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.