Jason McLellan | Colville Tribes (original) (raw)

Papers by Jason McLellan

Research paper thumbnail of Estimates of Chinook Salmon Spawning Habitat in a Blocked Reach of the Columbia River Upstream of Grand Coulee Dam

Northwest Science, 2020

The physical excitations entering the effective Lagrangian for quantum black holes are related to... more The physical excitations entering the effective Lagrangian for quantum black holes are related to a Goldstone boson which is present in the Rindler limit and is due to the spontaneous breaking of the translation symmetry of the underlying Minkowski space. This physical interpretation, which closely parallels similar well-known results for the effective stringlike description of flux tubes in QCD, gives a physical insight into the problem of describing the quantum degrees of freedom of black holes. It also suggests that the recently suggested concept of 'black hole complementarity' emerges at the effective Lagrangian level rather than at the fundamental level.

Research paper thumbnail of Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2001 Annual Report

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL... more In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power Planning Council (NPPC). The NPPC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation

Research paper thumbnail of Lake Roosevelt White Sturgeon Recovery Project : Annual Progress Report, January 2003 ? March 2004

This report summarizes catch data collected from white sturgeon Acipenser transmontanus in Lake R... more This report summarizes catch data collected from white sturgeon Acipenser transmontanus in Lake Roosevelt during limited setlining and gill netting activities in the fall of 2003, and documents progress toward development of a U.S. white sturgeon conservation aquaculture program for Lake Roosevelt. From 27-30 October, 42 overnight small mesh gill net sets were made between Marcus and Northport, WA for a total catch of 15 juvenile white sturgeon (275-488 mm FL). All sturgeon captured were of Canadian hatchery origin. These fish had been previously released as sub-yearlings into the Canadian portion (Keenleyside Reach) of the Transboundary Reach of the Columbia River during 2002 and 2003. Most sturgeon (n=14) were caught in the most upstream area sampled (Northport) in low velocity eddy areas. Five fish exhibited pectoral fin deformities (curled or stunted). Growth rates were less than for juvenile sturgeon captured in the Keenleyside Reach but condition factor was similar. Condition factor was also similar to that observed in juvenile sturgeon (ages 1-8) captured in the unimpounded Columbia River below Bonneville Dam between 1987-92. From 10-14 November, 28 overnight setline sets were made in the Roosevelt Reach between the confluence of the Spokane River and Marcus Island for a total catch of 17 white sturgeon (94-213 cm FL). Catch was greatest in the most upstream areas sampled, a distribution similar to that observed during a WDFW setline survey in Lake Roosevelt in 1998. The mean W r index of 110% for fish captured this year was higher than the mean Wr of 91% for fish captured in 1998. Excellent fish condition hindered surgical examination of gonads as lipid deposits made the ventral body wall very thick and difficult to penetrate with available otoscope specula. Acoustic tags (Vemco model V16 coded pingers, 69 kHz, 48-month life expectancy) were internally applied to 15 fish for subsequent telemetry investigations of seasonal and reproductively motivated movements. In August 2003, three Vemco VR2 fixed station acoustic receivers, supplied by the UCWSRI Transboundary Telemetry Project, were deployed in the vicinities of Kettle Falls Bridge, Marcus Island, and Northport, WA. Data downloaded from these receivers through December 2003 confirmed the findings of a previous telemetry study that the Marcus area is an important overwintering habitat for white sturgeon. On 18 February 2004, juvenile white sturgeon (n=2,000) were transported from Kootenay Sturgeon Hatchery in British Columbia to WDFW Columbia Basin Hatchery (CBH) in Moses Lake, WA. Fish were reared at CBH to approximately 30 g and individually outfitted with PIT tags and scute marked. On 11 May 2004, fish were released into Lake Roosevelt in the vicinities of Kettle Falls Bridge, North Gorge, and Northport.

Research paper thumbnail of Contributions to Fisheries Management in Eastern Washington State Number 3, March 2002

lrf.org

... Annual Report 1999 Prepared by: Jason G. McLellan 1 Holly J. McLellan And Allan T. Scholz ...... more ... Annual Report 1999 Prepared by: Jason G. McLellan 1 Holly J. McLellan And Allan T. Scholz ... We also thank John Hoskins, Tom Steen, and Buster Hill of Eastern Washington University for equipment, boat, and vehicle repairs. ...

Research paper thumbnail of Assessment of the Lake Roosevelt Walleye Population

... Francis (Colville Tribe), Mike McCartney (Colville Tribe), and Eastern Washington University ... more ... Francis (Colville Tribe), Mike McCartney (Colville Tribe), and Eastern Washington University students – James Hudson, Teresa Nelson, Melissa Buchanan, Leslie Holub, Suzanne Canwell, Chamisa Bird, and Cha Vang – for helping ... (Spokane Tribe), Leroy Williams (Colville ...

Research paper thumbnail of Vulnerability of larval and juvenile white sturgeon to barotrauma: can they handle the pressure?

Conservation Physiology, 2013

Techniques were developed to determine which life stages of fish are vulnerable to barotrauma fro... more Techniques were developed to determine which life stages of fish are vulnerable to barotrauma from expansion of internal gases during decompression. Eggs, larvae, and juvenile hatchery-reared white sturgeon (Acipenser transmontanus; up to 91 days post hatch; d.p.h.) were decompressed to assess vulnerability to barotrauma and identify initial swim bladder inflation. Barotrauma-related injury and mortality were first observed 9 d.p.h., on the same day as initial exogenous feeding. However, barotrauma-related injury did not occur again until swim bladder inflation 75 d.p.h. (visible at necropsy and on radiographs). Swim bladder inflation was not consistent among individuals, with only 44% being inflated 91 d.p.h. Additionally, swim bladder inflation did not appear to be size dependent among fish ranging in total length from 61 to 153 mm at 91 d.p.h. The use of a combination of decompression tests and radiography was validated as a method to determine initial swim bladder inflation and vulnerability to barotrauma. Extending these techniques to other species and lifehistory stages would help to determine the susceptibility of fish to hydro turbine passage and aid in fish conservation.

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program : Lake Whatcom Kokanee Salmon (Oncorhynchus nerka kennerlyi) : Investigations in Lake Roosevelt Annual Report 1999-2000

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program : Lake Whatcom Kokanee Salmon (Oncorhynchus nerka kennerlyi) : Investigations in Lake Roosevelt Annual Report 1999-2000

Research paper thumbnail of Characteristics of the Kokanee Spawning Run in Harvey Creek, Washington, and its Potential Use as an Egg Source

Research paper thumbnail of Evaluation of release strategies for hatchery kokanee in Lake Roosevelt, Washington

Research paper thumbnail of Fisheries Survey of the Limnetic Zone of Sullivan Lake, Washington, Using Hydroacoustics and Gill Nets, September 2003

Research paper thumbnail of Use of Gill Nets for Target Verification of a Hydroacoustic Fisheries Survey and Comparison with Kokanee Spawner Escapement Estimates from a Tributary Trap

North American Journal of Fisheries Management, 2008

The focus of this study was to determine whether gill nets are a valid method for assessing speci... more The focus of this study was to determine whether gill nets are a valid method for assessing species composition for a hydroacoustic survey and whether the hydroacoustic and gill-net survey could be used to forecast the spawn escapement of kokanee Oncorhynchus nerka so as to allow fisheries managers to plan ahead for egg takes at Sullivan Lake, Washington. We conducted

Research paper thumbnail of Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2000 Annual Report

The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, commonly known a... more The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, commonly known as the Joint Stock Assessment Project (JSAP) is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (blocked area). The three-phase approach of this

Research paper thumbnail of Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2002-2003 Annual Report

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL... more In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by ...

Research paper thumbnail of Resident Fish Stock above Chief Joseph and Grand Coulee Dams; 2003-2004 Annual Report

Description/Abstract In 1980, the United States Congress enacted the Northwest Power Planning and... more Description/Abstract In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The ...

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program; Assessment of the Lake Roosevelt Walleye Population: Compilation of 1997-1999 Data, 1999-2000 Annual Report

A walleye mark-recapture study was conducted on Lake Roosevelt between 1997 and 1999. The primary... more A walleye mark-recapture study was conducted on Lake Roosevelt between 1997 and 1999. The primary objective of the study was to describe the status and biological characteristics of the walleye population in Lake Roosevelt by determining its abundance, movement patterns, age structure, growth, condition, and mortality. The abundance estimates were also to be used to estimate the consumptive impact of

Research paper thumbnail of Fine-Scale Population Structure of Rainbow Trout in the Spokane River Drainage in Relation to Hatchery Stocking and Barriers

Transactions of the American Fisheries Society, 2007

We used 13 microsatellite loci to examine population structure in rainbow trout Oncorhynchus myki... more We used 13 microsatellite loci to examine population structure in rainbow trout Oncorhynchus mykiss collected from 20 tributaries and 3 main stems in the greater Spokane River drainage. Populations displayed some excess homozygosity and linkage disequilibrium, which was more pronounced in upper tributary collections and probably the result of small effective population sizes or structuring within tributaries. In general, population structure followed geographic structure; collections from creeks within subdrainages were the most closely related, and collections from different tributaries were genetically distinct. Comparisons with cutthroat trout O. clarkii indicated little to no introgression. Comparisons with steelhead (anadromous rainbow trout), coastal rainbow trout O. mykiss irideus, and inland rainbow trout from hatcheries suggested introgression by hatchery fish into some wild populations. Introgression was suspected in populations from stocked tributaries and tributaries that lacked barriers to escaped hatchery fish. Populations from tributaries above barriers that had not been stocked were genetically distinct from hatchery fish and appeared to be native inland redband trout O. mykiss gairdneri.

Research paper thumbnail of Walleye Predation on Hatchery Releases of Kokanees and Rainbow Trout in Lake Roosevelt, Washington

North American Journal of Fisheries Management, 2003

Recruitment failures of stocked kokanees (lacustrine sockeye salmon Oncorhynchus nerka) in Lake R... more Recruitment failures of stocked kokanees (lacustrine sockeye salmon Oncorhynchus nerka) in Lake Roosevelt have led to examination of various limiting factors. We evaluated the predatory impacts of piscivores on hatchery-released and net-pen-released kokanees and rainbow trout O. mykiss from the Sherman Creek Hatchery in 1999 and 2000. We used an angler tournament to mark walleyes Stizostedion vitreum for an abundance estimate, and then used gillnetting and electrofishing to collect recaptures and monitor the diet of walleyes. A bioenergetics model was used to quantify consumption, and estimates were extrapolated to walleye abundance to determine a percent loss of hatchery fish. Kokanees averaged 22-100% of the diet contents of walleyes (Ͼ300 mm total length), whereas rainbow trout averaged 0-25%, depending on location and timing following release. In 1999, we estimated that 16,610 walleyes consumed 15% of the hatchery kokanees within 41 d of release; however, our diet information did not correspond spatially with our population estimate. In 2000, we corrected our spatial bias and estimated that the population of 12,233 walleyes consumed 9.4% of the hatchery kokanees and 7.3% of the hatchery rainbow trout within 41 d of release. We conclude that the walleye population in northern Lake Roosevelt was effectively ''swamped'' by the biomass of salmonids released at the Sherman Creek Hatchery. However, piscivores may still limit kokanee recruitment, depending on long-term predation rates for the reservoir-wide walleye population.

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program, Assessment of the Lake Roosevelt Walleye Population 1998 Annual Report, Part D

A walleye mark-recapture experiment was initiated on Lake Roosevelt in 1997, with the primary obj... more A walleye mark-recapture experiment was initiated on Lake Roosevelt in 1997, with the primary objective of estimating the size of the walleye population. The project was continued in 1998 with a revised sampling regime. The primary goals during 1998 were to estimate the size of the walleye population in Lake Roosevelt, estimate the size of the spawning run in the Spokane River Arm, and describe the age structure of the population for use in managing the population and developing a kokanee bioenergetics model. Secondary objectives included: determining walleye movements, back-calculating growth rates, estimating mortality rates, determining walleye condition, and estimating walleye young-of-the-year (YOY) production in the Spokane River Arm. All walleye, 150 mm TL, were marked with individually numbered Floy{reg_sign} tags, during five passes through the reservoir. The passes occurred between April 1st and September 16th, 1998. The most unbiased estimate of walleye abundance in Lake ...

Research paper thumbnail of Estimates of Chinook Salmon Spawning Habitat in a Blocked Reach of the Columbia River Upstream of Grand Coulee Dam

Northwest Science, 2020

The physical excitations entering the effective Lagrangian for quantum black holes are related to... more The physical excitations entering the effective Lagrangian for quantum black holes are related to a Goldstone boson which is present in the Rindler limit and is due to the spontaneous breaking of the translation symmetry of the underlying Minkowski space. This physical interpretation, which closely parallels similar well-known results for the effective stringlike description of flux tubes in QCD, gives a physical insight into the problem of describing the quantum degrees of freedom of black holes. It also suggests that the recently suggested concept of 'black hole complementarity' emerges at the effective Lagrangian level rather than at the fundamental level.

Research paper thumbnail of Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2001 Annual Report

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL... more In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power Planning Council (NPPC). The NPPC was directed by Congress to develop a regional Power Plan and also the Columbia River Basin Fish and Wildlife Program (FWP) to restore or replace losses of fish caused by construction and operation

Research paper thumbnail of Lake Roosevelt White Sturgeon Recovery Project : Annual Progress Report, January 2003 ? March 2004

This report summarizes catch data collected from white sturgeon Acipenser transmontanus in Lake R... more This report summarizes catch data collected from white sturgeon Acipenser transmontanus in Lake Roosevelt during limited setlining and gill netting activities in the fall of 2003, and documents progress toward development of a U.S. white sturgeon conservation aquaculture program for Lake Roosevelt. From 27-30 October, 42 overnight small mesh gill net sets were made between Marcus and Northport, WA for a total catch of 15 juvenile white sturgeon (275-488 mm FL). All sturgeon captured were of Canadian hatchery origin. These fish had been previously released as sub-yearlings into the Canadian portion (Keenleyside Reach) of the Transboundary Reach of the Columbia River during 2002 and 2003. Most sturgeon (n=14) were caught in the most upstream area sampled (Northport) in low velocity eddy areas. Five fish exhibited pectoral fin deformities (curled or stunted). Growth rates were less than for juvenile sturgeon captured in the Keenleyside Reach but condition factor was similar. Condition factor was also similar to that observed in juvenile sturgeon (ages 1-8) captured in the unimpounded Columbia River below Bonneville Dam between 1987-92. From 10-14 November, 28 overnight setline sets were made in the Roosevelt Reach between the confluence of the Spokane River and Marcus Island for a total catch of 17 white sturgeon (94-213 cm FL). Catch was greatest in the most upstream areas sampled, a distribution similar to that observed during a WDFW setline survey in Lake Roosevelt in 1998. The mean W r index of 110% for fish captured this year was higher than the mean Wr of 91% for fish captured in 1998. Excellent fish condition hindered surgical examination of gonads as lipid deposits made the ventral body wall very thick and difficult to penetrate with available otoscope specula. Acoustic tags (Vemco model V16 coded pingers, 69 kHz, 48-month life expectancy) were internally applied to 15 fish for subsequent telemetry investigations of seasonal and reproductively motivated movements. In August 2003, three Vemco VR2 fixed station acoustic receivers, supplied by the UCWSRI Transboundary Telemetry Project, were deployed in the vicinities of Kettle Falls Bridge, Marcus Island, and Northport, WA. Data downloaded from these receivers through December 2003 confirmed the findings of a previous telemetry study that the Marcus area is an important overwintering habitat for white sturgeon. On 18 February 2004, juvenile white sturgeon (n=2,000) were transported from Kootenay Sturgeon Hatchery in British Columbia to WDFW Columbia Basin Hatchery (CBH) in Moses Lake, WA. Fish were reared at CBH to approximately 30 g and individually outfitted with PIT tags and scute marked. On 11 May 2004, fish were released into Lake Roosevelt in the vicinities of Kettle Falls Bridge, North Gorge, and Northport.

Research paper thumbnail of Contributions to Fisheries Management in Eastern Washington State Number 3, March 2002

lrf.org

... Annual Report 1999 Prepared by: Jason G. McLellan 1 Holly J. McLellan And Allan T. Scholz ...... more ... Annual Report 1999 Prepared by: Jason G. McLellan 1 Holly J. McLellan And Allan T. Scholz ... We also thank John Hoskins, Tom Steen, and Buster Hill of Eastern Washington University for equipment, boat, and vehicle repairs. ...

Research paper thumbnail of Assessment of the Lake Roosevelt Walleye Population

... Francis (Colville Tribe), Mike McCartney (Colville Tribe), and Eastern Washington University ... more ... Francis (Colville Tribe), Mike McCartney (Colville Tribe), and Eastern Washington University students – James Hudson, Teresa Nelson, Melissa Buchanan, Leslie Holub, Suzanne Canwell, Chamisa Bird, and Cha Vang – for helping ... (Spokane Tribe), Leroy Williams (Colville ...

Research paper thumbnail of Vulnerability of larval and juvenile white sturgeon to barotrauma: can they handle the pressure?

Conservation Physiology, 2013

Techniques were developed to determine which life stages of fish are vulnerable to barotrauma fro... more Techniques were developed to determine which life stages of fish are vulnerable to barotrauma from expansion of internal gases during decompression. Eggs, larvae, and juvenile hatchery-reared white sturgeon (Acipenser transmontanus; up to 91 days post hatch; d.p.h.) were decompressed to assess vulnerability to barotrauma and identify initial swim bladder inflation. Barotrauma-related injury and mortality were first observed 9 d.p.h., on the same day as initial exogenous feeding. However, barotrauma-related injury did not occur again until swim bladder inflation 75 d.p.h. (visible at necropsy and on radiographs). Swim bladder inflation was not consistent among individuals, with only 44% being inflated 91 d.p.h. Additionally, swim bladder inflation did not appear to be size dependent among fish ranging in total length from 61 to 153 mm at 91 d.p.h. The use of a combination of decompression tests and radiography was validated as a method to determine initial swim bladder inflation and vulnerability to barotrauma. Extending these techniques to other species and lifehistory stages would help to determine the susceptibility of fish to hydro turbine passage and aid in fish conservation.

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program : Lake Whatcom Kokanee Salmon (Oncorhynchus nerka kennerlyi) : Investigations in Lake Roosevelt Annual Report 1999-2000

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program : Lake Whatcom Kokanee Salmon (Oncorhynchus nerka kennerlyi) : Investigations in Lake Roosevelt Annual Report 1999-2000

Research paper thumbnail of Characteristics of the Kokanee Spawning Run in Harvey Creek, Washington, and its Potential Use as an Egg Source

Research paper thumbnail of Evaluation of release strategies for hatchery kokanee in Lake Roosevelt, Washington

Research paper thumbnail of Fisheries Survey of the Limnetic Zone of Sullivan Lake, Washington, Using Hydroacoustics and Gill Nets, September 2003

Research paper thumbnail of Use of Gill Nets for Target Verification of a Hydroacoustic Fisheries Survey and Comparison with Kokanee Spawner Escapement Estimates from a Tributary Trap

North American Journal of Fisheries Management, 2008

The focus of this study was to determine whether gill nets are a valid method for assessing speci... more The focus of this study was to determine whether gill nets are a valid method for assessing species composition for a hydroacoustic survey and whether the hydroacoustic and gill-net survey could be used to forecast the spawn escapement of kokanee Oncorhynchus nerka so as to allow fisheries managers to plan ahead for egg takes at Sullivan Lake, Washington. We conducted

Research paper thumbnail of Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2000 Annual Report

The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, commonly known a... more The Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams Project, commonly known as the Joint Stock Assessment Project (JSAP) is a management tool using ecosystem principles to manage artificial fish assemblages and native fish in altered environments existing in the Columbia River System above Chief Joseph and Grand Coulee Dams (blocked area). The three-phase approach of this

Research paper thumbnail of Resident Fish Stock Status above Chief Joseph and Grand Coulee Dams; 2002-2003 Annual Report

In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL... more In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The NPCC was directed by ...

Research paper thumbnail of Resident Fish Stock above Chief Joseph and Grand Coulee Dams; 2003-2004 Annual Report

Description/Abstract In 1980, the United States Congress enacted the Northwest Power Planning and... more Description/Abstract In 1980, the United States Congress enacted the Northwest Power Planning and Conservation Act (PL 96-501, 1980), which established the Northwest Power and Conservation Council (NPCC), formerly the Northwest Power Planning Council. The ...

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program; Assessment of the Lake Roosevelt Walleye Population: Compilation of 1997-1999 Data, 1999-2000 Annual Report

A walleye mark-recapture study was conducted on Lake Roosevelt between 1997 and 1999. The primary... more A walleye mark-recapture study was conducted on Lake Roosevelt between 1997 and 1999. The primary objective of the study was to describe the status and biological characteristics of the walleye population in Lake Roosevelt by determining its abundance, movement patterns, age structure, growth, condition, and mortality. The abundance estimates were also to be used to estimate the consumptive impact of

Research paper thumbnail of Fine-Scale Population Structure of Rainbow Trout in the Spokane River Drainage in Relation to Hatchery Stocking and Barriers

Transactions of the American Fisheries Society, 2007

We used 13 microsatellite loci to examine population structure in rainbow trout Oncorhynchus myki... more We used 13 microsatellite loci to examine population structure in rainbow trout Oncorhynchus mykiss collected from 20 tributaries and 3 main stems in the greater Spokane River drainage. Populations displayed some excess homozygosity and linkage disequilibrium, which was more pronounced in upper tributary collections and probably the result of small effective population sizes or structuring within tributaries. In general, population structure followed geographic structure; collections from creeks within subdrainages were the most closely related, and collections from different tributaries were genetically distinct. Comparisons with cutthroat trout O. clarkii indicated little to no introgression. Comparisons with steelhead (anadromous rainbow trout), coastal rainbow trout O. mykiss irideus, and inland rainbow trout from hatcheries suggested introgression by hatchery fish into some wild populations. Introgression was suspected in populations from stocked tributaries and tributaries that lacked barriers to escaped hatchery fish. Populations from tributaries above barriers that had not been stocked were genetically distinct from hatchery fish and appeared to be native inland redband trout O. mykiss gairdneri.

Research paper thumbnail of Walleye Predation on Hatchery Releases of Kokanees and Rainbow Trout in Lake Roosevelt, Washington

North American Journal of Fisheries Management, 2003

Recruitment failures of stocked kokanees (lacustrine sockeye salmon Oncorhynchus nerka) in Lake R... more Recruitment failures of stocked kokanees (lacustrine sockeye salmon Oncorhynchus nerka) in Lake Roosevelt have led to examination of various limiting factors. We evaluated the predatory impacts of piscivores on hatchery-released and net-pen-released kokanees and rainbow trout O. mykiss from the Sherman Creek Hatchery in 1999 and 2000. We used an angler tournament to mark walleyes Stizostedion vitreum for an abundance estimate, and then used gillnetting and electrofishing to collect recaptures and monitor the diet of walleyes. A bioenergetics model was used to quantify consumption, and estimates were extrapolated to walleye abundance to determine a percent loss of hatchery fish. Kokanees averaged 22-100% of the diet contents of walleyes (Ͼ300 mm total length), whereas rainbow trout averaged 0-25%, depending on location and timing following release. In 1999, we estimated that 16,610 walleyes consumed 15% of the hatchery kokanees within 41 d of release; however, our diet information did not correspond spatially with our population estimate. In 2000, we corrected our spatial bias and estimated that the population of 12,233 walleyes consumed 9.4% of the hatchery kokanees and 7.3% of the hatchery rainbow trout within 41 d of release. We conclude that the walleye population in northern Lake Roosevelt was effectively ''swamped'' by the biomass of salmonids released at the Sherman Creek Hatchery. However, piscivores may still limit kokanee recruitment, depending on long-term predation rates for the reservoir-wide walleye population.

Research paper thumbnail of Lake Roosevelt Fisheries Evaluation Program, Assessment of the Lake Roosevelt Walleye Population 1998 Annual Report, Part D

A walleye mark-recapture experiment was initiated on Lake Roosevelt in 1997, with the primary obj... more A walleye mark-recapture experiment was initiated on Lake Roosevelt in 1997, with the primary objective of estimating the size of the walleye population. The project was continued in 1998 with a revised sampling regime. The primary goals during 1998 were to estimate the size of the walleye population in Lake Roosevelt, estimate the size of the spawning run in the Spokane River Arm, and describe the age structure of the population for use in managing the population and developing a kokanee bioenergetics model. Secondary objectives included: determining walleye movements, back-calculating growth rates, estimating mortality rates, determining walleye condition, and estimating walleye young-of-the-year (YOY) production in the Spokane River Arm. All walleye, 150 mm TL, were marked with individually numbered Floy{reg_sign} tags, during five passes through the reservoir. The passes occurred between April 1st and September 16th, 1998. The most unbiased estimate of walleye abundance in Lake ...