Solutions to seabird bycatch in Alaska's demersal longline fisheries

Melvin EF, Parrish JK, Dietrich KS, Hamel OS (2001) Solutions to seabird bycatch in Alaska’s demersal longline fisheries. Washington Sea Grant Program., Seattle, Washington

The incidental mortality of seabirds in longline fisheries is a serious conservation issue worldwide. In Alaska 10,000 to 27,000 seabirds are hooked each year. Most (75% of total number) are northern fulmars and gulls. However, regulatory and conservation attention is focused on bycatch of the endangered short-tailed albatross. Under the U.S. Fish and Wildlife Service’s Biological Opinion, takes exceeding 6 short-tailed albatross within a 2-year period (4 in the groundfish fishery and 2 in the Pacific halibut fishery) would trigger an Endangered Species Act (ESA) Section 7 consultation and could interrupt or close Alaska's $300 million (ex-vessel value) demersal longline fishery. The Biological Opinion requires that mitigation devices be used in the fishery and that research be conducted to test their effectiveness. Our research program stems from this imperative.

This research program compared seabird bycatch mitigation strategies over 2 years (1999 and 2000) in 2 major Alaska demersal longline fisheries: the Gulf of Alaska / Aleutian Island Individual Fishing Quota (IFQ) fishery for sablefish and halibut (referred to as the sablefish fishery) and the Bering Sea catcher-processor longline fishery for Pacific cod (referred to as the cod fishery). We conducted tests over two years to account for inter-annual variation and allow for improvement and innovation. A key feature of this program was an industry-agency-academic collaboration to identify possible deterrents and test them on active fishing vessels under typical fishing conditions.

We report the results of experimentally rigorous tests of seabird bycatch deterrents on the local abundance, attack rate, and hooking rate of seabirds in both fisheries. Based on our results, we recommend a suite of bycatch mitigation measures.

Our goal was to identify mitigation devices that significantly reduced seabird bycatch with no loss of target catch or increase in the bycatch of other organisms. Control sets with no deterrent established a baseline and allowed exploration of seabird interaction with longline gear as a function of temporal and spatial variation, physical factors such as wind and sea state, and fishery practices. Deterrents tested were identified by fishers in an adhoc committee process and included a mix of bird scaring strategies and techniques designed to minimize the time baited hooks are at or near the surface. See table "Deterrents by Year".

Participating vessels were recruited in cooperation with the Fishing Vessel Owners Association and the North Pacific Longline Association. Data were collected by specially trained National Marine Fisheries Service (NMFS) certified observers.