Presentation on theme: "Evaluate recreational and commercial mark-selective fisheries. (35018) Geraldine Vander Haegen, WDFW Charmane Ashbrook, WDFW Chris Peery, U. Idaho Annette."— Presentation transcript:
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.
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.