Abstracts:  Papers

 

 

Maternal Liver and Egg Thiamine Concentrations in Walleye from Lake Oahe, South Dakota

 

Michael E. Barnes1, Micheal H. Zehfus2, Clark Moen3, and Kelly S. Stock2

 

South Dakota Department of Game, Fish and Parks

1McNenny State Fish Hatchery, 19619 Trout Loop, Spearfish, South Dakota, 57783, 605-642-6920.

3Blue Dog Lake State Fish Hatchery, RR1 Box 22A, Waubay, South Dakota, 57273, 605-947-4657.

2Black Hills State University, 1200University, Spearfish, South Dakota, 57799, 605-642-6028.

 

Thiamine analysis in all its forms (thiamine pyrophosphate = TPP, thiamine monophosphate = TMP, free thiamine = FTH, total thiamine = TPP+TMP+FTH) was conducted on maternal liver tissue and egg samples from walleye Stizostedion vitreum spawned at three locations on Lake Oahe, South Dakota in April 2000.  Reproductive characteristics of these fish and survival of their progeny during hatchery rearing were also recorded.  Liver TPP, TMP and total thiamine differed significantly between all three spawning sites, and increased with increasing distance from Oahe Dam [Cheyenne arm (CA) < Moreau River (MR) < Grand River (GR)].  Liver FTH was significantly different between CA and GR, but not between MR and either CA or GR.  Mean total thiamine was significantly less from eggs collected at MR (1.54 nmol/g) compared to GR (2.65 nmol/g) or CA (2.60 nmol/g).  Egg TPP followed a similar pattern. Embryo survival to hatch was extremely variable, but was significantly different only between MR (68.0%) and GR (32.7%) eggs. Maternal length and weight were significantly correlated with egg TPP and FTH.  Maternal length and egg TPP were also significantly correlated with the total number of eggs per female.  Survival to hatch was only correlated with egg size.  The increases in liver thiamine with increased distance from Oahe dam are attributed to differences in adult walleye consumption of thiaminase‑containing rainbow smelt Osmerus mordax between the spawning locations.  Reproductive performance data was likely influenced by severe dietary stress and may be atypical.  

 

 

 

Sunnies-More Than Fish for Kids and Sissies

 

Daryl Bauer and Donald W. Gabelhouse, Jr.

 

Daryl Bauer, Nebraska Game and Parks Commission, Fisheries Division, 2200 N. 33rd Street, Box 30370, Lincoln, NE 68503, (402) 471-5005, dbauer@ngpc.state.ne.us.

Donald W. Gabelhouse, Jr., Nebraska Game and Parks Commission, Fisheries Division, 2200 North 33rd Street, Box 30370, Lincoln, NE 68503; (402) 471-5515, dgabel@ngpc.state.ne.us.

 

While Lepomis sunfish are exceeded in popularity by “glamour” species in all North Central Division, American Fisheries Society (NCD) states except Indiana, they are sought by 43, 61, 70, 72 and 84% of all anglers in Nebraska, Iowa, Wisconsin, Illinois and Indiana, respectively, according to Centrarchid Technical Committee representatives.  Bluegills (Lepomis macrochirus) dominate the angler catch and harvest of Lepomis sunfish; the highest average annual harvests of Lepomis sunfish among NCD states occur in Nebraska (76 fish per acre) and Kansas (21 pounds per acre).   Bluegill >8 inches and redear sunfish >9 inches occur in approximately one-quarter of all water bodies in NCD states that contain these species, but <3% of all water bodies containing green sunfish (Lepomis cyanellus) and pumpkinseed sunfish (Lepomis gibbosus) produce fish >8 inches.  High predator densities, abundant food supply, optimal aquatic vegetation, a lack of competitive species and low fishing pressure are factors considered most important for producing preferred-length Lepomis sunfish.  From 1985 through 2000,  Nebraska and Illinois produced more In-Fisherman magazine awards for Master Angler (>1.5 pounds or >11 inches) bluegills than any other state or province in North America.

 

 

Walleye Length Limits in Nebraska

 

Daryl Bauer, Nebraska Game and Parks Commission, Fisheries Division, 2200 N. 33rd, Lincoln, NE 68503, (402) 471-5005, dbauer@ngpc.state.ne.us

 

Minimum length limits on walleye (Stizostedion vitreum) have a long history in Nebraska.  Prior to 1990, state-wide minimum length limits of 12 inches and 15 inches were implemented mostly for social reasons.  No evaluations of the impact these regulations had on walleye populations were ever made.  In 1991 the Nebraska Game and Parks Commission Fisheries staff held a series of public meetings concerning fishing regulations--primarily walleye length limits.  These meetings resulted in minimum length limits being implemented on nine reservoirs in 1992 and on six more in 1993.  On reservoirs with slower-growing walleyes, a 15-inch minimum length limit was imposed, while 18-inch minimum length limits were implemented on reservoirs with faster-growing walleyes.  In addition, a daily bag limit of one walleye longer than 25 inches was placed initially on three reservoirs to protect brood stock for egg collections for hatchery needs.  Later, this restriction was expanded to include two more reservoirs.   After 10 years, evaluations have shown that the 15-inch minimum length limits have had limited impacts on walleye populations in most reservoirs with that regulation.  The 18-inch minimum length limits have been more successful in increasing angler catch rates and providing larger fish for anglers to catch.  The bag limit of one walleye longer than 25 inches has done little to protect large walleyes.   Future walleye regulations will be implemented according to public input and management objectives for each reservoir.

 

 

Application of Aquatic Gap Analysis to Conserve the Endangered Topeka Shiner

 

Charles Berry, USGS, South Dakota Coop Research Unit, and Steven Wall and John Jenks, Department of Wildlife and Fisheries Science, South Dakota State University, Brookings.

 

The Topeka shiner (Notropis topeka) is found in streams in six Great Plains states including South Dakota.  An estimated 80% reduction in the occurrence of Topeka shiners caused it to be listed as endangered, but distribution information was lacking for South Dakota.  The goal of our study was to determine the distribution of the shiner and use Aquatic Gap Analysis procedures to suggest conservation measures.  Our study area was the James, Vermillion, and Big Sioux River basins.  GIS was used to delineate types of valley segments based on eight habitat variables; stream size, flow regime, gradient, ground water potential, surface geology, size discrepancy, floodplain interaction and connectivity to a lake.  The habitat attributes of valley segments with Topeka shiners were used to classify other valley segments as having high, moderate, or low potential for presence of the shiner.  The location of conservation areas such as Federal and State lands, and easements and leases on private land were matched to the known and predicted Topeka stream reaches.  Gap analysis showed that watersheds in the James River Basin had the most protected status.  Two watersheds with Topeka shiners present in the Vermillion River Basin and eight in the Big Sioux Basin had no lands in protected status (1994 data).  Our model is useful to federal and state agencies for defining critical habitat, bringing new land under conservation agreements, searching for other Topeka shiner populations, assessing the probable impact of planned developments, and stream and watershed habitat restoration.

 

Honest, Officer - My Walleyes Shrunk!

 

Brian G. Blackwell, Matthew J. Hubers, and Robert G. Losco

South Dakota Game, Fish and Parks, Webster, SD  57274, (605) 345-3381

 

Information concerning post-harvest changes in fish length is important in the enforcement of length-based regulations.  We evaluated whether walleye Stizostedion vitreum lengths changed following angler harvest and after being frozen.  Walleyes were collected by angling during open-water periods at various water temperatures and during ice cover.  To simulate angler practices, post-harvest walleyes were placed in a cooler containing ice or a livewell.  Post-harvest, open-water collected walleyes were measured at 1-h intervals through 10 h, at 20 h, and after 30 days of frozen storage. Walleyes collected during ice fishing were measured through 29 h, at 44 h, and after 30 days of frozen storage.  All collected walleyes were frozen for 30 days, because 30 days is often the time period that walleyes are held before being introduced as evidence in court.  Post-harvest walleyes held in a cooler tended to lose length with the greatest decrease occurring from walleyes collected at the coldest water temperatures.  A two-way ANOVA indicated that both water temperature and time were significant (P < 0.05) influences on length change for open-water caught walleyes stored in coolers.  Length change was minimal for walleyes held in livewells.  Measurement time was not significant, but water temperature significantly influenced length change of walleyes held in a livewell.  Length change for walleyes caught through the ice was similar to the change observed for cooler-held walleyes caught at the coldest open-water temperature (10 oC), but the amount of time for change to occur was longer.  All walleyes held in frozen storage exhibited a decrease in length from capture.

 

 

 

Reetz Lake – A Different Approach

 

Brian G. Blackwell, Matthew J. Hubers, Todd M. Kaufman, and Ryan J. Braun

South Dakota Game, Fish and Parks, Webster, SD  57274, (605) 345-3381

 

South Dakota panfish regulations generally have followed a liberal daily limit.  In northeastern South Dakota, a daily limit of 25 yellow perch Perca flavescens has allowed for overexploitation of quality-length individuals in several new waters -- often characterized as “boom and bust.”   Reetz Lake (243 ha), South Dakota contained an unexploited fish community and has provided the South Dakota Department of Game, Fish and Parks with an opportunity to try a different management approach.  In an attempt to maintain yellow perch size structure [proportional stock density (PSD) = 50 to 80] and abundance of large perch we placed restrictive regulations on Reetz Lake before the lake opened to fishing on October 2, 2001.  The regulations include a daily limit of five yellow perch of which only one can exceed 25 cm (10 in) and the walleye Stizostedion vitreum daily limit is one with a minimum length of 71 cm (28 in).   During spring 2001, we estimated the adult yellow perch population at 113,866 individuals and adult walleyes at 697 using mark-recapture Schnabel estimates from trap-net catches.  The PSD for the yellow perch trap net sample was 78 and relative stock density of preferred-length fish (RSD-P) was 40; the walleye trap net sample PSD was 100 and RSD-P was 70.  Yellow perch population modeling indicated that at an angler exploitation rate of 30% the abundance of 25-cm perch would decrease by 33%, abundance of 30-cm perch would decrease by 62%, and the abundance of 36-cm perch would decrease by 89%.  Angler acceptance of the regulations and satisfaction currently are high.

 


Comparative Acute Toxicity of Fire Control Chemicals to Fish and Aquatic Invertebrates

 

Buhl, K.J., Hamilton, S.J., McDonald, S.F., Gaikowski, M.P., U.S. Geological Survey, CERC-Field Research Station, 31247 436th Avenue, Yankton, SD  57078, Tel.  605-665-9217, FAX  605-665-9335, email: kevin_buhl@usgs.gov. 

 

Fire-retardant and foam-suppressant chemicals are used extensively in North America and are often applied in environmentally sensitive areas that may contain endangered or economically important animal species.  Prior to our research, little published toxicity information was available on these chemicals.  We conducted a series of acute toxicity tests with three commonly used fire retardants (Fire-Trol LCG-R, Fire-Trol GTS-R, and Phos-Chek D-75-F) and two foam suppressants (Phos-Chek WD-881 and Silv-Ex) in hard and soft water.  The organisms tested were chinook salmon, fathead minnow, rainbow trout, and two aquatic invertebrates (Daphnia magna and Hyalella azteca).  The two foams were substantially more toxic to all species than the three fire retardants. For the foams, Phos-Chek WD881 was as toxic or more toxic than Silv-Ex.  Among the fire retardants, Fire-Trol GTS-R and Phos-Chek D75-F were more toxic than Fire-Trol LCG-R, except to H. azteca.  Water quality had a significant, but contrasting effect on the sensitivity of H. azteca and fathead minnow to the fire retardants; H. azteca were more sensitive in soft water and fathead minnow were more sensitive in hard water.  Overall, H. azteca was the most sensitive species to the fire retardants in soft water, fathead minnow was the most sensitive species to the fire retardants in hard water, and D. magna was the most sensitive species to the foams in both water types.  Comparison of toxicity data with application concentrations indicates that accidental inputs of these chemicals into aquatic habitats require large dilutions to the reach non-toxic concentrations.

 

 

 

Effect of Phenotypic Plasticity on Vulnerability to Predation: A Multi-adaptive Polymorphism in Juvenile Bluegill Sunfish

 

Steven R. Chipps, USGS South Dakota Cooperative Fish and Wildlife Research Unit, Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, SD, 57007; ph 605-688-5467; email steve_chipps@sdstate.edu.

and

Jessica A. Porter and David H. Wahl, Kaskaskia Biological Station, Center for Aquatic Ecology, Illinois Natural History Survey, RR 1 Box 157, Sullivan, IL, 61951

 

Ecologists have long recognized that polymorphism is a common occurrence in nature.  The observation that many organisms exhibit two or more distinct forms, provides a unique opportunity to study interactions among environmental factors, ontogenetic development, and selective mechanisms that regulate phenotypic expression.  In effect, these ‘alternative adaptations’ allow a single population to occupy more than one sympatric niche and have important implications for evolutionary ecology.  In bluegill sunfish, habitat-linked polymorphism has been well documented.  Bluegills inhabiting dense vegetation have more laterally compressed bodies and longer fins than bluegills collected from open water lakes and ponds.  Previous studies have shown that these morphological differences affect foraging efficiency in different habitats.  In this study, we show that polymorphism also effects vulnerability to predation.  The observation that two distinct morphs exhibit traits adaptive for both foraging efficiency and predator avoidance supports the adaptive plasticity hypothesis – which is the notion that phenotypic plasticity evolves as a mechanism for adaptation to spatially or temporally variable environments.

 

 

Nebraska and South Dakota 2000 Missouri River Recreational Use Survey

 

Steve Freeling, Gerald Wickstrom, Gerald Mestl, and Cliff Stone, Organization:  South Dakota Department of Game, Fish and Parks, Nebraska Game and Parks Commission

 

The 2000 Missouri River recreational use survey ran April 1 through December 31, 2000 and surveyed the Ft. Randall Dam to Big Sioux River mouth reach.  User data were collected through postage paid post cards left on vehicles, and through personal interviews.  Pressure data were collected from ground counts of vehicles, boat trailers, and recreational users.  Recreational users spent an estimated 745,303 hours on the Missouri River survey reach during 2000.  Fishing accounted for 62% of all recreational use and recreational boating accounted for 34% of all use.  Hunting, camping, picnicking, sightseeing, observing wildlife, outdoor photography, and other uses accounted for only about 4% of the total use.  Recreational anglers caught an estimated 455,988 fish, and harvested an estimated 159,420 fish from the survey reach during 2000.  Walleye was the single most harvested species at an estimated 29,676 fish, and supported a catch rate (harvest rate and release rate combined) of 0.22 fish/hour.  Freshwater drum was the second most harvested species at an estimated 20,638 fish, with a catch rate of 0.10 fish/hour.  Catfish (channel, blue, flathead, and bullheads) was the most abundant species group in the creel at an estimated 36,500 fish, with a catch rate of 0.21 fish/hour.  Anglers from 29 states were contracted during the survey, with approximately 88% of them being from either Nebraska or South Dakota.  Walleye was preferred by approximately 45% of the anglers fishing the survey reach, followed by catfish at 21%.  Over 60% of the anglers expressed some degree of satisfaction with their angling experience.  

 

 

 

 

Genetic Analysis of a Monsex Population of Walleye

 

Tate Glader and Shane K. Sarver, Department of Biology, Black Hills State University, 1200 University Avenue, Spearfish, SD 57783, 605-642-6043

 

In 1996, using eggs collected from two spawning stations at Lake Oahe, 800,000 walleye fry were planted into Park’s Pond in northeastern South Dakota. Beginning in1999 this population was used as a source of eggs for hatchery propagation and stocking the resulting walleye fry at various locations in South Dakota.  This population was an excellent source of eggs because of a striking predominance of females. In 1999, all fish sampled were females.  Males from Lake Oahe were used as a source of sperm to fertilize the Park’s Pond females.  This unusual sex ratio was also noted in 2000 and 2001.  Given the sex ratio bias of walleye in Park’s Pond, there is concern about using this population as a source of eggs for the walleye propagation program in South Dakota.  Is the Park’s Pond population genetically distinct from Lake Oahe?  What are the implications of using Park’s Pond as broodstock?  And finally, what is the biological basis of the sex ratio bias?  We will use DNA sequence analysis of the mitochondrial d-loop region and microsatellite markers to compare Park’s Pond walleye with 3 samples from Lake Oahe.

 

 


 

Aquatic GAP Analysis for the Missouri River: What’s it all about?

 

Brandon Harland, Steven Wall, and Chad Kopplin, Department of Wildlife and Fisheries Sciences, South Dakota State University

 

Aquatic Gap Analysis is a US Geological Survey program to develop GIS data for states to use in planning fish conservation.  Terrestrial Gap Analysis projects are underway in most states, but Aquatic Gap Analysis is just beginning as a pilot study in the Missouri River basin.  Our Upper Missouri River Project is a companion to one for the Lower Basin being done by others.  The Upper Basin is upstream from Sioux City in six states (including North and South Dakota) and two Canadian provinces (Alberta, Saskatchewan).  Objectives are: 1) define the range for all fish species and species richness by 11-digit hydrologic units, 2) define habitat affinities of each fish species based on literature and our own field work, 3) predict occurrence of each species in river reaches by similarity of stream properties to habitat affinities, and 4) determine protection offered each fish species using GIS stewardship layers.  Using ArcView and other mapping software, river reaches will be described by temperature, stream size, geology, ground water potential, relative gradient, size discrepancy, and floodplain reach.  Based on fish collection data and state records, river reaches where species occur will be considered suitable habitat.  Fish distribution will be predicted for other reaches with similar stream properties.  Land use, land cover and the presence of dams also will be used to predict fish occurrences.  Sampling in selected streams to determine species occurrence will assess accuracy of these predictions.  Each species distribution will be analyzed for “gaps” in protection.

 

 

 

Nebraska Bluegill Population Characteristics

 

Keith Hurley, Nebraska Game and Parks Commission, Fisheries Division, 2200 N. 33rd Street, Lincoln, NE 68503, (402) 471-7653, khurley@ngpc.state.ne.us

 

The Fisheries Division of the Nebraska Game and Parks Commission implemented a statewide-standardized sampling protocol in 1994.  Bluegill populations were surveyed under this protocol with 5/8-inch bar mesh, double-throat trapnets set overnight in the spring.  Three hundred and fifteen bluegill surveys have been conducted of 130 bluegill populations from 1994 to 2000. Grand population means of catch-per-unit-effort (CPUE) of stock-length fish, proportional stock density (PSD), relative-stock density of preferred length fish (RSD-P), relative weight (Wr) of stock-length fish, and back-calculated length-at-age 3 (LAA-3) values were calculated for each population across years.  These grand population means were then compared across a simple lake classiffication system to determine if bluegill population indices were limited by waterbody type and to give state fisheries biologists the information necessary to determine appropiate and achievable management goals. All indices exhibited significant differences among waterbodies types indicating that average statewide values are not always appropate for management objectives, and in some cases may not be achievable.  Nebraska ponds exhibited the highest CPUE of all types with 86.5 bluegill per net night.  Nebraska irrigation reservoirs had the lowest mean CPUE at 7.0 fish per net night and never surpassed a CPUE of 27.7.  The world-class bluegill fisheries in the sandhill lakes of Nebraska had not only the highest RSD-p values of all waterbody types, but also the highest mean Wr and LAA-3 values (118 and 143, respectively).

 

 


 

Yellow Perch in Eastern South Dakota Glacial Lakes: Larval and Adult Dynamics, Exploitation, and Angler Attitudes

 

Daniel A. Isermann* and David W. Willis, Department of Wildlife and Fisheries Sciences, Box 2140B, South Dakota State University, Brookings, SD 57007, disermann@hotmail.com

 

 

We assessed larval yellow perch Perca flavescens dynamics, angler exploitation, and angler attitudes as part of a project designed to formulate management strategies for perch populations in eastern South Dakota’s lakes. Larval perch densities differed markedly between years in a few lakes, while in other systems differences in larval densities were less dramatic or non-existent. Larval density did provide a reasonable predictor of juvenile perch abundance in August seine hauls. Analysis of otolith microstructure revealed that the majority of perch larvae hatched during early May of each year, which corresponded well to the initial appearance of larvae in surface trawls. Preliminary results indicate that mean daily growth of larval yellow perch was 0.54 mm/day (SD = 0.10).  Based on summer gillnet sampling, inconsistent perch recruitment appeared conducive to production of preferred-sized fish, while in systems where recruitment is stable growth was slow and few fish over 254 mm were encountered. Estimates from two lakes indicate that natural mortality of yellow perch may be high (> 40%), which may preclude the use of size and creel regulations in managing perch fisheries. Exploitation of yellow perch in East 81 Slough was low during the winter of 2000-2001 (8%) and current exploitation of perch in Lake Pelican is less than 10%. Conversely, despite the fact that only 30 fish were tagged, exploitation of perch in Maynard’s Slough during 2001-2002 is currently 17%. Anglers support recently implemented creel reductions and would accept reductions in harvest if the size of the perch they caught was improved.

 

 

 

Using Geographic Information Systems (GIS) to Assess the Accuracy of Radio-Triangulation Techniques for Fish Telemetry

 

Daniel A. James1, Jack W. Erickson2, and Bruce A. Barton1

 

1Department of Biology, University of South Dakota, Vermillion, SD 57069 and

2South Dakota Game, Fish, and Parks, Rapid City, SD 57702

 

Accuracy tests were conducted for several triangulation methods that produce quantified rather than inferred transmitter-position data describing fish distribution.  Other telemetry studies have reported accuracies from 0.5 to 4 m based on visual observation of fish or detection of hidden transmitters from within streams.  In some studies, the methods used to determine accuracy were not reported.  With our geographical information system (GIS) method, coordinate locations for each transmitter position were recorded without entering the water.  A global positioning system (GPS) was used to record coordinate locations on the bank of a stream along with compass bearings to hidden transmitter signals.  The data were transferred to a database and triangulated, which gave estimated transmitter location coordinates.  The location coordinates were placed onto a GIS coverage and accuracy was determined by comparing actual positions to estimated positions.  This GIS method is less biased, supported by data, and could provide a standard for triangulation methodology.  Different triangulation methods resulted in slightly different accuracy levels.  This testing provided a higher level of reliability than visually based methods.  This GIS-based radio-triangulation approach will allow for tracking in the field without disturbing a tagged fish in its habitat or otherwise altering a fish’s behavior due to human intervention.

 

 

 

Fish and Habitat Relations to Local Variables and Watershed Size in the Big Sioux River, SD

 

Craig L. Milewski*, Department of Wildlife and Fisheries Sciences, Box 2140B, South Dakota State University, Brookings, SD USA 57007; (605-688-6611); edwdd2@brookings.net, and

Charles Berry, U.S. Geological Survey, Box 2140B, South Dakota State University, Brookings, SD USA 57007; (605-688-6121); berryc@mg.sdstate.edu

 

In eastern South Dakota, relations of fish and physical habitat to riparian condition, channel and bankfull dimensions, bank stability, and substrate are unclear.  Understanding these relationships among watersheds of various sizes would improve interpretation of stream assessments and define protection and restoration needs.  Our objective was to quantify relations of fish and physical habitat to local physical variables.  Local physical variables were measured using a transect method.  Fish population estimates in tributaries and fish relative abundance data in the river were used to quantify community attributes.  Relations among physical habitat variables were explored with principal components analysis and scatterplots.  Relations of fish populations and community attributes with physical habitat were analyzed with correlation analysis.  Our results show that tributaries displayed a large amount of physical variability among watershed sizes, while the river sites displayed distinct physical changes with watershed size.  Fish population estimates and fish community attributes were poorly correlated with physical habitat.  Our findings indicate that fish and physical habitat depend upon more than local variables and immediate land use.  Future research should focus on the effects of natural and altered watershed level processes on local fish and physical habitat conditions before protection and restoration strategies can be defined.

 

 

 

Application of River Concepts to a Semi-Arid and a Sub-humid River in South Dakota

 

Craig L. Milewski*, Department of Wildlife and Fisheries Sciences, Box 2140B, South Dakota State University, Brookings, SD USA 57007; (605-688-6611); edwdd2@brookings.net, and

Charles Berry, U.S. Geological Survey, Box 2140B, South Dakota State University, Brookings, SD USA 57007; (605-688-6121); berryc@mg.sdstate.edu

 

We tested the application of river concepts to South Dakota to define a large-scale framework for interpreting survey data in prairie streams.  We compared longitudinal patterns in channel and bankfull dimensions, streambank and riparian traits, substrate, and fish communities with watershed size between the semi-arid Bad River and the sub-humid Big Sioux River using analysis of covariance.  Physical patterns were explored with principal components analysis.  In the Big Sioux River, bankfull dimensions, channel bottom width, sand, and streambank deposition increased with watershed size, while silt, and percent vegetated bank decreased.  In the Bad River, most physical variables showed a random pattern or no change.  In the Big Sioux River, higher species richness, and the presence of intolerant/sensitive and headwater species contrasted with lower species richness, and the absence of intolerant/sensitive and headwater species in the Bad River.  This finding fits theory related to streamflow patterns.  The presence of pioneering species in both rivers, but the lack of the headwater species in the semi-arid Bad River suggests a subtle, biological analog to the physical environment.  More comparisons of prairie rivers with similar geology and climate are needed to facilitate understanding of subtle differences in systemic controls on physical processes and biology.

 

 


 

EMAP:  What is going on in Dakota streams?

 

Nathan Morey, Department of Wildlife and Fisheries Science, SDSU, Box 2140B, Brookings, SD 57007-1696, Phone:  (605) 688-4787 and

Charles R. Berry Jr. South Dakota Cooperative Fish and Wildlife Research Unit,SDSU, Box 2140B, Brookings, SD 57007-1696, Phone:  (605) 688-6121

 

The purpose of our presentation is to discuss the history of the environmental monitoring and assessment program (EMAP), review some findings from other parts of the country, and describe the Western Pilot Study (EMAP-WP) for streams.  The EMAP program focuses on evaluating ecological conditions on regional and national scales.  The need for the program was defined in the 1980s, when the Environmental Protection Agency needed data to evaluate the benefits of the Clean Water Act and the $541 billion spent on water pollution control since 1972.  Much water quality data existed, but the EPA had little data on ecological indicators, which have emerged as major water-quality issues.  In response, EMAP began in 1989 to establish a statistically sound national survey for monitoring ecological resources.  The goal is “to estimate and extend information on the current status and geographic distribution of ecological resources: the proportion of these resources that is degraded; trends in the conditions of these resources; and the probable causes of adverse effects.”  Biological response indicators are EMAP’s primary measure of ecological condition, but other chemical and physical indicators are being used to measure stress and chemical exposure of ecological resources.  In western streams the diversity of landscapes, stream sizes, and fish assemblages requires a “Western Pilot Study”.  Surveys of randomly selected stream reaches are conducted for water chemistry, physical habitat, periphyton, macroinvertebrate, and fish assemblages, and fish tissue. Currently the ND Department of Health and USGS-Biological Resources Division are in the second year of a three-year period of data collection.  Results of the Mid-Atlantic Highland Assessment Project will be presented as examples of the kinds of output expected upon the completion of EMAP-WP.

 

 

 

Larval Drift and Reproductive Strategies of Carp in the Red River of the North

 

Tim Resseguie and Steve Kelsch; The University of North Dakota, box 9019 Grand Forks, ND 58203; 701 777-2621

 

Photoperiod and water temperature clearly play important roles in initiating reproduction in fishes particularly maturation of gonads, migration and for many species triggering the release of gametes.  In floodplain river ecosystems, current velocity, discharge, and a rise water level may also be important factors triggering spawning behavior in fish adapted to these ecosystems. Common Carp (Cyprinus carpio) are one of the more abundant aquatic inhabitants of the Red River drainage.  They require submerged vegetation for spawning substrate that is normally only available when water inundates terrestrial vegetation on the floodplain.  We test the hypothesis that sufficient increase in discharge will trigger carp to spawn if photoperiod and temperature are with in the preferred range.  By collecting carp larvae using drift nets and back-calculating spawn dates, we were able to determine peak spawning times and relate these to the environmental conditions in the Red River and the confluence of major North Dakota tributaries. Carp spawned roughly 4 weeks later in 2000 when basin-wide discharge peaked in late June than in 1999 when discharge peaked in April. The timing of carp reproduction appeared to be highly influenced by increasing discharge. 

 

 

 

Fisheries Genetics Research at Black Hills State University

 

Shane K. Sarver, Department of Biology, Black Hills State University, 1200 University Avenue, Spearfish, SD 57783, 605-642-6043

 

This paper will review the ongoing fisheries genetics research program at Black Hills State University.  Past research includes research with economically important marine species, including snappers (Family Lutjanidae) and spiny lobsters (Genus Panulirus). Present projects focus on freshwater fish found in South Dakota and surrounding states.  Work is currently being conducted on walleye, Topeka shiner and finescale dace.  This work will be reviewed and future research priorities will be discussed.

 

 

 

Use of Formalin Treatments During Incubation of Eyed Eggs of Brown Trout

 

William Sayler, Assistant Hatchery Manager, McNenny State Fish Hatchery, Phone: 605-642-6920, e-mail: Will.Sayler@state.sd.us and

Michael E. Barnes and Rick J. Cordes, South Dakota Department of Game, Fish and Parks, McNenny State Fish Hatchery, 19613 Trout Loop, Spearfish, SD,  57783-8905, USA

 

To test the efficacy of formalin in controlling the fungus Saprolegnia, we administered daily formalin treatments (1,667 mg/L for 15 min) to embryos (eyed eggs to hatch) of brown trout Salmo Trutta and compared their survival with that of untreated embryos.  The study was conducted each year from 1996 to 1998.  In all 3 years, embryo survival to hatch in both groups was greater than 90%.  Survival to hatch was not significantly improved in the treated trays of eggs compared with the untreated trays, where dead eggs were manually removed for Saprolegnia control.  Both formalin treatments and hand-picking of dead eggs adequately controlled visible fungal development.  Although not essential for fungal control, formalin treatments on high-quality brown trout eggs from the eyed stage of embryo development through hatch are recommended to provide reduction in hatchery labor, but only if they can be administered safely.

 

 

 

Walleye Tagging and Creel Survey Lake Astabula, ND

 

Lynn R Schlueter, North Dakota Game and Fish Department, 7928 45th Street NE, Devils Lake, ND 58301-8501, phone 701-662-3617

 

A walleye tagging project and angler survey/creel was conducted at Lake Ashtabula, a 2,198 ha reservoir near Valley City, North Dakota.  The Barnes County Wildlife Club offered a reward to encourage tag returns.  The creel was done in the summer of 1999 and winter of 1999/2000 and found: 143,362 hours of angler effort, 0.03 walleye harvested per hour, 95% reporting of tagged walleye and 1% harvest of sublegal walleye.   Adult walleye were tagged with dangler tags in the spring; 360 in 1998, 209 in 1999 and 531 in 2000.  Only 355 mm or longer fish were tagged which is the reservoir’s minimum length limit.  Tagged walleye ranged from 350 to 760 mm with a mean of 470 mm.  A population estimate from annual sampling data found 15,750 walleye or 7.2 fish per ha or 7.0 kg/ha and was similar to MEI prediction.    Annual exploitation was 24% with most of the harvest occurring in July, May, June and October, ranked in descending order.  The catch of spawner walleye in April was 4%.   Four percent of the tag returns came from below the dam.  Ashtabula Crossing and Sibley Crossing accounted for 55% to the tag returns.  Thirty-six percent of the tag returns came from anglers living in Valley City, North Dakota. 

 

 

 

Condition and Structure of Shovelnose Sturgeon (Scaphirhynchus platorynchus) in the Lower Platte River, Nebraska

 

Dane A. Shuman, School of Natural Resource Sciences, University of Nebraska-Lincoln, 201 Natural Resources Hall, Lincoln, NE  68583, (402) 472-0825, daneshuman@hotmail.com and

Edward J. Peters, School of Natural Resource Sciences, University of Nebraska-Lincoln, 12 Plant Industry, Lincoln, NE 68583, (402) 472-6824, epeters1@unl.edu

 

The objectives of this research are to evaluate the condition, abundance, and size structure of shovelnose sturgeon (Scaphirhynchus platorynchus) in the lower Platte River, Nebraska.  Sites were located along the lower 46 km of the Platte River with the upstream site near the Elkhorn River confluence (1), the middle site near Louisville (2), and the downstream site near Plattsmouth (3).  Sturgeon were sampled using drifted gill nets, trot lines, and benthic trawls from May through August 2000 and 2001.  Length, weight, and abundance were compared among locations and between years.  The average relative weight (Wr) value of 334 sturgeon was 86.61, indicating a fit population.  Site 2 had significantly higher Wr values than sites 1 and 3 (p= 0.025: sites1,2; p= 0.007: sites 2,3), which were not significantly different (p= 1.00).  Mean catch per 100 m drift for gill nets was 0.76 for all sites and ranged from 0.42 at site 1 to 0.99 at site 3 indicating greater fish densities near the mouth of the Platte River.  CPUE was significantly different among sites (p= 0.033), with no significant difference between years.  Incremental relative stock densities for the entire lower Platte River sturgeon population were: stock- to quality (1), quality- to preferred (6), preferred- to memorable (89), and memorable- to trophy (4).  The sturgeon in the Platte River appear to be healthy with greater population densities near the mouth.

 

 

 

Food Habits of Two Walleye Stocking Treatments in Minnesota Permanent Wetlands

 

Matthew C. Warda, David W. Willisa, Mark A. Hansonb, Brian R. Herwigb, Bradford G. Parsonsb, and Jeffrey R. Reedb

 

aDepartment of Wildlife and Fisheries Sciences

South Dakota State University, Brookings

bMinnesota Department of Natural Resources

 

Fathead minnows Pimephales promelas reduce aquatic invertebrate density, biomass and taxonomic diversity in prairie pothole wetlands, and thus may compete with waterfowl.  We undertook a biomanipulation project to assess the ability of walleyes Stizostedion vitreum to reduce fathead minnow abundance. Walleye diets were monitored from 12 permanent wetlands in west-central Minnesota during 2001. Six wetlands were stocked in May with age-0 walleyes and sampled bi-weekly from 1 June through 15 September. Diets were enumerated as percent composition by weight. A generalized diet shift from zooplankton to fish to macroinvertebrates was observed. Six other wetlands were stocked in May with 5.6 kg/ha of advanced walleyes and sampled monthly from mid-June through mid-September. Diets were enumerated as percent composition by weight. In four of the six wetlands in which fathead minnows were the only other fish species present, they composed from 84 to 100% of the walleye diets each month. Leeches (Hirudinidae) and tiger salamanders Ambystoma tigrinum composed the remaining portion of the diets. In two wetlands in which fathead minnows and brook sticklebacks Culaea inconstans were present, fathead minnows composed >63% of the walleye diets throughout June and July. However, in August and September, brook sticklebacks became more abundant in the diets (as much as 68%). Our results suggest that age-0 walleye diets were composed of zooplankton and macroinvertebrates throughout most of the sampling period, with the walleyes quickly reducing the abundance of fathead minnows. Our results also suggest that the stocking density used for advanced walleyes apparently was insufficient for reducing prey fish populations.


Abstracts:  Posters

 

Hermaphroditism Observed in Captive Fall Chinook Salmon Broodstock

 

Michael E. Barnes1, John M. Carreiro2, and Rick J. Cordes1

 

South Dakota Department of Game, Fish and Parks

1McNenny State Fish Hatchery, 19619 Trout Loop, Spearfish, South Dakota, 57783, (605)-642-6920

2Cleghorn Springs State Fish Hatchery, 4725 Rimrock Highway, Rapid City, South Dakota, 57702, (605)-394-4100

 

During spawning of a hatchery-maintained, landlocked strain of fall chinook salmon Oncorhynchus tshawytscha broodstock, an apparent female, based on secondary sex characteristics, was observed to release milt. Internal examination revealed two ovotestes, each containing an ovarian region with nearly ripe eggs, as well as prominent testicular regions.  A total of three testicular regions were observed, with two testiticular regions bracketing the ovary on one of the ovotestes.  Genetically, this fish was a male.  We believe this to be the first documented hermaphrodite from both a landlocked fall chinook salmon stock, and also from a hatchery-maintained chinook salmon broodstock.

 

 

 

Influence of Age-0 Yellow Perch Abundance on Walleye Populations in Two Eastern South Dakota Lakes

 

Daniel A. Isermann and David W. Willis, Department of Wildlife and Fisheries Sciences, South Dakota State University (605-688-6121); David O. Lucchesi and Todd R. St. Sauver, South Dakota Department of Game, Fish and Parks, Sioux Falls; and Brian G. Blackwell and Matthew J. Hubers, South Dakota Department of Game, Fish and Parks, Webster

 

Eastern South Dakota lakes typically range from mesotrophic to hypereutrophic based on the trophic state index.  Biologists often believe that prey supplies, whether they be macroinvertebrates or fishes, are abundant.  Thus, we  often believe that quality of sport fishing is more closely linked to interannual variation in recruitment (i.e., year-class strength) than to prey supplies for sport fishes.  Here, we document two case histories that challenge this premise.  We noted substantial increases in age-0 yellow perch Perca flavescens abundance between 2000 and 2001 in Sinai and Waubay lakes.  For example, larval yellow perch abundance (number/100 m3) was 723 times higher in 2001 in Lake Sinai and 46 times higher in Lake Waubay.  Similarly, juvenile yellow perch abundance as indexed by seine hauls increased by a factor of 251 in Waubay Lake and a factor of 385 in Lake Sinai between 2000 and 2001.  In conjunction with these increases in age-0 yellow perch as available prey, both condition and growth of walleyes Stizostedion vitreum increased in both lakes, although the most pronounced effects were noted for smaller (i.e., <38 cm) rather than larger walleyes.  Based on these case histories, we suggest that prey availability may be more important to sport fish population structure and dynamics in these lakes than previously believed.

 


 

Conservation Genetics of Topeka Shiner

 

Kristie Martin, Cynthia Anderson and Shane K. Sarver, Department of Biology, Black Hills State University, 1200 University Avenue, Spearfish, SD 57783, (605)-642-6043

 

The Topeka shiner is a small minnow-like fish that has declined significantly throughout its historic midwestern range.  Populations of Topeka shiner are now restricted to Kansas, Missouri, and South Dakota.  In 1999, the United States Fish and Wildlife Service listed the Topeka shiner as an endangered species.  If management plans for Topeka shiner are to include population enhancement, reintroduction of fish and/or hatchery propagation, the genetic diversity and population structure of existing populations must be understood.  DNA fingerprinting markers have been developed for Topeka shiner (Sarver, unpubl.) and now are being used to survey heterozygosity and examine population structure.  This paper will discuss Topeka shiner genetic research being conducted at Black Hills State University.

 

 

 

Comparison of Removal and Processing Times for Three Different Structures Used for Walleye Age Determination with Implications for Sampling

 

Jonathan R. Meerbeek*, George D. Scholten, Daniel A. Isermann1 and David W. Willis,

Department of Wildlife and Fisheries Sciences, Box 2140B, South Dakota State University, Brookings, SD 57007.

*presenter

1corresponding author, email: disermann@hotmail.com

 

We compared removal and processing times required when using scales, sagittal otoliths, and dorsal spines as age determination structures for 160 walleyes Stizostedion vitreum collected from six water bodies in South Dakota. All removal and processing times were estimated on a per 10 fish basis. On average, dorsal spines required the least amount of time for removal, followed by scales and otoliths. Whole view sagittal otoliths required no further manipulation prior to aging, while sectioning of dorsal spines and scale pressing required 12.4 - 17 min of additional processing time. However, otolith sectioning (by hand) may be required when aging older walleyes, which would add to processing times. Dorsal spines and scales also required significantly more time to age than whole view otoliths. Total processing time was significantly lower for otoliths, followed by scales and spines. Hence, fisheries personnel could save 22.5 – 30 h /1000 walleyes by using whole view otoliths as an aging structure rather than scales or dorsal spines. Additionally, reader agreement rates were markedly higher for otoliths (87%) than for dorsal spines (73%) or scales (51%). Based on our current results and findings reported in the literature, whole view otoliths likely provide the best approach for walleye age determination in terms of efficiency, accuracy, and precision. This would be especially true when annual gill net sampling (overnight sets) is used to monitor walleye populations and concerns over fish sacrifice and back-calculation of walleye growth rates would not be issues.

 

 

A Test to Compare Zooplankton Dynamics in Small Lakes With and Without Gizzard Shad

 

Tony Munter, University of Nebraska-Kearney, Department of Biology, 1617 1st Avenue, Kearney, NE 68847, (308) 440-6424, Muntera@lycos.com

 

Because of their middle position in the food web, introduced gizzard shad which feed on microscopic plants and animals (plankton) may dramatically reduce the plankton abundance in small sandpit lakes which could influence the recruitment of young-of-the-year game fish.  Although these effects have been hypothesized to reduce sport fish populations that occupy these small lakes, direct tests in Nebraska have not been conducted.  In this study, we measured the types and abundance of zooplankton present in four sandpit lakes, two of which contained gizzard shad and two of which did not.  We sampled each lake by plankton tow for three periods: June, July, and August.  Although our sand pit lakes were similar during the first period, the presence of gizzard shad significantly reduced the number of copepods, cladocera, and ostracods in these lakes by the third sample period.  These results indicate that gizzard shad can impact the food resources for young-of-the-year sport fish and they should be excluded from sand pit lakes.

 

 

 

Influences of Macrohabitat on Zooplankton Distribution and Abundance in a Small South Dakota Impoundment

 

Nathan W. Olson, Stephen K. Wilson, and David W. Willis

Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, South Dakota 57007, (605)-688-6121

 

Many fishery studies involving zooplankton abundance implement a sampling protocol that involves either sampling at randomly selected sites located throughout the water body, or sampling an equal number of times in near-shore and off-shore locations.  However, the validity of these techniques is rarely explored.  Therefore, the objective of this study was to assess potential differences in spatial and seasonal zooplankton abundance in a small (43 ha) South Dakota impoundment.  Zooplankton samples (n=8 fixed sites per category) were collected from vegetated (i.e., emergent/submergent), edge, and non-vegetated areas using a 1.5-m integrated tube sampler in May, June, and July 2001.  Overall, repeated measures analysis of variance tests suggested that zooplankton taxa exhibit seasonal and spatial differences in abundance.  For example, Cyclopoida number per liter (number/L) was higher in vegetated areas than edge or non-vegetated areas during all three months (P=0.0001).  Also, Cyclopoida were more abundant in May than in June (P=0.04).  These results suggest that estimates of zooplankton abundance in small South Dakota impoundments may be influenced by both aquatic vegetation and time of year.

 

 


Sample Size Requirements for In Situ Vegetation and Substrate Classifications in Shallow Nebraska Natural Lakes

 

Craig. P. Paukert, Department of Wildlife and Fisheries Sciences, PO Box 2140B, South Dakota State University, Bookings, SD 57007, 605-688-6121.

 

David W. Willis, Department of Wildlife and Fisheries Sciences, PO Box 2140B, South Dakota State University, Brookings, SD 57007, 605-688-6121.

 

Richard S. Holland, Nebraska Game and Parks Commission, PO Box 30370, Lincoln, NE 68701, 402-471-5501

 

Little research has focused on precision of habitat classification in lentic systems.  The objective of this study was to assess precision of visual estimates for vegetation and substrate in shallow natural lakes.  Transects across 15 shallow Nebraska natural lakes were established and vegetation type (submergent or emergent) and density (sparse, moderate, or dense), and substrate composition (sand, muck, and clay to the nearest 10%) were estimated at 25-70 sampling sites within each lake by two independent observers.  Observer agreement for vegetation type was 92%.  Agreement ranged from 62.5 to 90.1% for the percent composition of sand, clay, or muck.  Agreement was still high (72%) when vegetation was estimated to density.  Our relatively high agreement was likely attributable to the lakes having homogeneous habitats.  Nearly 90% of substrate sites were classified as 0% clay; over 68% of sites were classified as either 0 or 100% sand.  The number of sampling sites per lake needed to be 95% confident that we were within 10% of the true mean habitat composition was <40 when habitats were homogenous and always #100 sites when habitats were heterogeneous.  Our results suggest that relatively high precision is attainable for vegetation and substrate mapping in shallow natural lakes.

 

 

An Assessment of Stable Isotopes using Simulated Trophic Shifts

 

Jennifer L. Powell, Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, SD   57007, phone (605) 688-6121, fax (605) 688-4518, email jenerator7@hotmail.com

 

Michael L. Brown, Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, SD   57007, phone (605) 688-6121, fax (605) 688-4515, email michael_brown@sdstate.edu

 

Stable isotope analyses provide an understanding of material flows in ecosystems.  Common isotopes used in the analysis of food webs are δ13C and δ15N.  With increasing numbers of fisheries studies utilizing isotope analyses, there is a need for controlled experiments to determine the rates at which different body tissues respond isotopically to diet change.  Therefore, a time series experiment was conducted to assess changes in isotope signatures of three tissues (dorsal white muscle, liver, and intestine) in age-1 yellow perch Perca flavescens.  Four groups of yellow perch were each fed isotopically distinct diets (fathead minnows Pimephales promelas, mealworms Tenebrio molitor, a plant-based prepared diet, and a fishmeal/plant-based prepared diet) and their C and N signatures were allowed to adjust and reach equilibrium.  Diets then were switched among groups to simulate various trophic shifts.  Fish from each treatment group were periodically sacrificed and processed for mass spectrometric analyses of total C, δ12C, δ13C, δ15N, and their ratios.  The assimilation rate of the prepared diet signatures exceeded that of mealworms followed by fathead minnows.  Isotope analyses indicate that visceral tissues are the first to respond to diet change (three weeks post-diet switching) followed by liver (five and one-half weeks) and white muscle tissue (eight weeks).  Due to lags in isotope assimilation for different body tissues, whole body versus selection of a particular tissue should be specific to study objectives and sampling framework.

 

 

 

Evaluation of Highway Culvert Impacts on Topeka Shiner Streams

 

Jeffrey S. Shearer, Wildlife & Fisheries Sciences Dept., Box 2140B, SDSU, Brookings, SD  57007:  (605) 688-6121;  Steve Wall, , Wildlife & Fisheries Sciences Dept., Box 2140B, SDSU, Brookings, SD  57007;  Charles R. Berry, Jr.,  U.S. Geological Survey, SD Cooperative Fish & Wildlife Research Unit, SDSU, Brookings, SD  57007

 

Culverts used in highway and road construction can have negative impacts on the lifecycle of fish species, such as impeding movement during spawning, migration, and recolonization.  We evaluated culverts in stream reaches having high Topeka shiner (Notropis topeka) potential to determine where possible problems may occur throughout eastern South Dakota.  During the fall of 2001, we assessed culvert perching and counter sink, gradient, and blockage for 81 culverts at 27 crossings.  Qualitative measurements of substrate material, head cutting, bank height and incision, bed material transport, riparian zone, land use, and erosion controls were taken along the up and downstream reaches at each crossing.  Approximately 30% of culverts were embedded.  Culvert perching and gradient did not appear to be a barrier to fish movement.  Only three culverts were perched to a degree that fish migration would be blocked during spring and summer flows, similarly only three culverts had a slope > 3 cm/m.  Twenty-two percent of culverts were partially blocked with woody debris or bed materials either within or at culvert ends.  Clay, silt, and sand were the dominate substrate material and downstream head cutting was present at > 75% of the sites.  Other qualitative measurements varied from site to site.  Culvert assessments will continue during 2002, after which guidelines for best management practices and culvert mitigation will be developed.

 

 

 

An evaluation of the Effectiveness of Formalin and Hydrogen Peroxide Treatments on Microbe Levels of Chinook Salmon (Onchorhyncus tshawytscha) Eggs.

 

Hans Stephenson, Black Hills State University, Spearfish, SD

Mike Barnes, McNenny State Fish Hatchery, Spearfish, SD

Mark Gabel, Professor Black Hills State University, Spearfish, SD

 

The presence of bacteria and fungi in hatchery water stocks can have serious effects on the rearing of Chinook salmon (Onchorhyncus tshawytscha) eggs. Antimicrobial chemical treatments evaluated in this test were formalin and hydrogen peroxide. In an attempt to understand the unknown mechanisms by which these chemicals increase egg survival, we have begun analyses using scanning electron microscopy to determine microbe levels and changes in characteristics of the external egg membrane.  Initial observations indicate that formalin treated eggs have fewer microbes attached to the external egg membrane compared to peroxide and untreated control eggs.  Peroxide treatments proved to be variable, but were superior to no treatment.  Pore plugs in the external egg membrane exhibited a variable degree of degradation that may be related to chemical treatments.   

 

 


 

Thiamin Influences on Landlocked Fall Chinook Salmon Reproductive Characteristics

 

Michael E. Barnes1, Micheal H. Zehfus2, Kelly S. Stock2,  Jonathan A. Schumacher2, Faraz Farrokhi2, and Rebecca L. Nutter2

 

1South Dakota Department of Game, Fish and Parks, 19619 Trout Loop, Spearfish, South Dakota 57783-8905, (605)-642-6920

 

2Department of Chemistry, Black Hills State University, 1200

University, Spearfish, South Dakota  57799, (605)-642-6028

 

Maternal liver tissue and egg thiamine levels were analyzed from spawning landlocked fall chinook salmon (Oncorhynchus tshawytscha) from Lake Oahe, South Dakota.  Egg thiamine levels were not correlated to survival at egg eye-up, hatch, fry swim-up, or the number of days of fry survival beyond complete yolk sac absorption.  However, egg thiamine concentrations were significantly correlated with total egg numbers.  Egg and liver thiamine levels were not correlated.  Liver thiamine was also not correlated to female length, weight, egg number, or egg size.  Mean embryo survival was greater than 70 percent.  The relatively high thiamine levels, along with the high embryo survival observed, were likely influenced by dietary shifts of adult chinook salmon during a year of very low rainbow smelt (Osmerus mordax) availability.

 

 

 

Seasonal Food Habits of Yellow Perch in West Long Lake, Nebraska

 

Justin L. Wilkens, Timothy J. DeBates, and David W. Willis

Department of Wildlife and Fisheries Sciences, PO Box 2140B, South Dakota State University, Brookings, SD 57007

 

We compared the seasonal food habits of yellow perch Perca flavescens in West Long Lake with glacial lakes of South Dakota and Minnesota to evaluate if diet ontogeny shifts from macroinvertebrates to fish in these systems.  Macroinvertebrates dominated the dietary habits of yellow perch in all length groups and seasons in West Long Lake with chironomids and amphipods comprising the bulk of the stomach contents (% by weight).  Yellow perch in glacial lakes of eastern South Dakota had similar diets.   Macroinvertebrates, primarily consisting of chironomids, amphipods, and corixids, were important dietary items in all lakes.  On the contrary, fish were the primary prey source (% by weight) of yellow perch in west-central Minnesota lakes.  Knowledge of the trophic ecology of yellow perch in various lentic systems should help biologists better understand the role of yellow perch as both predators and prey. 

 

 

 


 

Seasonal Variation in Electrofishing Data for Largemouth Bass Collected from a South Dakota Glacial Lake

 

William L. McKibbin and David W. Willis, Wildlife and Fisheries Sciences, South Dakota State University, 605-688-6121; and Brian G. Blackwell, South Dakota Department of Game, Fish and Parks