Sablefish Management and Research
Fisheries for sablefish in Alaska are both federally and state managed. The majority of sablefish fisheries in Alaska are limited entry and are managed through quota shares. Federal fisheries occur along the outer coast in the Gulf of Alaska, along the Aleutian Islands and in the Bering Sea with the majority of the harvest from the central Gulf and in Southeast. State managed fisheries for sablefish occur in Southeast Alaska, Prince William Sound, Cook Inlet, and in the Aleutian Islands.
Sablefish in federal waters are managed by regions in order to distribute exploitation. The acceptable biological catch (ABC) is apportioned between these regions and then allocated between gear types. A stock assessment is performed annually for the federal fishery using an age-structured model; this assessment is reviewed by the North Pacific Management Council.
At the time the Federal Government began the IFQ program, the State established two minor fisheries in Cook Inlet and the Aleutian Islands, so that open-access fisheries were available to fishermen that were not allowed to participate in the IFQ program. These fisheries are managed using a Guideline Harvest Level (GHL), which is determined based on harvest history, fishery performance, and the federal survey for the area.
Three major state fisheries exist which are limited entry and are located in Prince William Sound, Chatham, and Clarence Strait. The Prince William Sound sablefish fishery is managed using a GHL and derived from the estimated area of sablefish habitat and a yield-per-unit-area model. For Clarence and Chatham Strait fisheries an annual harvest objective is set with regard to survey and fishery catch per unit effort and biological characteristics of the population. In addition, in Chatham Strait an annual stock assessment is performed which includes a mark-recapture estimate of the population abundance.
Sablefish are caught primarily with longline gear in Alaska; however, the Clarence Strait area has both a season for pot and longline gear. The Aleutian Islands state fishery allows longline, pot, jig, and hand troll gear, and one trawl vessel qualifies for the limited entry program in Prince William Sound. In federal waters, sablefish are primarily caught in directed fisheries on longline gear; however, an increasing trend toward pot gear exists due to whale depredation of sablefish on longline gear. In addition, sablefish are caught as bycatch in trawl fisheries.
The National Marine Fisheries Service (NMFS) and ADF&G conduct assessment surveys on sablefish in Alaskan waters. The NMFS conducts an annual longline survey and a triennial trawl survey in the Gulf of Alaska, and ADF&G performs annual longline surveys in Chatham and Clarence Strait. These surveys provide estimates of catch per unit effort, relative abundance, and biological data. In addition, tagging studies exist to study sablefish movement for federal, state, and Canadian waters. The ADF&G conducts an annual tagging survey in Chatham Strait as part of a mark-recapture study to estimate population abundance.
Further investigations into the migration of sablefish are being conducted in Alaska. The NMFS is working on a migration model that includes both federal and state waters. In addition, the ADF&G is conducting pilot studies to determine the feasibility of acoustic tagging of sablefish in Chatham Strait.
In addition, research is being conducted on sperm whale interactions with the sablefish longline fisheries. Researchers are determining ways to reduce or eliminate whale interactions and how to quantify whale depredation rates.