Connecting Independent Research Surveys of Bering Sea Salmon Populations to Chum Salmon Bycatch in Bering Sea Groundfish Fisheries
September 18, 2018
Although chum salmon bycatch has historically remained at low levels relative to their biomass in the Bering Sea, recent increases in chum salmon bycatch have generated concern over bycatch impacts on Alaskan salmon stocks and the effectiveness of regulatory measures used to control bycatch in the groundfish fisheries. Member nations of the North Pacific Anadromous Fish Commission (Canada, Japan, Russia, South Korea, and the United States) developed the Bering-Aleutian Salmon International Survey (BASIS) in 2002 as an international cooperative research program designed to address concerns over the distribution, growth, and survival of salmon in the Bering Sea. By connecting information collected during BASIS research surveys to bycatch, we identify how size, foraging behavior, and foraging hotspots of chum salmon are important controlling factors of bycatch and bycatch potential in Bering Sea groundfish fisheries.
The Bering Sea walleye pollock (Theragra chalcogramma) fishery is the largest commercial fishery by weight within the United States. The walleye pollock fishery occurs during two distinct periods throughout the year, with the ‘A’ season fishery during late January to the end of March and the ‘B’ season fishery from mid-June to the end of October. The relative bycatch during the fishery is low, averaging approximately 1.2% of total removals by weight, compared to the estimated bycatch of 11% for all Alaska fisheries and the average nationwide bycatch estimates that approach 22% by weight. Of the 1.2% bycatch by weight in the Bering Sea pollock fishery, 24% is attributed to jellyfish while 64% consists of other quota-managed target groundfish species. A smaller portion consists of Pacific salmon (Oncorhynchus spp.)—mainly chum (O. keta) and Chinook salmon (O. tshawytscha). Chum salmon are primarily captured during the B season and Chinook salmon during both the A and B seasons.