Fortin et al (1996) included longitudinal differences in

distribution and differences in water chemistry to also be important factors affecthg

growth.

Population estimates have been reported from the Menominee River (Priegel

1973, Thuemler 1985, Thueder 1997), Lake Poygan - Winnecome basin (Priegel and

Wirth 1978), Black Lake (Baker 1980), Nelson River (Sopuck 1987), Lake Wisconsin

(Larson 1988), Groundhog and Mattagarni Rivers (Nowak and Jessop 1987), Kenogami

River (Sandilands 1987), Moose River (Brousseau and Goodchild 1989), and the

Frederick House, Abitibi, and Mattagami Rivers (Payne 1987). Estimates of biomass or

standing crop are more usefiil as a cornparison between systems. Sadilands (1987)

estimated biomass in the Kenogami River to range fiom 3 to 14 kgha. Biomass varied

between regions within the system. Payne (1987) reported estimates of 14 and 22 kgha

on the Frederick Houe River, 7 kgn?a on the Abitibi River and 2 k g h on the Mattagami

River. Brousseau and Goodchild (1989) also cornpared lake sturgeon standing stock on

these three rivers as well as the Groundhog River. They concluded that healthy lake

sturgeon populations existed on the Frederick House, Abitibi, and Groundhog Rivers-

The population on the Mattagami River existed in low numbers. Estimates of 68,23, and

16 k@ha were reported for three regions of the Menominee River (Thuemler 1997).

The objectives of this study were; 1) to compare the growth, population and

biomass estimates of lake sturgeon in a small isolated popdation (Round Lake, Pigeon

River) and a remnant population of what was once a major sturgeon river extending

Lake of the Woods to Lake Winnipeg. 2) to determine the distribution of lake sturgeon,

in a mature reservoir, relative to the gradient caused by the bachp of water due to

impoundment.

MATERLALS AND METHODS

Study Area

Round Lake is located on the Pigeon River which flows fiom Family Lake to Lake

Winnipeg (Figure 5). The study area included Round Lake and the Pigeon River upstrearn

&orn the lake to the e s t set of fds and downstream of the lake to the 6rst set of fds .

The Winnipeg River flows fiom Lake of the Woods in Ontario to Lake Winnipeg

(Figure 6). There are six hydroelectric dams on the river- The area between Seven Sisters

and Slave Falls dams and between Slave Falls and Pointe Du Bois dams were the focus

areas on the Winnipeg River.

Round Lake, Seven Sisters - Slave Falls, and Slave Falls - Pointe Du Bois, were

treated separately for this study. Growth, population estimates, and distribution for ail

three systems were determineci and compareci.

Age determination

Data €'rom the Winnipeg River for 1983-1995 were collected by J i Beyette

(Department of Natural Resources). Data collected from 1996 to 1998 were collected in

conjunction with Jim Beyette. Lake sturgeon caught in the WiMipeg River were aged by

the Department of Natural Resources except for the October 1998 catch. The Round Lake

samples and the October 1998 samples were aged as follows: The k t ray of the pectoral

fin was used for agùlg. A knife was inserted between the first and second ray to separate

the rays and'then the outerrnost ray was removed fkom the fin.

Figure 5. Map of the Pigeon River from Farnily Lake to Lake Winnipeg

Figure 6. Map of the Winnipeg River from the ~Manitoba Ontario Border to Lake W i p e g

A keyhole saw blade was used to remove the first ray. Salt was applied to the lin to reduce

chances of infection The fins were placed in labeled envelopes and allowed to dry- An

Isomet low speed saw was used to section fins. The jagged section of fin was removed as

close to the base as possible leaving a flat surface. Sections of 4O,4S, and 50 micrometers

were removed and placed in alcohol to dry. The fin sections were placed on glass slides

and mounted using Shandon-rnount toluene base mounting solution (Shandon, Pittsburgh,

PA). Growth ~ g s were counted using a dissecting microscope (Wdd Leitz Canada LTD,

Ontario, Canada)-

Growth Cornparisons

Age versus mean fork length was plotted to Msuaily compare growth between the

three study sites. Data fiom Lake Wmebago (Priegel 1973), Sipiwesk Lake (Sopuck

1987), La Grande River (Magnin 1977), and the Saskatchewan River (Haugen 1969) were

included to compare with data presented in figure 2. Age-length data from the three study

sites and the seventeen sites presented in figure 2 were analyzed to determine ditFerences

in growth. A Waiford plot (length(t) vs length(t+l)) was used to determine K (Brody

growth coefficient) and Lirdinity for the 20 data sets. Andysis of covariance was used to

compare diierences in dope (growth) and the intercept (maximum body size) between the

20 data sets. The data used for the Walford Plots was used in the Andysis of Covariance.

Figure 7. Lake sturgeon populations compared for growth rates using analysis of covariance. Sites 1-3 are Round Lake, Seven Sisters-Slave Falls, and Slave FalisPointe du Bois respectively. Sites 3-20 correspond to the data sets in Appendix 2.

Population Estimrtcs

The Round Lake sturgeon were tagged using PIT (AWD microchip ID system,

California) tags in 1996 and 1997. Fioy tags fiom the Manitoba Department of Natural

Resources were used in 1998. Each PIT tag is indïviduaiiy numbered giving a unique identity

to each fish. PIT tags were inserted under the fourth sute using a hypodermic needle to

puncture the skin and push the tag into place-

Data fiom the Seven Sisters-Slave Falls system was used fiom 1991-1998 because

only floy tags have been used since 199 1. Prior to this several diftierent types oftags had

been used with varying success. AU data from the Slave Fds-Pointe du Bois systern was

used because floy tags were used consistently throughout. The floy tags were placed on the

dorsal fin. Stainiess steal wire was inserted through holes in the numbered tag. Two

hypodermic needles were pressed through the dorsal fin of the fish. The wires of the tag were

fed hto the &les and through the dorsal h. The needles were removed and the wires were

twisted on using pliers. The Jolly-Seber estirnate of population sue was used for Round

Lake, Seven Sisters-Slave Falls and Slave Falls-Pointe du Bois.

Lake sturgeon distribution and density

The changes to flow and habitat caused by dam operation Vary over distance

upstream and downstream of a dam. Sections directly downstream wiU have higher aows

and may more closely resemble the natural flow of the river. Sections directly upstream

%di be more lacustrine due to impoundment by the dams. The two study sights on the

W ' ï p e g River were divided into sections dong the direction of flow from the dam to

compare biomass estimates in the section of the river h e e n the dams. A planimeter was

was used to divide the systems into qua i size sections based on surface ares- Round

Lake was divided into four sections (Figure 8). Each section was 73 ha. Seven Sisters-

Slave Falls was divided into 12 sections (Figure 9). Each section was 421 ha. Slave Falls

- Pointe du Bois was divided into 4 sections (Figure 10). Each section was 174 ha. Mean

depth was estimated for each section by ninning transects across the river and averaging

depths for al1 transects.

Three nets (12", Y, and standard gang - 1-25", 2", 2-75", 3 .Y7 4.25" and 5"

stretched mesh) were set in each section of each study sight on two separate occasions (a

total of six nets per section). Catch per unit effort for each section was calculated by

dividing the total number of sturgeon caught in all six nets by the total number of hours

al1 six nets were set. Fish density for each section was calculated using the population

estimates, catch per unit effort, and surface area or volume. Analysis of Variance was

used tu compare mean weight between sections in each system and an overall

cornparison between systems. Dismbution of lake sturgeon using density was compared

between sections in each system using a chi-square test.

Figure 8. Map of Round Lake designating blocks 1 to 4 used for lake sturgeon sampling

Figure 9. Map of the Seven Sisters-Slave Falls region of the Winnipeg River designating blocks 1 to 12 used for lake sturgeon sampling

Figure 10. Map of the Slave Falls-Pointe du Bois region of the Winnipeg River designating blocks 1 to 4 used for lake sturgeon sampling

Pointe du Bois Dam

Slave Falls Dam

RESULTS

The age-length data of lake sturgeon fiom the three study areas (Figures 8,9, 10)

is simiIar to that of Sipiwesk Lake, greater than that of the La Grande River, and less than

that of Lake Wimebago and the Saskatchewan River (Figure 11)- The parameters of the

von Bertalan.n@ growth curve for the 20 dam sets are presented in table 3. The covarïate

was not significant (P=0.611) therefore the growth was different between lake sturgeon

populations fiom each site. L inflnity (maximum body size ) was also signicantly

diEerent (P=O.OO).

Population estimates in Round Lake range fiom 800 to 1050 lake sturgeon in

1997 and 1998 (Table 4). Estimates on the Winnipeg River range fkom 400 to 1 100

between Slave F d s and Pointe du Bois and range fiom 3000 to 26000 between Seven

Sisters and Slave Falls (Table 4).

Mean weight between sections in Round Lake was significantly different

(P4.00). Mean weight was higher in section 3 than sections 2 and 4 and lower in section

4 than in section 1 (Figure 12). Biomass in Round Lake is higher in sections 1 and 3 than

in sections 2 and 4 (Table 5).

Figure 11. Cornparison of growth of lake sturgeon nom Round Lake, Seven Sisten-Slave Falls, Slave Falls-Pointe du Bois, Lake Winnebago (Priegel 1973), Sipiwesk Lake (Sopuck 1987), La Grande River (Magnin 1977), and Saskatchewan River (Haugen 1969).

Table 3. von Bertalaaffl growth parameters for Round Lake, Seven Sisters-Slave Falls, and Slave Falls-Pointe du Bois, and the 17 data sets presented in figure 2). . .

Location

Round Lake Seven Sisters-Slave Falls

Slave Falls-Pointe du Bois Lac des duex Montangues

Lake St. Francis Lake Winebago a

Michigan Lake St- Pieme

Menominee River Sipiwesk Lake b Kenogami River

Saskatchewan River, AB Saskatchewan River, SK

Lake Winebago b Flambeau River Lake St. Louis

Sipiwesk Lake a Mattagarni River

Moose River La Grande River

Table 4. Population estimates and 95% confidence intervals for lake sturgeon in Round Lake, Seven Sisters-Slave Falls and Slave Fails-Pointe du Bois.

Location Time Estimate Lower CI Upper CI

Seven Sisters-Slave Falls 1992 10259 3794 46239

1993 27374 531 7 326827

1994 928 1 4239 30183

1995 26008 1141 1 89742

1996 15708 6857 54732

1997 2998 1143 13101

Slave Falls-Pointe du Bois 1994 360 186 2903

1995 1100 498 71 54

1996 1015 505 8393

1997 648 356 6676

Aug 97 1 054 390 3866

Sept 97 796 356 2020

Aug 98 916 410 2325

Sept 98 997 534 2427

Oct 98 1 048 562 2553

Round Lake

Table 5: Lake sturgeon data table for Round Lake, Seven Sisters-Slave Falls, and Slave Falls-Pointe du Bois.

Round Lake Section mean wt CPUE (fishlhour) fishlsection dendty (kglha) density (kgim3) denisty(fish/ha) density(rishlm3)

1 6.4 0.1 1 246.67 21.63 0.20 3,38 0.03 2 2.1 0.06 148.00 4.26 0.04 2,03 0.02 3 7.7 0,08 172,67 18,21 0,17 2.37 0,02 4 2 0.20 394.67 10.81 0.M 5.41 0.03

Seven Sistem - Slave Falls Section - f i a n wt C ~ E (fiihlhour) fishlsection deniity ( m a ) deniiîy (k9im3) denirty(nshni8) deniity(Rlhlm3)

Slave Falla - Pointe du Boia - - -. - - - - - - - - - - - - - - -

M o n m a n wt CPUE (flshniour) fidi(section &nslty (kglha) dendty (kglm3) denisty(fiih/ha) dsnaity(fihhn3) 1 2 0.03 51,89 0.60 0.00 O. 30 O. 00 2 2.6 0.19 259.44 3.88 O. 02 1,49 0.01 3 7.9 O. 16 285.38 1236 0.09 1.64 0.01 4 8,2 0,20 3 2 4 3 15,28 0,08 1.86 0,Ol

Ovarall Comprriion m a n wt CPUE (flrhlhour) firW8oction &niNy (kglhr) danrity (kglm3) deniity(fiahnia) denaity(fiihlm3)

Round 3.7 O, 12 240.5 12.1 O, 1 3.29 0,029 Seven 4.2 0.17 976.9 9,75 0.13 2.32 0.03 Pointe 6.2 0,14 230.3 8.2 O. 05 1.32 O. 008

Figure 12. Mean weight cornparisons of lake sturgeon between sections in each study site and between overall means of each study site. Horizontal line indicates overall mean of al1 sections combined- Sections with the same letter were not significantly different (Tukey's test, @.OS)

-- S..

Catch per unit effort and density was higher in sections 1 and 4 than in sections 2 and 3

(Table 5). Distribution of lake sturgeon was not significantly different from random

between the four sections in Round Lake (P==O. 10 1).

Mean weight in sections 10,11, and 12 in the Seven Sisters - Slave Falls system

was signifcantIy dserent (W.00) . Mean weight was Lower in sections 11 and 12 than

in section 10 (Figure 12). Sample size was too srna11 in sections 4,6,7, and 8 to test for

significant differences but al1 fish caught in these sections were large fish. No lake

sturgeon were caught in sections 2,3 ,5 , and 7. Al1 values were zero for these sections.

Catch per unit effort, biornass, and density were highest in sections 10, 1 1, and 12 (Table

6). Biomass was highest in section 10 and density was highest in sections 11 and 12

(Table 5). Distribution of lake sturgeon was different fiom random (P4.00).

Mean weight in the Slave Falls - Pointe du Bois system was significantly

different (W.00). Mean weight was lower in sections 1 and 2 than in sections 3 and 4

(Figure 12). Catch per unit effort, biomass, and density was lowest in section 1, sections

2,3, and 4 were similar regarding ail three measurements (Table 5). Distribution of lake

sturgeon was different fiom random (P=O.OO).

Mean weight was not signincantly difTerent between Slave Falls - Pointe du Bois,

Round Lake, and Seven Sisters - Slave Falls (W. 1046; Figure 12). Biomass and density

were lower in Slave Falls -Pointe du Bois than in Round Lake and Seven Sisters - Slave

Falls (Table 5).

The age-frequency distribution in Round Lake shows good recniitrnent as there

are a large proportion of fish under the age of ten (Figure 13). The Seven Sisters - Slave

Falls system show less recruitment as there is a small proportion of fish under ten years

of age and the majonty greater than nfteen years of age. The Slave Falls - Pointe du Bois

system shows a more even distribution. There appean to be good recruitment and a high

proportion of fish of reproducing age. A decline in the frequency distribution occun

between 13 and 17 years of age. This may be due to severai years of disruption ui

spawning due to abnormal flows or temperatures. The age kquency of the lake sturgeon

population in Seven Sisters-Slave Falls indicates a population with an increasing

proportion of older larger fish. The median and meau age is increasing over time (Figure

14)-

Figure 13. Age frequency distribution of lake shugeon for al1 three systems.

Round Lake 12

mven Sister, - Siave Falls 100 -,

Slave Falls - Pointe du Bois 18

Figure 14. Age fiequency distribution of lake sturgeon between Seven Sisten - Slave falls over three tirne periods.

DISCUSSION

Hydroelecûic developrnent is thought to have a major impact on sturgeon

populations throughout its range. Both reservoirs studied on the Winnipeg River are

mature therefore short tenn affects of impoundment such as nutrient loading will not be

expected Blockage to migration and loss of spawning and rearing habitat are long term

affects that are likely continuing to impact on sturgeon populations

There was no difference in growth between the population in Round Lake and the

two populations on the impounded Winnipeg River. Furthexmore, growth differed

between the twenty data sets aaaiyzed. Growth was higher in lake populations such as

Lake Winnebago, Lac des duex Montangues, Lake St. Francis, and Lake St. Pierre than in

river populations such as the Flambeau, Mattagatni, Moose and La Grande Rivers. Some

of the cornparisons can be related to differences in latitudinal distribution. A closer look

at populations in the same area show a sirniiar pattern. Flambeau River is in Wisconsin

but shows lower growth than the Lake population in Lake Winnebago. The lake

populations along the St. Lawrence show faster growth than river populations in Ontario

of similar latitude. The large productive lakes appear to provide more potential for

growth than rivers.

The distribution of lake sturgeon may be related to the changes in flow as the

river becomes impounded following the building of a dam. The high water levels above

Seven Sisters dam affects the river up to Otter Falls (see section 7; Figure 9). This is

based on the observation that at both Otter Falls and The Barrier (see section 9; Figure 9)

there is stili substantial current. However the first major &op on the Winnipeg River

between Seven Sisters and Slave Falls occurs at Sturgeon Falls. Above Sturgeon Falls the

river has not changed and continues to be the natural flowing river. There are areas of

strong current and rapids, with areas of slower cwrent and back eddies in bays dong the

shore. The highest density of lake sturgeon between Seven Sisters and Slave Falls was

found in the sections 10, 11, and 12 upstrem of the affected areas. Densities below

Sturgeon Falls were very low with many sections containing no lake sturgeon. By

contrast, the entire area between Slave Falls and Pointe du Bois is essentially an

impoundment but with considerable flow as the area is too small to store a substantial

volume of water. DiEerences in density and biomass were less pronounced and density

and biomass estimates were lower for Slave Falls-Pointe du Bois than in Round Lake or

Seven Sisters-Slave Falls. These observations M e r support that even mature

impoundments affect lake sturgeon numbers and distribution. However, as this is a

mature reservoü of some yean, it appears that new recruitment is occurring suggesting

that the lake sturgeon population may be stabilizing. This population however may not

reflect al1 impoundments but is rather a reflection of two generating stations close

together, a low storage capacity and contùiuous strong flows through the system, in other

words a "flowing reservoir".

The distribution of addt and juvenile lake sturgeon was different in al1 three

systems. The distribution of larger lake sturgeon appears to be more widespread in the

Seven Sisters-Slave Falls system. Large sturgeon may be more tolerant to different

habitat conditions or able to swim longer distances in searcb of food. Hïgh densities of

small lake sturgeon were found in those areas that were essentially unperturbed following

impoundment but very few small sturgeon were found outside this region. By contrast, in

Round Lake the smaller lake sturgeon were found in the sections ofthe lake and in the

vicinity of the inlet and outlet: ie. where there was strong flow.

Densities of lake sturgeon reported in the literature varied fiom 1-2 kgfha on the

Mattagarni River to 68 kg/ha on the Mewminee River. Numao lake (Section 1 1) on the

Winnipeg River, below the Slave Falls dam had a density estimate of 41 kgha but the

overall estirnate for the entire section of the Winm-peg =ver was 10 kg/ha The study

sites had lake sturgeon populations sùnilar to those presented in the iiterature.

The age distribution of the Seven Sisters-Slave Falls region indicates an aging

population. It is difficult to explain the loss of intermediate sized lake sturgeon (15 to 20

kg) over time fiom the section of the Winnipeg River. Whether this is due to natural

mortality or selective removal of a certain size class is unktlown but the latter seems

more likely than the former. No large die offs of lake sturgeon have ever been reported

but removal of tish ftom the system could lead to the size class distribution reported here.

The removal of sturgeon in the 15-20 kg range could lead to changes in age structure as

younger fish are removed nom the population often before they have spawned for the

first time. Looking at the overall age fiequency for this system there are very few small

fish indicating poor recruitment. By cornparison the Round Lake data indicates very few

older fish which translates into fewer than 15 fish old enough to spawn. The number of

juvenile fish in the system indicates that spawnùig is occming but the population is

Milnerable to any fiom of exploitation. nie removal of a single adult fish could result in

the loss of an entire year class.

In sumrnary, the relatively pristine Round Lake system has a developing lake

sturgeon population with good recruitment of small size classes. However, the access to

the lake durhg the winter, through the winter road, has resulted in the loss of addt fish

and a population quite vulnerable to any M e r fishùig.

The two areas studied on the Winnipeg River represent mature impoundments but

they differ in there overall structure. The Seven SistersSlave Falls section has much of

the original river flooded with ody a srnail section similar to preimpoundment

conditions. Consequently the population is highly concentrateci in the upper reaches

where normal flows occur. The Slave Fails-Pointe du Bois section is essentially a flowing

reservoir due to the proximïty of the two dams and the low storage capacity and this has

allowed a sturgeon population to establish and sorne recruitment is occurrîng.

CHAPTER 2. Movement and Habitat Utilization of lake sturgeon in Round Lake.

INTRODUCTION

Sturgeon movernents have ken studied by several investigators (Basset 1982,

Leclerc 1984, Swanson and Kansas 1987, Hay-Chmielewski 1987, Swanson et al 1988,

Thuemler 1988, Swanson et al 1990, McKinley et al 1991, Mosinây and Rusak 1991,

MacDonell 1992, Rusak and Mosindy 1997, McKinley et al 1998)- Emphasis on these

studies bas been on large stutgeon and trying to asses the extent of their movernents. It is

ofien unclear, in these studies, the purpose or value of knowhg that large sturgeon move

great distances while others move relatively short distances. Other than detennining

spawning sites, which most Aboriginal comrnunities have h o w n for hundreds of years, littie

emphasis was placed on understanding the activity of juveniles in any system.

Hay-Chmie1ewski (1987) found radio telemetry difficult in deeper water and therefor

used acoustic teiemetry to monitor the movements of lake snirgeon in Black Lake. The focus

of the study was to compare movements with available habitat These fuie scale movements

are essential to understand sturgeon biology.

Habitat selection and movement of juvenile sturgeon have rarely been documented

Young hatchery reared lake sturgemn were released into the Menominee River, Wisconsin

and monitored using radiotelemetry (Thuemler 1988). These fish seemed to move

continuously downstream. This was possibly due to their origin fÎom the hatchery, unable to

cope with the externai variables or the tag size to body weight ratio.

Habitat use and movements of shovelnose and shortnose sturgeon have been studied

by radiotelemeûy (Hutley et al 1987, Hall et al 1991, Curtis et al 1997, Buckley and Kynard

1985). Sonic telemetry has been used to study the movements of shortnose, Atlantic and

white sturgeon (McC1eave et al 1977, EW et al 199 1, Kieffa and Kynard 1993, O'bemn et

al 1993, and Moser and Ross 1995). As with lake sturgew, seasonal migrations and long

range rnovements were studied Several studies also focused on fine scale rnovements and

their relation to habitat perameters such as substrate and fiow. Hiil et al (1991) used SCUBA

divers on the Savannah River to get a visual look at the suspected spawning grounds of

shortnose sturgeon and took substratte samp1es at suspected feeding sites. The spawning and

feeding sites were detemineci by radio and awustic telmeüy. Curtis et al (1997) measured

depth, temperature, and substrate at each telemetry location of shovehose sturgeon in the

upper Mississippi River- Wing dams and closing dams were found to be important structures

for shovehose sturgeon in the upper Mississippi River diiriag periods of high fiow (Hurley et

al 1987). Observations such as these are important in detennining fine d e use of habitat by

these fish as habitat is a critical factor in the survival of any species. The way in which

river ecology is modified through human impacts may be changed if there is a better

understanding of preferred habitat, especially for feeding.

Determining optimal habitats at dl stages in the life history of a species is

essential to its sunival. Amustic telemeûy is a good tool to aid in the detemination of

habitat selection. The objectives of this study were to evaluate habitat use of lake

sturgeon in an unperturbed environment as it relates to depth and substrate.

MATERIALS AND METHODS

Lake sturgeon movement data in Round Lake is presented by (Begout-Anras et al

in press). Appendix 2 illustrates general patterns of movement by 9 lake sturgeon tagged

with sonar tags and followed for 28 days in Round Lake.

Depth and Substrate Hardness

Depth and substrate maps were generated by Habitat Consulting Services. Briefiy,

the substratum data consisted of the collection of data using an Amencan Pioneer V

digital sonar system and a Trimble Pro XR submetre Global Positioning System. Sonar

daîa was collected using a 120 kHk - 12 degree t r d u c e r . Information coilected

included depth, bottom hardness and roughness. Bottom hardness is an interval measure

of the magnitude of the sonar ping r e m signal. Larger byte range values indicate a

harder substrate. The depth and substrate uiformation collected above was done in

September 1997. Creation of al1 maps and the calcuiation of available habitat was done

on Idrisi for windows. A fiequency distribution was created using the data from each

pixel on the hardness and depth images.

Sediment Analysis

Sediment grabs were taken in September 1997 at the time of the collection of

sonar data and in August 1998. Ten grabs were taken in 1997 and 27 grabs were taken in

1998 (Figure 15, Table 6). The purpose of the sediment grabs was to compare sonar data

results with actual sediment taken fiom the lake.

Figure 15. Round Lake depth contours (lm), location of the 37 sediment grabs taken in 1997 (A-H) and 1998 (1-27), and the locations of the two buoy anays (black triangles) used for acoustic telemetry.

Table 7: Sediment grabs taken fiom Round Lake in 1997 and 1998.

1997 Round Lake Sediment Grabs Grab Mean Phi Class by Sieve Hardness

A 3 fine sand 110 very fine sand medium sand

Silt very fine sand

Silt fine sand fine sand Pebble Rock

1998 Round Lake Sediment Grab Grab MeanPhi Class by Sieve Hardness

Silt very fine sand

Silt Silt Silt

very fine sand very fine sand coarse sand

Silt fine sand Cobble Rock

Pebble Pebble

medium sand Rock

Pebble Gravel Rock Silt Silt Silt

Pebble Pebble

medium sand Silt

G rave1

From this data a substrate type: silt, sand, cobble, etc., could be matched with hardness

values produced fiom the sonar data.

Field Methods

Sample sites were selected so that all possible substrate types were represented.

Transects were nui across the depth gradient in the Iake ninning nom the shallow sandy

areas to the deeper siltfclay areas. Current was considered when s e k c ~ g sarnple sites.

Areas of high and Iow current were sampled.

Buoys were placed at the spot to be sampled The location of each sample was

recorded in geodetic position using a GPS unit. An Eckman dredge was dropped at the

buoyed site and the sample retrieved The sample was placed in a bag and kept cool until

it could be tested in the lab.

Lab Methods

The total sample at each site was divided into three parts. 100 ml was taken for

particle size analysis, 100 ml was taken for invertebrate sampling and the remaining

portion (if any) was frozen.

Particle size analysis

Grave1 and larger parîicle sues were separated individually by hand, sieve

analysis was used to separate the portion of the sample in the very fine sand to grave1

categories, and settling velocity was used for silt and clay particle sizes.

The sample was placed in a tray and rnixed thoroughly and then added to water

and dispersent (Calgon-sodium hexarnetaphosphate), mixed again, and let sit ovemight.

The sample was then mixed, fiozen, thawed and mixed again The process was repeated

a second time to ensure that the particles were completely separated. M e r the sample

was separated thoroughly the silt and clay particles were removed fiom the saud and

grave1 particles. The sample was wet sîeved through a 4 phi sieve to remove the silt and

clay fiom the sample. The sediment lefi in the 4 phi sieve was placed in a beaker and the

sediment passing through the sieve was collected in a separate container. Fine and larger

particles were treated separately.

Sand sample

The sampie was placed into a pyrite beaker and aiiowed to completely dry in the

oven. A pestle and mortar were used to break up any chunks formed during the drymg

process and the total sample was weighed and placed in the top of a series of sieves

ranging fiom -1.5 phi to 4 phi (0.5 phi intervals). The sieves were then placed into a Ro-

tap shaker and the sieves were shaken for ten minutes. The material in each sieve was

weighed and recorded.

Siltlclay sarnple

The silt/clay sample was placed in a 4000 ml graduated cylinder. Water was

added to the cylùider to make the total solution 4000ml. The solution was then shaken

thoroughly and allowed to settle until silt separated nom clay. Five phi (1/32 mm)

particies are the largest size category and were removed first. Five phi @cles settle at a

rate of 4 mm/second The 4ûûûml suspension is 500m.m hi& therefore the suspension

was allowed to settle for 6 minutes and 15 seconds to allow all 1/32mm particles to setîle

the fui1 depth of the water in the cylinder. The supernatant (water and particles smaller

than 1/32mm) was siphoned off and saved. This process was repeated twice more to

remove any smaller particles that would seale from the bottom portion of the cylinder.

The rernaining precipitant after the third siphon was dried and weighed as the silt

category. The siphoned water was dried and weighed as the clay category.

Sediment classifi.cation

The particle size classification used was Cummins (1962) modification of the

Wentworth Scale. Thirty-seven sediment grabs were taken and analysed fiom Round Lake.

GPS locations for the sediment grabs were compareci to hardness values fiom the Round

Lake map at the same GPS location. nie classifkation ofeach sedùnent grab was compared

to hardness values at each location obtained by sonar. A classification scheme was created

combining the sonar and sediment grab &ta (Table 7).

Table 8. Sediment classification scheme for Round Lake. Classifications were based on a cornparison of sonar and sediment grab data

Phi Particle Size (mm) Catego~ Hardness

9 <0.0039 Clay 95

5,6,7,8 0.0039 - 0.0625 Silt 100

4 0.00625 - 0.125 Very fine sand 1 05

3 0-1 25 - 0.25 Fine sand 110

2 0.25 - 0.5 Medium sand 115

1 0.5 - 1 Coarse sand 120

O 1 - 2 Very coame sand 125

-1 ,-2,-3 2 - 1 6 G ravel 130

-4,-5 16-64 Pebble 135

-6, -7 64 - 256 Cobble 140

-8 ,256 Boulder 145

Acoustic Telemetry

Gill nets of three different sues: 30 cm, 22.5, and a standard gang with six panels

(3.1,5,6.9, 8.8, 10.6, 12.5 cm) were used to capture al1 lake sturgeon. Fish were brought

to shore and placed on a damp canvas sheet. Acoustic tags were attacheci extemally to the

dorsal fin. A piece of aeoprene was placed between the tag and the dorsal fin and a piece

of neoprene was placed on the opposite side of the fh for support of the attachent

wires. Two hypodennic aeedles, spaced apart the length of the tag, were pushed through

the neoprene backing and then through the dorsal fin of the fish. The attachment wires

were threaded through the tag, through the other piece of neoprene, and then inserted into

the needles. The needles were then removed drawing the attachent wires thmugh the

fin and the neoprene on the opposite side of the fin. The attachment wires were pulled

snug and several knots were tied to secure the tag. The excess wire was cut. Al1 twls

were sterilized before use and salt was applied to the tagged area d e r the procedure to

reduce infection.

Two types of acoustic tags were obtained fiom VEMCO Ltd. (Halifax, Nova

Scotia). Three large fish were tagged with V16 pressure tags, the remaining seven fish

were tagged with V8 position tags. Pressure tags transmitted information on swiming

depth as well as positional information. The V8 tags transmitted positional data. The tag

weight to body weight ratio for both radio and acoustic telemetry was less than 1% for al1

fish.

Fish tracking was done using two radio linked acoustic positionhg amys (VRAP,

VEMCO Ltd-). Each anay coasisted ofa base station that communicated with each of

three buoys anchored in the lake. Each buoy contains an acoustic transmitter, an

omnidirectional hydrophone and a VHF modem-

Buoy location was determined using survey techniques. The chosen positions

covered 80% of the surface area of the lake (Figure 15).

Telemetry Data

Telemetry data analysis and presentation was done using Idrisi for Windows

(Clark University, MA). Ail maps were created in Idrisi for Windows. Acoustic telemetry

data were imported fiom the VEMCO system program by Mdm Begout-Anras.

Swimming depth was plotted as a fiequency distribution based on the data

retrieved fiom the depth tags. Spatial movement images and the depth image were

compared to determine the depth of water that an individual fish were swimming in.

Seven days were selected for anaiysis of substrate selection. Days 206 and 221

were selected for sturgeon 4014. Days 2 10 and 222 were selected for sturgeon 4015.

Days 206, 21 1 and 219 were selected for sturgeon 4017. For each location on each day

bottom depth was determined Swimming depth minus bottorn depth was calculated to

determine al1 locations in which the fish was in contact with the substrate, Al1 values of 1

or less were included AU figures and comments pertaining to substrate selection only

include locations in which the fish was in contact with the bottorn. Other locational

staternents and figures use al1 positional data available. A Chi-square goodness of fit test

was used to compare substrate availability with substrate selection.

Substrate and Depth

There are two deep basins in Round Lake reaching 16m, with shallow shelves

towards the shoreline and a fluvial channel nuinuig generally fiom the det at the Southeast

comer to the outlet in the Northwest corner (Figure 15). Substrate hardness ranges fiom 90 to

150 (Figure 16). A Cornparison of the sediment grab data with sonar data for substrate

hardness showed a correlation with high hardness values and large particle substrates and

low hardness with low particle sizes from the grabs. Substrate was generaliy related to depth.

The deeper areas of the lake had softer substrates with a high percentage of silt Sample

points 1-7 are al1 finer particle substrates (Table 7). Flow is reduced releasing the f'her

particle sizes. Sample points I, J, 11, 13, 14, 15, 16, and 27 are all in the vicinity of the inlet

where high flows are expected (Figure 15). Particle sizes in al1 these sample points are larger

ranging fiom pebble to rock Sample points B and 10 are finer perticle sizes indicating that

flow is reduced in these areas. The fluvial channel proboibly runs between these two sampling

points. Sarnple points D and E are fine particle sizes and are fiom the deepest part of the

basin where sedimentatou is expected Sample points 20, 21, and 22 were just outside the C

main chanwl or just prior to where flow increases. Sample points 23, 24, and 25 containeci

larger particles sizes as they were just inside the outlet h m the lake.

Figure 16. Hardness map of Round Lake with depth contours. Values range fiom 95(lightest brown) to 150 (darkest brown).

Movernents

Nine lake sturgeon were tracked for 27 days and 15446 locations were obtained. The

lake sturgeon ranged in size fiom 506 to 16900g (Table 8). Movements for individual fish

ranged from highly sedentary to highly mobile, daily movements were variable between fish

as well as by the same fish on different âays. The majority of movernent by lake sturgeon

was seen at the inlet and outlet and dong the deeper contours of the lake where higher

currents are expectd Movernent was generaiiy related to CPUE that was highest in sections

2 and 4 including the inlet and outiet.

Depth selection was quite variable between fish (Figure 17). LS4011, LS 4013, and

LS4017 selected water depths generally pater than 8 meters. LS4010 had an even

distribution of swimming depths between 2 and 13 metes. LS4014, and LS4015 selected 2

meters depth considerably more than any other. LS4012 and LS4009 selected shallower

water generdly less than 8 meters. There was little ciifference in depth selection of large and

small lake sturgeon (Figure 18). Large lake sturgeon seiected 2 meters more often than the

other lake sturgeon, ppllnarily because of the 2 fish mentioned previously. The remainder of

the fish were generally spread over 2 to 15 meters depth. Overail, lake sturgeon were

generally located in 7 to 10 meten of water (Figure 19A). Swimmiog depth for the three lake

sturgeon with depth tags was generally Les than 4 meters, thirty percent of d l locations were

less than two meters, sixty-six percent were less than four meters (Figure 19B). Swimming

depth when in contact with the substrate was highiy seleetive at 7 to 10 meters (Figure 19C).

Depth availability is highest at 2 to 3 meters (Figure 19D). The fiequency of substrate

selection is highest at a harciness of 110 substrate availability is highest at a hardness of 130-

135 (Figure 20). The neqUency of lake sturgeon substrate selection is different than the

fiequency of substnite availability in Round Lake (chi-square = 62598; criticai value x ~ ~ ~ ~ ~ , ~ ~

= 7.26 1).

Table 8. Lake sturgeon data for the acoustic tagged fisb

Number Total length(crn) Fork Length(cm) Weight(g) Age

4010 54 48 632

401 3 49 44 572

401 1 49 45 562

4012 48 43 506 4

4014 143 1 28 16900

4015 125 117 13250

4016 138 1 26 14750 31

401 7 119 113 11620

4009 101 95 6790 22

Figure 17. Depth selection of the individual lake sturgeon in Round Lake.

Figure 18. Depth selection of large (LS4009, LS4014, LS40 15, LS4O 16, LS4017; 67908 - 16900g) and small (LS4010, LS4011, LSQ012, LS4013; 506g - 632g) lake sturgeon in Round Lake.

Figure 19. A) Depth selection of al1 9 lake shirgeoa B) Swimming depth of the tbree Iake sturgeon tagged with depth tags. C) Swimming depth of lake sturgeon when in contact with the substratte. D) Depth availability in Round Lake.

Figure 20. Substrate selection of lake sturgeon and substrate availability in Round Lake.

DISCUSSION

Two considerations that mut be addmsed in d e s dealïng with tagged fish are 1)

the effects of handling and 2) tag weight Our observations were similar to Hay-Chmielewski

(1987) who found that the released lake sturgeon would move to the centre of the river and

remain there for up to 6 hours. Al1 fish in Round Lake were released ffom shore Uito shaliow

water, 1-2m, where the fish were visible often for several hours. Since there was no increase

or decrease in movements related to the length of time after release, d l movernents after the

fish left the shallow water were assumed to be normal. In addition, the CPUE data found

very similar distributions h m data cdected with gill nets to the data h m the wmbined

movements of the tagged sturgeon using sonar tap.

The tag is assumed to have no effect on behaviour. Tag weight relative to body size

may alter a fish's movement We assume tag weight had no effect on sturgeon movements

because the tag to body weight ratio of the fish in this s tdy was much l e s than the 1-2%

recommended by Winter et al (1978) and Hocutt (1989). The lake sturgeon studies done to

date have had similar tag to body weight ratios. Swanson and Kaasas (1987) and Rusak and

Mosindy (1997) had ratios ranging between 0.2% and 1.5%. Thuemler (1992) used tags that

were 2% to 3.5% body weight.

Subsirate and depth wre the two primary environmental variables measured in this

study. Scott and Crossman (1973) state that the protmsible mouth obviously adapts

sturgeon to feeding on the bottom. The majority of studies on the feeding habits seem to

agree with this conclusion. Harkness (1923) coacluded that sturgeon feed on the most

abundant bottom organism available without preference. Fish and vegetation have been

found in the stomachs of some lake sturgeon (Hanis 1952, Glover 1961, Haugen 1969,

Paetz and Nelson 1970, Love 1972, Eddy and Underhill 1976, Saunders 1981, Sandilands

1987) indicating that they do not feed entirely on invertebrates. Since benthic organisrns

are associated with different substrates it follows that lake sturgeon may occur more

fiequently on or over these substrates. On the other hand if benthic invertebrates are not

restricted to one substrate type but will select preferred substrates depending on

requirements for shelter, respiratory needs, and food habits (Ward 1992) then the activity

of lake sturgeon may help us determine optimum feeding ranges.

The general movements of the lake sturgeon were similar to that seen in other

studies. Lake sturgeon movernents ranged moving short distances to extreme

movements up to 27bn in a single &y (Begout-Anras et al; Appendix 3). Movements in the

areas of the inlet and outlet, areas of higher flow were quite common as weil as movements

in the deeper parts of the lake and dong the natural riverbed in the lake. Movements close to

the shore were rare. Along the shore the water is shailow, there is liale flow, and the

substrate is primarily sand or rock (exposed areas of the lakeshore). Interestingly, there are

smaller areas close to shore with a mix of boulders, cobble, and pebble tbat did not seem to

be frequented by sturgeon,

Based on the cornparison of substrate selection and substrate availability lake

sturgeon were found over very fine & and medium sand substrate more fiequently than

these substrates occur in the Me. Coarse sand and grave1 substrates as weli as cobble and

pebble substrates were selected at lower hquencies than these substrates are found in the

lake. An understanding of substrate preference of lake sturgeon and substrate preferences of

the prirnary prey species may help us understand prey selection. Lake sturgeon are hown to

feed primarily on benthic in~ertebraîes~ Hixqgeniu (Ephemeridae) is a common prey item of

lake sturgeon. Silt and clay substrates that are sofi but h n enough to mainttain a burrow are

the optimal habitat for Heurgenia (Edmunds et al 1976). Crayfish prefer habitats that aUow

concealment and wiU bide in crevices in areas of coarse substrate (Thorp and Covich 1991)-

Cobble substrates would allow large enough creMces for crayfïsh to hide. Clams are often

found in sandy substrates (Williams and Feltmate 1992). The selection of fine sand and

medium sand substrates by lake sturgeon indicates that they rnight be feeding on Hixagenia.

Clam shelis were often found in nets pulled fiom the ïniet and outlet where many movements

were seen- Clams may also be an important wmponent of the diet

The lake sturgeon spent a significant amount oftime in the water column and at the

surface. The arnount of tirne spent in the water column may indicate that they are feeâing on

organïsrns drifting with the currpnt or upwelling due to cornplex currents. A majority of

Iocations were related to the inlet and outlet where the cunent could be strong enough to

carry organisrns through the water. Lake sturgeûn tended to stay in the water column more

often in areas of high flow such as the inlet and odet but were in contact with the bottom in

deeper areas dong the contom of the lake. Since the sndy took place in mid summer

spawning behaviours or movernent related to falVwinter migrations were not a faîtor, the

majority of movements are probabiy related to feeding behaviour.

Another important cornparison in determinhg the habitat of lake sturgeon is the

cornparison of feeding habits with other fish species in Round Lake. Round Lake has several

fish species that feed on benthic rnacroinvertebrates (Chapter 3). Cornparisons between the

food habits of these species and lake sturgeon can lead to insights on another potentially

important aspect of habitat The feeding dynemics between lake sturgeon aad the other

common fish species in Round M e may lead to alterations in habitat selection, swimmiog

depths, and substrate seiection.

Choudhury et al (19%) found that the majority of food items in sturgeon h m Lake

Whebago were Daphnia. This suggests extensive feeàing in the water wl~~l l f~ Interestingly

sport fishers on the lake report sturgeon spiashing on the surfàce (Bruch pers. comm.).

Apparently lake sturgeon feed in the water column more fiequently than previously thought.

Kempinger (1996) reporteci that age-0 lake sturgeon were observeci by divers to orient

upstream in the current and feed on organisms drifting downstream.

Radio telemeûy was used in 1996, 1997, and 1998 to monitor Iake sturgeon

movements (Appendix 4). Movements were similar to that seen by acoustic telemetry. The

advantage of the radio tags was the iacreased ability to monitor movements in the river

upstream and downstrearn fiom the lake. The large amount of acoustic data however was

used to describe the more Eine scde movements and habitat selection

Cleaxly our understanding of sturgeon use of habitat and its feeding behaviour is still

lirnited Substrate is important but so is substrate in relation to stream flow. The possibility of

feeding on cmcentrated drift food items or sùnply feeding ui the water wlumn are likely

important in ce- aquaîic system. Finally the relationship to other fish species, conceming

space and food items consumed, especially where lake snirgeon do not dorninate the species

composition, may also change feeding patterns. On the b i s of defined populations today the

Round Lake system appears the best unpe- area to pursue this sort of question

CHAPTER 3. Growth and diet of the fish species of Round Lake.

106

XNTRODUCTION

In the previous chapter 1 show that substratte is important in determining lake

sturgeon biologicai needs. However, lake sturgeon habitat includes not only physical

panuneters such as substnite, current, and depth but also biological interactions with

other a q d c species. Cornpetition (Keast 1978; Tom 1985), predaîion (Conne11 1975;

Paine 1980; Gilinsky 1984), and prey seiection are important biotic factors a£kctkg the

structure of a fish community. Species interactions are dynamic and will cbange with fish

size, season and the availability of prey. Studies on species interactions should include al1

these aspects in order to obtain the best understanding of the systern a d to be able to @ci

interactions in other sy-. Aquatic food webs are generally d e s c r i i ! by placing

organisms into trophic levels. Root (1967) used the term guild to describe a group of

organisms that exploit the same resources in a similar way. There is substantial information

on the food habits of lake sturgeon, yellow perch, sauger, walleye, pike, mwneye, and

suckers in the literature (Scotî and Crossman 1973). Ail of these fish species are potential

cornpetitors for food of lake sturgeon because tbey are more Wrely as late juveniles and

adults, to consume food items of similar size and type to those preferred by juven.de and

adult lake sturgeon. Lake sturgeon feed on a wide range of invertebrates (Table 2), and

mayfiies belonging to the family Ephemeridae are a major food item for aü ages (Mosindy

and R d 1991).

Arnong the percids, yellow perch generally shifts nom feeding on zooplankton to

macrobenthos to fish as they grow (Clady 1974, Nakashima and Leggett 1975, Keast

1977, Hartmann and Numann 1977, Paxton and Stevenson 1978). Sauger and walleye

diet shih from mplankton to chironomids, Buefis, and Herogenia, and eventually to

fish (Carlander 1997).

Pike are highly piscivorous (Seaburg and Moyle 1964, Lawler 1965, Wolfert and

Miller 1978). Invertebrates, however, are part of the diet for large pike in some systems

(Lawler 1965, Wolfert and Miller 1978, Dick and Choudhury 1996)- Pike start to feed at

1 1 - 12 mm in length (Hunt and Carbine 1950) and cladoçera are the main food source

d l they reach 30 mm (Hunt and Carbine 1950, Frost 1954). From 30 mm to about 100

mm pike feed on aquatic insects and some fish and pike >100mm feed almost entirely on

fish (Hunt and Carbine 1950, Frost 1954, Bregazzi and Kennedy 1980).

Mooneye in the Assiniboine River feed entirely on insects with corixid beetles

occurring in 80% of the fish captured (Glenn 1975a). Mooneye showed no change in diet

with age (Glenn 1975a). Young of the year mooneye in the Assiniboine River ate

rnayflies, caddisflies, and chironomids until mid Juiy when they were large enough to eat

adult corixids (Glenn 1978). Stoneflies were the predominant food in fa11 and winter of

the first year (Glenn 1978).

White suckers feed primarily on chironomids and Hexagenia. Simulzum, and

Hydropsyche (Johnson 1977, Eder and Carlson 1977).

Pike and yeilow perch are visual feeders and tend to feed during the &y (Toner and

Lawier 1969, Jansen and MacKay 199S). Waileye are also visual feeders but their eyes are

well adapted to low light conditions and tend to feed during the night (Ryder and Kerr 1978).

The study of the diet of fish using stomach contents as a basis for analysis is quite

cornmon Several methods exist when studying stomach contents. Stomach contents of

fish are generaIly measured numerically, volumetrically, or gravimetrically (Hynes 1950,

Windell and Bowen 1978, and Hyslop 1980). Many indices exist to analyze the data once

it is grouped by prey category either based on abundance, volume, or weight. Morisita

(1 959)' Hom (1 966), Macarthur and Levins (1967), Levins (1968), Schoener (l970),

Pianka (I973), and Hurlbert (1978) have ail suggested an index of overlap either

specifically for food or more ofien for any resource. Pianka's and Hom's indices are

modifications of Morisita's index. Several authors have tested the abilities of some of the

indices (Hurlbert 1978, A b m s 1980, Wallace 1981, Linton et al 1981, Smith and Zaret

1982, Wallace and Ramsey 2983, Smith 1985, Krebs 1989). A major objection to the use

of overlap indices is the lack of prey availability information (Hurlbert 1978, f etraitis

1979, Wallace 198 1). Linton et a1 (1 98 1) tested Pianka's, Hom's, and Schoener's indices

with known overlap data and found only Schoener's index accurately measured overlap

between values of 7 - 85%. The method perfonned less well below 7% and above 85%

overlap. Wallace (198 1) recommended Schoener's index with resewations and Abram

(1980) suggested that Schoener's index was easy to use and not affécted by changes in the

nurnber of resource States (prey items). Schoener's index of diet overlap and Levin's index

of diet breadth were chosen to study the feeding d y n d c s of the fish species of Round

Lake keeping in mind the reservatioos of some authors and understanding the limits of

these methods,

The objectives of this study were to 1) detennine growth characteristics of the

major fish species relative to lake sturgeon. 2) determine food items consumed by fishes

in a pristine lakehiver system and to compare these results with what is cunently known

about lake sturgeon diet.

As the lake sturgeon population in Round Lake is so vuinerabie to any

exploitation no lake sturgeon samples were taken for food items. Consequently only

inferences cm be made- However, food items coiiected fiom lake sturgeon fiom a very

similar system, the Winnipeg River indicate that food consisted of Ephemeroptera,

Trichoptera, Diptera, Odomta, cnistacea, leeches, bivalves and fish (Table 2).

MATERIALS AND METHQDS

Field Sampüng

Standard gang giil nets (0.75, 1.5,2.25,3,3.75,4.5, and 5 inch mesh) were used

to sample the fish population of Round Lake. Fish caught in gill nets were weighed and

fork length was measured. Ttie whole fish or the viscera were then placed in labeled bags

and placed on ice. Al1 fish were used for age-length data and stomach content data.

Stomach Content Analysis

In the lab the stomach contents were removed and stored in 70% ethanol. Al1

stomach contents were identified to family where possible. Only stomach contents

identified to family were used in the analyses. Al1 fish remaius recovered nom the gut

were unidentifiable and therefore grouped together into one category. Three hundred and

six fish fkom 6 species; yellow perch (Perca flavescens), walleye (Stizostedion vitreum),

sauger (Stizostedion canadense), pike (Esox lucius), mooneye (Hiodon tergisus), and

shorthead redhorse (Moxostoma macrolepeditum), over three years were used for

analysis of stomach contents. Percent occurrence, percent total abundance, diet breadth,

and diet overlap were calculated using the following equations:

1) % occurrence

nj=SG/I: Sa,

where Sij is the number ofpredator i stomachs that contain prey j.

2) % total abundance

pi j=nG/LnS,

where nij is the total number of prey j items found in the stomachs of predator i.

3) Levins (1968) diet breadth index

B = [ P Pi2 ] -' where pi is the proportional contribution in number of individuals of prey 1 to the total

number of prey items, and S is the nurnber of prey.

4) Schoener's (1970) index of diet overlap

D=I -1 /2ZIpx , i -py7 i I

Where p, i and i are the fiequencies for species x and y, respectively, for the ith

category.

Multiple discriminant analysis was used to compare the diets of four fish species

from Round Lake: yellow perch, walleye, sauger, and rnooneye. Invertebrate famiiies

were grouped into five categories; benthic macroimrertebrates, benthic

microinvertebrates, surface beetks, Ephemeridae and fish. Fish were grouped by species.

The analysis was nui using Syntax, multiple descriminant analysis with spherized scores.

Fish Aging Methods

Percids

The percids were aged using the operculm. The operculum removed fiom d l

percids in the field was placed into an envelope and labeled with the fish ID number and

date of capture. In the lab the operculum was placed in hot water for a few minutes to

loosen attached scales and skin d e r wbîch it was nibbed clean and allowed to dry- The

cleaned dried operculum was dipped in oil, observed with a dissecting microscope and

growth rings were counted and rewrded.

White sucker, redhorse, mooneye

The pectoral fin was removed fiom the fish in the field and placed in a labeled

envelope. The dried fins were mounted in epoxy that was allowed to polymerize over

several days. A Buehler Isomet Low Speed Saw was used to section the fin The annuli

on the fin sections were counted usiog a dissecting microscope.

RESULTS

Growth of yellow perch and sauger in Round Lake (Figure 21a and 21c) is

comparable to populations presented earlier (figure 3a and 3c). Growth of walleye (Figure

21b) was lower than populations woss Canada (Figure 3b). Growth of mwneye, white

sucker and shorthead redhorse in Round Lake (Figure 22) was comparable to populations

presented =lier (Figure 4).

Yellow perch are the most fkquently caught fish in Round Lake followed by

mooneye and walleye (Figure 23). Lake sturgeon were less than 100/o of the total catch

(Figure 23). Sauger were the most frequently caught fish in both the Winnipeg River systems

(Figure 23). Lake shirgeon were close to 15% of the total catch in the Winnipeg River

(Figure 23).

Ephemeridae are the dominant prey item of all species and they occur in greater than

50% of dl stomachs (Table 9) and are over 35% of the total abundance (Table 9). Fish were

almost 90% of the total abundance in pike stomachs and greater than 50% of the total

abundance in sauger stomachs (Table 9)- Notonectidae were greater thaa 40% of the total

abundance in mwneye stomachs and not found in any 0th fish species (Table 9).

Chironomidae and gammaridae were the dominant prey items in the stomachs of Redhorse

and were uncornmon in other fish species (Table 9). Thiry-seven families of invertebrates

were found h m the fish species of Round Lake (Table 10).

Figure 2 1. Age - length of yellow perch, walleye, and sauger-

Figure 22. Age - length of mwneye, white sucker, and redhorse.

Fork a N Leyth A (cmJ 0)

0 0 0 0 0 0 0

Fork Length (cm) - r - * N h ) G ) O P

O u l O u l O 0 i O ~ O

Figure 23. The composition of fish species in Round Lake, Seven Sisters-Slave Falls, and Slave Falls-Pointe du Bois.

- ---

Round Lake 35 , 1

Seven Sisters-Slave Falls

Slave Falls-Pointe du Bois

Table 9. Abundance of prey items in the stomach contents of yellow perch, walleye, sauger, mooneye, pike, and redhorse and abundance and occurrence overall.

- - --

Prey Category Perch Wdeye Sauger Mooneye Pike Redhorse Abundance Occurrence

Hydropsychidae 1 -2 1 3 .O2 O 4.54 O 0.75 2.3 8 5-88

C hironomidae O 0.93 O 0.09 O 30.84 5 -62 1.96

Gammaridae 0.76 0.46 O O. 19 O 39.25 7.15 2.61

Notonectidae O O O 40.83 O O 14.11 6.54

Fis h O 21.1 1 58.82 0.09 88.89 O 4.57 29.74

Table 10. Al1 families of invertebrate prey found in the stomach contents of fish fiom Round Lake

Ephemeroptera Ephemendae Oligoneuridae Baetidae Heptageniidae SiphlonurÏdae Caenidae Ephernerellidae

Odonata Gomphidae Corduiiidae Macromiidae Lestidae Li bellulidae Coenag rinidae C hloroperiidae

P lecopte ra P teronarcidae Petlidae Perlodidae

Trichoptera Polymitarcidae Ptilddactylidae Pol yœntropodidae H ydropsychidae Leptocendae Brachyoentridae Philopotamidae

Coleoptera Dryopidae Elmidae Sialidae Gyrinidae Dysticidae

Diptera Curculionidae C hironomidae S im ul l idae Chaoboridae

Hemiptera Corixidae Notonectidae

Cnrstaœa Gammaridae Pel yca poda Gastropoda Cyzicidae Sisyi ridae Carnbaridae Oaphnidae Hydracari na

Levins (1968) diet breadth index indicates that suckers are a more generalist feeder

than the other species in Round Lake and pike are the most specialized feeders (Table 1 1).

Pemh, walleye, sauger and mooneye are aiI s W a r in diet breadth. The highest overlap of

diet occurs for perch and walleye at 0.72 and for sauger and pike at 0.7 (Table 11). The die6

of mooneye and pike and the shorthead redhorse and pike have the least overlap at 0.1 and

0.0 respectively.

Figure 24 shows the distribution of the four fish species almg the multiple

descriminant analysis axes. Mooneye are firrthest along the surface beetle and

microinvertebrate axes. Walîeye and sauger are -est dong the fish axis, sauger slightly

M e r than walleye. Perch are furthest almg the Ephemeridae and rnacroinvertebrate axes.

Tabie 11. Schoener's (1970) index of diet overlap and LeMn's (1968) index of diet breadth for Perch, walleye, sauger, mooneye, pike, and shorthead redhorse.

Perch Walleye Sauger Mooneye Pike Redhorse

Perch - 0.72 0.37 0.49 0.1 1 O. 17

Walle ye - 0.47 0.49 0.29 0.04

Sauger - 0.18 0.7 0.02

Mooneye - 0.0 1 0.03

Pike - O

Redhorse - Levin's Diet Breadth 2.7048 2.5277 2.3 12 2.706759 1 1.246 154 3 -4974 157

Figure 24. Multiple descriminant analysis of four species of fish from Round Lake. Large hollow circles represent the 95% confidence intervals around each species. Lines represent the avis for each prey category îisted at the end.

SURFACE BEETLES

Canonical Variate 1

DISCUSSION

The growth daîa for the six species of fish used in the stomach content analysis is

similar to growth fiom other systems. The growth of walleye was lower than the other

populations d e s c n i in the general introduction This may be due to the lack of forage fish

spies. Very few mianows were caught in the small mesh nets set in Round Lake. M y

emerald shiners and spottai1 shiners were caught and never in large numbers. in general

though we consider Round Lake îypical of the natural systems that stingeon inhabit

Sauger were the most Erequently caught fish in the Winnipeg River and perch were

the most kquently caught fish in Round Lake. Lake sturgeon were less than 10% of the total

catch in Round Lake and close to 15% in the Winnipeg. Insight into the quality of each

system can be obtained from the study of wmmunity structure- Clady (1978) stated that

communities in which sauger are weU established are more diverse than communities in

which perch are well established Sauger prefer large sbailow turbid rivers whereas perch

numbers decrease with increased turbidity (Scott and Crossmm 1973). Comparuig what we

understand to be the requirements or optimal conditions for lake shngeon with that of the

primary species of fish in a system can help determine habitat quality. The community

structure of the Winnipeg River has probably changed since the hydroelectric dams have

b e n installed. Sauger predominate in the system where they may not have previously. Lake

sturgeon numbers have declined under the same circurnstances. Perch predominate in the

undisturbed Round Lake system. Lake sturgeon and perch diet probably overlap as much as

any other pair cornparison An abundance of perch may suggest the potential for cornpetition

but may also suggest an excellent habitat for lake sturgeon if prey abundance is not limiting.

A diet overlap index was useà in this sOudy to compare the stomach contents of the

large fish species fiom Round Lake- The goal was not to determine cornpetition but rather to

determine general trends and relate these to information taken from the Literaîure. Managing

fish species, especiaily lake sturgeon, requins knowledge of d aspects of the Me bistory and

diet is an important especidy if food is shared with other fish species with a signincanf

biomass in a given system. Comments on diet overlap and competition are made keeping the

limitations of the methods in min&

The use of diet overlap indices is widely used but has been criticized in the Literaîure.

The existence of competition is difncult to determine. Competition can be defïned as the

negative affect which one organism has upon awther by consuming or controlhg access to

a resource that is limitecl in availabiiity (Keddy 1989). Abrarns (1980) stated that there can be

no competition without a shortage of a resource and that there may be competition with little

diet overlap due to changes in diet in the presence of competition. Competition cannot be

predicted using only diet overlap measures. Zaret and Rand (1971) and Mathw (1977)

reported the level of diet overiap considececi to be biologidy signifiant is 0.6. What is

'biological significance' when one is loolàog at diet overlap. Again, without knowing

availability of prey in time and space or cornpetitive abilities of predators we m o t over

estimate the power of overlap measures.

The shonhead redhorse had a higher diet breadîh than the other species and pike had

the lowest diet breadth. Pike were highly piscivorous and seldom fed on invertebrates.

Sauger were also highly piscivorous but bad a brader diet than pike and consumed more

invertebrates. Perch and walleye fed on a large nurnber of invertebrates but walleye ate fish

occasionally while perch did not. Mooneye were the oniy species to feed on corixidae d

notonectidae which are both k t l e s that swim on the d a c e of the water. Mooneye seem to

bave exploited a niche that the other species do not. Perch were the predomuiant fish species

in Round Lake and probably have the grPatest potential for overlap with lake sturgeon diets.

White suckers and redhorse dso were primarily benthic insectivores and rnay also bave a

high diet overlap.

Perch, redhorse suckers, white suckers, and mooneye fed exclusively at the secondary

consumer level. Walleye and sauger fed at both the secondary and tertîary trophic levels.

Pike feed aimost exclusively at the tertïary trophic Ievel. Using Root's (1967) classification

scheme, the fish species ofRound Lake d d potentiaily be grouped into four grulds: benthic

insectivore, benthic insectivore/surface insectivore, bentbic insectivore/piscivore, and

piscivores. Perch and suckers would fit into the benthic invertebrate guild Mooneye would

fit in the benthic hvertebratdsurface beetle guild Walleye and Suger would fit Ui the

benthic invertebrate/fish guild and pike would fit in the fish guild

Attempts were made to flush lake sturgeon stomachs but this proved diflicult as has

k e n reporteci previously by (Beamish et al 1998). As stated previously the lake mirgeon

population was far too Merable to sacrifice individuals for food habits. Lake sturgeon diet

was not analyzed but inferences cm be made based on the literature. Lake sturgeon are

generally benthic invertebrate feeders. Strictly based on diet they d d be grouped with

perch and suckers in this category- Clams and crayfish are two potential prey species that are

found in Round Lake but not exploited by any of the species siudied Lake sturgeon may

have a separate niche feeding on these larger prey species.

Beamish et ai (1998) cornpared the diet of lake sturgeon in the Mamgami and

Groundhog Rivers with that of walleye, suckers, lake whitefish, northem pike, and

burbot. They found the highest overlap to occur between lake sturgeon and lake whitefish

and burbot Ephemeroptera were highest for numerical importance and fiequency of

occurrence for lake sturgeon in the Mattagarni and Groundhog Rivers. Ephemeroptera,

primarily Ephemeridae, were highest for numerical abundance and fiequency of

occurrence in al1 Round Lake fish species (Table 10).

While our understanding of lake sturgeon interactions with other fish species is

incomplete we do know that there is overlap in f d items consurnecf with a nurnber of

fish species. ie: yellow perch walleye, mooneye, and suckers. We also know that there is

some spatial segregation of habitat (substrate, location, and maybe depth) during the

optimum growing period. So the degree of overlap in food consumod is very likely to

depend on the system. For example, feeding on Daphnia in Lake Wuuiebago is not

considered typical. On the other hand, systems like Round Lake are much more likely to

be typical of historical ecological interactions for lake snirgeon and the associated fish

species. The interactions that occur in Round Lake are of considerable importance as it is

probably the ody example of a relatively unperturbed system where we have extensive

data.

GENERAL SUMMARY

+ Round Lake is a small, isolated, relatively unperturbed system with a vuinerable but

self sustainhg lake sturgeon population if there is no M e r removal of fish of

reproducing age.

+ The Winnipeg River is a series of mature reservoirs with selfsustaining lake sturgeon

populations based on some recnutment. n ie Seven Sisters-Slave Falls section has a

large proportion of impounded waters and a smailer proportion of flow of the river.

The SIave Faus-Pointe du Bois section is essentially a "flowing reservoir" due to the

proximity of the two hydroelectric dams and limited storage capacity.

Distribution of lake sturgeon in the Seven Sisters-Slave Falls system was highly

correlated with changes in flow. Density was highest in flow of the river sections and

low to absent in sections with reduced flows. ie. fiom Seven Sisters to Otter Falls.

+ Growth of lake sturgeon was not statistically different between the three study sites.

Growth was statistically Merent between lake sturgeon populations presented in the

literature. Growth seemed to Vary based on the systems characteristics. Lake sturgeon

populations associated with large productive lakes had higher growth rates than river

populations regardiess of latitude.

+ Lake sturgeon in Round Lake spent significant amounts of t h e sw-mming in the

water column. More fiequent movements occurred in the vicinity of flows at the inlet

and outlet of Round Lake and along the contours of the nverbed throughout the lake.

Available substrate ranged fkom silt to boulder, with coarse sand, grave1 and pebble

being the most abundant. Lake sturgeon selected primarily fine sand substrates.

+ Growth of the major fish species in Round Lake was typical of that presented in other

systems. The fish species composition difEered slightly between Round Lake and the

two Winnipeg River sites. Sauger were predominant on the Winnipeg River whereas

yellow perch were in Round Lake. Lake shugeon were less than 10% of the total

catch in Round Lake and close to 15% in both Winnipeg River systems.

+ Ephemendae were 36% of the total abundauce and 52% occurrence in the stomach

contents of six species of fish fiom Round Lake (Percafluvescens, Stizostedion

vitreum. Stizostedion canadense. H i d o n tergisus. Esox lucius. Moxostoma

macrolepedinan). There is expected diet ovedap of lake sturgeoa and a number of

fish species in Round Lake. ie. yellow perch, walleye, mwneye, a d the shorthead

redhorse.

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Threatened and Endangered Animais

Phylum: CHORDATA Class: ACilNOPTERYGII Order: ACIPENSEFUFORM ES Family: ACIPENSERIDAE

J

Species: mser &a stenorrhynchus

i . . kr:8cdenstaedtrr

Species: m e r m e n - Black Sea stock

r uueldenstaedtii Caspian Sea stock spccies:k:=833

Species: Sea of Azov stock

A- Spuies: Bonaparte, 1836

Aral Sea stock

1 Speciies:

1 Species:~&&nser nu(üvent& Black Sea stock

AuDenw medi*stris Ayres, 1854

I

Species: m n s e r nudivent& Caspian Sea stock #

River Danube su bpopu lation

chus desotoi 1

Species: l

Species: r oxvrrncha ssp.

z7- Spccicr: A c i ~ s e r wmic(cz Black Sea stock

t

Species: mrsicus Caspian Sea stock

u0pnser nithena Spmim: h a e u s , 1758

r ruthenus Caspian and Black Sea drainage stock 4

mer ruthen= Rivers Irtysh, Ob and Yenisei subpopulation

Black Sea stock

wser s m Caspian Sea stock

1 ~ p e c i e s : r \ ~ ~ ~ " River Kootenai su bpopulation

Specicr: Sea of Azov stock

1 spacies:l Huso Adriatic Sea stock

( species:l Black Sea stock

Spccicr: Caspian Sea stock

Species: Huso Sea of Azov stock

Lake sturgeon age-bngth data for the study sites in figures 2 and 7. (NID)=no data

1 2 1 i 2824 NID I 1 35-58 1 3 1 NID 1 31 -54 4 f NR) t 34.57

5 1 NID 1 37.32 6 1 NID 1 39.61

NID 1 41 2 5 NID 5025

9 j 53.8 1 46.n 10 1 71 -5 i 49.52

42.02 49.33

NID 1 56 N/D 1 59.5

11 12

54.93 58.14

NID NID

13 1 78.4 14 1 82.8

19 1 95.9 i 64.1 9 i NID 1 OS i 89.96 20 ! 94 -6 66.94 66.02 1 100 91 2 4

68.5 1 67.49 73 73.45

58

15 1 89.9

54-38 f NID 1 82 52.82 1 NID ! 86

51.0s ] NID 1 7525

77.76 81 -06

58.69 1 NID

. - 29 1 1 17.8 1 86.2

74.83 78 1 51-06 1 NID 77.5

16 1 91 -3 1 57.59 NID

77.3

87.5

NID

NID NID

1 -

31 1 1 15.4 1 92.M 32 1 1 15.4 1 111.87

--

33 1 114 34 ! 1 15.8

137 ! - - p 125 1 103.62 NID NlD NID I

84.55 87

30 1 1122 1 83.45 1 77.03 1 NID

85.83

N/D 1 FUD

71.53 f NIQ

94.45 1 8024 1 NtD 91.7 86.2 1 NiD

NID NID

35 fp 1 20 1 101.79 1 87.67 1 NID

NID

72-44 NfD NID

36 1 125.5

38 1 108.5

NID

106.37 ! N/D 1 NID 1 NID

1 f NID 40 143 106.37 1 NR)

41 1 NID 109.12 [ NID Nlb 42 1 117 f 115.54 1 NID 1 NID

-- - - 1 49 1 1% 1 NfD 1 NID N/D 1 NID 1

99.95

39 1 130 t 02.7 ! NID NID NID N/D Nlb NID

NID 1 NID

75 1- NI0 110.04 U 45 46

N/D N/D NID N/D N/D N/D

47 48

105.46 1 NID NID N/D 15j.31 9829

NID N/D N/D

NID NID 1 NID 1

121 1 99.95

N/D 1 NID N/D NID NID NID

NID 125.63

APPENDIX 2: con?

Fortin et al1 993 ;eikorlffl Lam-LOUP (LscSt-Piefre[ MidJOrn

prisod 1973 MsriaminaeRivar

16 AGEf 13 - NID NID NID

14 1 15 1 2 3

pnsod 1973 L a k e W w

17 NID N/D NI0

Robsl+Coo9cr(l955)~ Schdl19û6 iakeW- Ifbmbaau M

18 t 19

4 5 6

NID NID NID

NID NID

45.21

I

NID 13.76 2522

7 1 N/D 8 1 73.73 9 1 82.16

NID 13.76 2522

N/D NID

27.51 36.68 43.56

28.66 36.91

69.4 75.42 101 81.43 1 74.55

N/D i 46.31

N/D 1 NID 25.22 36-66 52.73 59.61 71 .O7

111 86.2 1 73.73

882 1 50.66 1 48-14 ! 75.65

69.48

15.53 29.05 3ô.13

46 NID ! NlQ

52-85 I N/D

65-1 1 , 63.36

63-55 f NID

73.1 3 66-46

6214 56.62 63.04

100.87 --

Nlb

73.36

66.78 1 63.04

12 / 85.01 103-16 1 72.02 1 76.57

77.95

55.02 61 -9

79.05 i 79.78

82.53 9629

13 1 86.01 1 4 87.57

105.46 ôû.6 1 û4.82 1 8024 j 107.75 4 5 1 91.01 1 87.1 2 I 105.46

78.28 1 76.11 81 -91 79.32

74.64

83.1 2 76.34

76.1 1

15' 87.85 85.56 1 95.14 1 89.41 1 1 12.33 16 17

89.77 92.43

68.95 1 10225 1 9628 88.67 ] NID 1 93.99

, 92.89 ] 105.M / 105.46 18 [ 92.98

116.92 1 89.77 82.3

19 20 21

88.72 97.43 93.53

11921 123.8 123.8

93-44 96.29 94-1 8

93.63 96.65 94.63

24 25 26

96-45 101 .48 100.47

89.03 90.1

123.8 1 28 -38

116.92 1 89-77

22

105.66 1 105.46

10426 1 104.9 109.31 1 104.54 104.63 121.5

11921

97.39 j 95.92

105.91 112.1 112.33

922

23

107.75 1 12.33 1 12.33 102.28

27 1 118.38

9927

1 1 6 2 3 1 11921 1 126.09

118.1 1

116.69 121 .O4 121 27

100.87 f 103.16 106.32 1 03.39

112.33 98.94 1 103.62 102.89

1 16.92 132.97 121 -5 13526 i

116.92 1 139.84 108.33 1 14.79

115.31 9927

114.17 108.89

113.18 28 29

1 07.75 119.85 110.96 t15.8 1 121 -73

30

121 -5 137.55 123.8 1 139.W

Nlb 1 125.63

114-17 123.61

31 32

128.38 1 142.1 4 1 1 1 3.78 114.17 125.4

106.83 1 32.05 128.38 t 142.14 1 12225 1 116.46 127.83 126.m 124.94

129.39 NID 1 1 3 2 2 8 ( 135.26 146.72 124.47 I

142.1 4 1 1 26 .29 137.55 142.14

33 1 N/D I N/D 1 131.13 1 14.63 NID 34 1 136.91 i 131.31 NID

144.43 ! 12326

129.98

119.4

351 NID 1 N/D 138.4 135.26 142.14 1 125.89 135.03 138.01

130.67 13526

36 37 38 NID NID 140.53

149.01 f 131 -53 1 NID 151 -31 1 32.74 135.95

NID 1 NID

39 40

Ni0 137.55 1 1 49-01

11 8.02 138.7 131 -13 f 1 22.65

NID 133.35 1 NID

NID 1 NID NID 1 NID

N/D 411 NID ( N/D 132.51 42 f NID 1 NID 1 143.51

139.15 1 137.55 j 151.31

43' a 45 46

144.43 1 155R9 1 136.58

147.87 149.01

N/D 1 155.89

54 93 57

142.11 1 158.18 149.01 1 155.89

NID i N/D NID NID ( 148.49 NID 1 NID 1 142.14 N/D N/D NfD 1 N/D

I

132.51 151 -31 150.16 160.25 1 M.85

471 NID 48 1 NID

126.09 149.01 142.14 L 151 -31

NID N/D

NID 1 N/D NID N/D N/D 1 NID

NID NID N/D

141 22 1 NID Nm NID

49 j NID l Ni0 50 5 1 52 53

NID NID NID

NID NID N/D

14747 I NID

NID N/D NID NID NID

N/D NID N/D NID NID

151 39 1 74.23 161 -16 165.75 166.5 159.33 1 65.75

58 59 61 62 64

NID NID NID ! NID NID N/D

NID 1 NID 1 150.39 NID I N/D I171.94 NID 1 N/D 1 7 1 . 9 4

N/O N/D Nm NID NID N/D Nm

NfD NID NID Nlb N/D

NID NID

NID NID NID NID NID NID NID

139.84 1 165.06 1 NID N/D 1 NID NID NID f NID f NID NID NID NID N/D 1 NID 1 14525 N/D r NID NID

NID L N/D

NID NID

NID 140.99

NID 1 N/D N/D NID I Nm NID

Movements of lake sturgeon in Romd Lake in July and August 1997 using acoustic telemetry (Figure 4, Begout-Anras et al in press)

Fish no. 1

Fish no. 3

Fish no. 5

Fish no. 7

Fish no. 2

- --

Fish no 4

Fish no- 6 - 71 Fish no. 8

APPEmIX 4

Movernents of lake sturgeon in Round Lake in 1996, 1997, and 1998 using radio tags.

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