2016 Lower Columbia River Fall Seine Fishery Monitoring Report

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Published: January 2017

Pages: 19

Publication number: FPT 17-01

Author(s): Ann E. Stephenson

Executive Summary

The 2016 commercial seine fishery was one component of the overall non-Indian commercial fisheries in the lower Columbia River downstream of Bonneville Dam. The fishery was scheduled for twenty periods (or days) between August 22nd and September 30th. The fishery was actively fished from September 6th through September 30th. A total of four seine permits were issued, two for purse seines and two for beach seines. The beach seiners were allowed to fish in non-Indian commercial fishing Zones 2 and 3, while the purse seiners could fish in Zones 1 and 3 (Figure 1). The restrictions on the fishing location were an effort to help the Washington Department of Fish and Wildlife (WDFW) and Oregon Department of Fish and Wildlife (ODFW) collect data on the fish stock composition for salmonids from areas where limited data had been collected in the previous two years of seine fishing, in an effort to more fully model mainstem commercial fisheries throughout the lower Columbia River.

Overall, 4,103 steelhead, fall Chinook and Coho salmon were caught, either kept or released, in the 2016 seine fishery. 4,055 salmonids were caught in purse seines and 48 in beach seines. The majority of those fish were fall Chinook salmon (70%), followed by Coho salmon (23%) and steelhead (7%). The majority of the fish caught and kept by both gear types were adult fish. Ninety percent of the fall Chinook salmon were adults and 83% of the Coho salmon were adults. The immediate mortality rate for this fishery was less than 0.3% of the total number of fall Chinook salmon, Coho salmon and steelhead caught.

The individual fishing quota (IFQ) for each purse seine was 750 kept adult fall Chinook salmon, 600 kept adult Coho salmon, or 230 handled steelhead, whichever species-specific quota was met first. The two purse seiners kept a total of 1,113 fall Chinook salmon, including 728 adipose fin-clipped (marked) adults, 93 marked jacks, 272 unmarked adults, and 20 unmarked jacks. Of the 1,500 adult fall Chinook available for harvest, a total of 1,000 adults, both marked and unmarked, were harvested by the two purse seiners, representing 67% of their combined IFQs. A total of 469 adult Coho salmon were retained, all marked, which represented 39% of the Coho salmon IFQ for purse seines. A total of 295 steelhead were handled in the purse seines (16 unmarked A-run, 104 marked A-run, 31 unmarked B-run and 144 marked B-run), which was 64% of the allowable steelhead handle for the purse seines combined. The overall mark rates for adult fall Chinook salmon caught in the purse seines was 30% and the mark rate for adult Coho salmon was 63%. The overall mark rate for steelhead handled by the purse seines was 84%.

The IFQ for each beach seine was 600 kept adult fall Chinook salmon, 400 kept Coho salmon, or 320 handled steelhead, whichever quota was met first. The beach seiners fished a total of six days and caught very few fish overall. Some of their time entailed exploring new areas and experiencing equipment difficulties. Overall, two fall Chinook salmon (one marked jack and one unmarked adult) and 39 marked Coho salmon (13 adult and 26 jacks) were harvested by the beach seiners. Five unmarked Coho salmon and 2 steelhead (one unmarked A-run and one marked B-run) were released.

One of the objectives of the fishery was to determine the steelhead to adult fall Chinook salmon ratios by gear type and fishing zone. The following ratios are for adult fish from the purse seines: steelhead to marked fall Chinook salmon 2:5; steelhead to unmarked fall Chinook 1:6; and steelhead to all fall Chinook 1:8. The beach seine catch was not substantial enough to allow for meaningful comparisons, with only one adult fall Chinook caught and two steelhead released.

Some of all three of the objectives for this fishery were addressed in 2016, including the collection of steelhead to fall Chinook salmon ratios by gear type and fishing zone, the collection of CWT data from the landed catch to determine fall Chinook salmon stock composition, and the collection of immediate mortality rates for these two gear types. Challenges in 2016 included the lack of purse seine fishing in Zone 1, where catch data are still needed, and the low effort and catch from the beach seines.