Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report.
Pelagic fishes, such as kokanee and rainbow trout, provide an important fishery in Lake Roosevelt; however, spawner returns and creel results have been below management goals in recent years. Our objective was to identify factors that potentially limit pelagic fish production in Lake Roosevelt inclu...
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Format: | Report |
Language: | English |
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United States. Bonneville Power Administration.
2002
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Online Access: | https://doi.org/10.2172/961979 https://digital.library.unt.edu/ark:/67531/metadc925692/ |
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ftunivnotexas:info:ark/67531/metadc925692 |
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Open Polar |
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University of North Texas: UNT Digital Library |
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ftunivnotexas |
language |
English |
topic |
Biomass Abundance Oxygen Food Management Lakes Diet Entrainment Fisheries Turbines Fishes Dissolved Gases 13 Hydro Energy Zooplankton Trout Evaluation Daphnia |
spellingShingle |
Biomass Abundance Oxygen Food Management Lakes Diet Entrainment Fisheries Turbines Fishes Dissolved Gases 13 Hydro Energy Zooplankton Trout Evaluation Daphnia Baldwin, Casey Polacek, Matt Bonar, Scott Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. |
topic_facet |
Biomass Abundance Oxygen Food Management Lakes Diet Entrainment Fisheries Turbines Fishes Dissolved Gases 13 Hydro Energy Zooplankton Trout Evaluation Daphnia |
description |
Pelagic fishes, such as kokanee and rainbow trout, provide an important fishery in Lake Roosevelt; however, spawner returns and creel results have been below management goals in recent years. Our objective was to identify factors that potentially limit pelagic fish production in Lake Roosevelt including entrainment, food limitation, piscivory, and other abiotic factors. We estimated the ratio of total fish entrained through Grand Coulee Dam to the pelagic fish abundance for September and October, 1998. If the majority of these fish were pelagic species, then entrainment averaged 10-13% of pelagic fish abundance each month. This rate of entrainment could impose considerable losses to pelagic fish populations on an annual basis. Therefore, estimates of species composition of entrained fish will be important in upcoming years to estimate the proportion of stocked pelagic fish lost through the dam. Food was not limiting for kokanee or rainbow trout populations since growth rates were high and large zooplankton were present in the reservoir. Estimates of survival for kokanee were low (< 0.01 annual) and unknown for rainbow trout. We estimated that the 1997 standing stock biomass of large (>1.1 mm) Daphnia could have supported 0.08 annual survival by kokanee and rainbow trout before fish consumption would have exceeded available biomass during late winter and early spring. Therefore, if recruitment goals are met in the future there may be a bottleneck in food supply for pelagic planktivores. Walleye and northern pikeminnow were the primary piscivores of salmonids in 1996 and 1997. Predation on salmonid prey was rare for rainbow trout and not detected for burbot or smallmouth bass. Northern pikeminnow had the greatest individual potential as a salmonid predator due to their high consumptive demand; however, their overall impact was limited because of their low relative abundance. We modeled the predation impact of 273,524 walleye in 1996, and 39,075 northern pikeminnow in 1997 because diet data revealed predation on salmonids during these years. We could not determine the absolute impact of piscivores on each salmonid species because identification of fish prey was limited to families. Our estimate of salmonid consumption by walleye in 1996 and northern pikeminnow in 1997 shows that losses of stocked kokanee and rainbow trout could be substantial (up to 73% of kokanee) if piscivores were concentrating on one salmonid species, but were most likely lower, assuming predation was spread among kokanee, rainbow trout, and whitefish. Dissolved oxygen was never limiting for kokanee or rainbow trout, but temperatures were up to 6 EC above the growth optimum for kokanee from July to September in the upper 33 meters of water. Critical data needed for a more complete analysis in the future include species composition of entrainment estimates, entrainment estimates expanded to include unmonitored turbines, seasonal growth of planktivorous salmonids, species composition of salmonid prey, piscivore diet during hatchery releases of salmonids, and collection of temperature and dissolved oxygen data throughout all depths of the reservoir during warm summer months. |
author2 |
United States. Department of Energy. |
format |
Report |
author |
Baldwin, Casey Polacek, Matt Bonar, Scott |
author_facet |
Baldwin, Casey Polacek, Matt Bonar, Scott |
author_sort |
Baldwin, Casey |
title |
Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. |
title_short |
Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. |
title_full |
Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. |
title_fullStr |
Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. |
title_full_unstemmed |
Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. |
title_sort |
lake roosevelt fisheries evaluation program, part c; lake roosevelt pelagic fish study: washington department of fish and wildlife, 1998 annual report. |
publisher |
United States. Bonneville Power Administration. |
publishDate |
2002 |
url |
https://doi.org/10.2172/961979 https://digital.library.unt.edu/ark:/67531/metadc925692/ |
genre |
Burbot |
genre_facet |
Burbot |
op_relation |
rep-no: DOE/BP-32148-6 doi:10.2172/961979 osti: 961979 https://digital.library.unt.edu/ark:/67531/metadc925692/ ark: ark:/67531/metadc925692 |
op_doi |
https://doi.org/10.2172/961979 |
_version_ |
1766382108970844160 |
spelling |
ftunivnotexas:info:ark/67531/metadc925692 2023-05-15T15:47:20+02:00 Lake Roosevelt Fisheries Evaluation Program, Part C; Lake Roosevelt Pelagic Fish Study: Washington Department of Fish and Wildlife, 1998 Annual Report. Baldwin, Casey Polacek, Matt Bonar, Scott United States. Department of Energy. 2002-11-01 69 pges Text https://doi.org/10.2172/961979 https://digital.library.unt.edu/ark:/67531/metadc925692/ English eng United States. Bonneville Power Administration. rep-no: DOE/BP-32148-6 doi:10.2172/961979 osti: 961979 https://digital.library.unt.edu/ark:/67531/metadc925692/ ark: ark:/67531/metadc925692 Biomass Abundance Oxygen Food Management Lakes Diet Entrainment Fisheries Turbines Fishes Dissolved Gases 13 Hydro Energy Zooplankton Trout Evaluation Daphnia Report 2002 ftunivnotexas https://doi.org/10.2172/961979 2019-05-18T22:08:18Z Pelagic fishes, such as kokanee and rainbow trout, provide an important fishery in Lake Roosevelt; however, spawner returns and creel results have been below management goals in recent years. Our objective was to identify factors that potentially limit pelagic fish production in Lake Roosevelt including entrainment, food limitation, piscivory, and other abiotic factors. We estimated the ratio of total fish entrained through Grand Coulee Dam to the pelagic fish abundance for September and October, 1998. If the majority of these fish were pelagic species, then entrainment averaged 10-13% of pelagic fish abundance each month. This rate of entrainment could impose considerable losses to pelagic fish populations on an annual basis. Therefore, estimates of species composition of entrained fish will be important in upcoming years to estimate the proportion of stocked pelagic fish lost through the dam. Food was not limiting for kokanee or rainbow trout populations since growth rates were high and large zooplankton were present in the reservoir. Estimates of survival for kokanee were low (< 0.01 annual) and unknown for rainbow trout. We estimated that the 1997 standing stock biomass of large (>1.1 mm) Daphnia could have supported 0.08 annual survival by kokanee and rainbow trout before fish consumption would have exceeded available biomass during late winter and early spring. Therefore, if recruitment goals are met in the future there may be a bottleneck in food supply for pelagic planktivores. Walleye and northern pikeminnow were the primary piscivores of salmonids in 1996 and 1997. Predation on salmonid prey was rare for rainbow trout and not detected for burbot or smallmouth bass. Northern pikeminnow had the greatest individual potential as a salmonid predator due to their high consumptive demand; however, their overall impact was limited because of their low relative abundance. We modeled the predation impact of 273,524 walleye in 1996, and 39,075 northern pikeminnow in 1997 because diet data revealed predation on salmonids during these years. We could not determine the absolute impact of piscivores on each salmonid species because identification of fish prey was limited to families. Our estimate of salmonid consumption by walleye in 1996 and northern pikeminnow in 1997 shows that losses of stocked kokanee and rainbow trout could be substantial (up to 73% of kokanee) if piscivores were concentrating on one salmonid species, but were most likely lower, assuming predation was spread among kokanee, rainbow trout, and whitefish. Dissolved oxygen was never limiting for kokanee or rainbow trout, but temperatures were up to 6 EC above the growth optimum for kokanee from July to September in the upper 33 meters of water. Critical data needed for a more complete analysis in the future include species composition of entrainment estimates, entrainment estimates expanded to include unmonitored turbines, seasonal growth of planktivorous salmonids, species composition of salmonid prey, piscivore diet during hatchery releases of salmonids, and collection of temperature and dissolved oxygen data throughout all depths of the reservoir during warm summer months. Report Burbot University of North Texas: UNT Digital Library |