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Evaluate recreational and commercial mark-selective fisheries.
(35018)
Geraldine Vander Haegen, WDFW
Charmane Ashbrook, WDFW
Chris Peery, U. Idaho
Annette Hoffman, WDFW
Background• 2001 Experiments – Spring Chinook
– 3.5” and 4.5” tangle nets compared to 8” gill net.– Long-term survival: tangle 95%; gill 50%.
• 2002 Experiments – Spring Chinook– 4.5” tangle net and 5.5” gill net.– Preliminary results:
• Immediate mortality: 4.5” 0.6%; 5.5” 1.1%• Long term survival: 4.5” 76%; 5.5” 57%
• 2002 commercial fishery intercepted 21,000 steelhead to harvest 24,000 spring chinook– WDFW 54 steelhead, distributed evenly
• Need precise, local estimates of recreational fishing mortality.
Regional Significance
• Addresses parts of RPA 107, 164, 165, 166, 167 particularly:– assess the effects of capture and release on the
spawning success of listed species – assess or improve estimates of incidental mortalities in
fisheries (selective or non-selective) significantly affecting ESUs addressed in RPA
– perform additional mortality rate studies in conjunction with the development of selective fisheries
– investigate weed-line or drop-net modifications for avoiding steelhead
Goal
Continue evaluating the effects of mark-selective fisheries on the post-release survival and spawning success of target and non-target species so that managers can provide harvest opportunities while continuing to protect weak stocks.
Study Locations
Objective 1
• Estimate the survival of adult winter steelhead captured and released from two sizes of tangle nets suitable for targeting spring chinook salmon.
• Estimate the catch efficiency of steelhead in each net type.
• Estimate the net depth range in which 90% of the steelhead are captured.
Methods – Objective 1
• Capture steelhead in tangle nets below Bonneville Dam (test) and in the adult collection facility (control).
• Note location of each fish in the net and net type.
• Collect biological information about each fish and revive as necessary.
• Tag with radiotags and release.• Track tag recoveries throughout Columbia
River Basin using stationary receivers.
Objective 2
• Compare the egg-to-fry survival of females captured and released from tangle nets fertilized with males captured and released from tangle nets to the egg-to-fry survival of fish not captured in the gears for spring chinook salmon and winter steelhead.
• On the Kalama River, compare the number of offspring produced per adult.
Methods – Objective 2
• Capture spring chinook and steelhead near the mouths of the Cowlitz and Kalama rivers using tangle nets. Tag and release all captured fish.
• At Cowlitz and Kalama hatcheries, recover tagged fish (test) and a comparable group of untagged fish (controls).
• Tagged males x tagged females; untagged males x untagged females.
• Compare egg-to-fry survival.
Methods – Objective 2
• Collect DNA samples from all tagged adults returning to the Kalama River trap.
• Collect DNA samples from outmigrating smolts.
• Estimate the production of smolts for each tagged adult, compare to production for untagged adults.
Objective 3
Estimate the long-term survival of spring chinook, fall chinook, and coho salmon captured and released during recreational fisheries.
Methods – Objective 3
• Below Bonneville Dam, capture spring chinook, coho, and fall chinook using typical sport fishing gears (test).
• Capture spring chinook, coho, and fall chinook in the adult collection facility at Bonneville Dam (controls).
• Collect biological information about each fish, tag and release (no revival).
• Estimate survival of each group relative to the controls at Bonneville Dam.
Application
• These results will be used by fishery managers to specify gear types allowed in each fishery.
• Estimates of post-release survival in recreational fishery will verify the precision of the number that is currently used.
• Estimates of survival will be used to model the impacts of each fishery on weak stocks.
• Estimates of post-release spawning success will indicate the effects capture and release may have beyond the tag recovery stage.
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