![]() The model is sex-specific because males and females have different growth and maturity rates, and females attain larger maximum sizes. The Alaska Fisheries Science Center models the entire federally managed Alaska sablefish fishery as one population, integrating data from the Bering Sea, Aleutian Islands, and the Gulf of Alaska. However, some genetic work is currently underway to test this hypothesis. There are four management areas in the Gulf of Alaska: Western, Central, West Yakutat, and East Yakutat/Southeast Outside (SEO) and two management areas in the Bering Sea/Aleutian Islands (BSAI): the eastern Bering Sea (EBS) and the Aleutian Islands region.īecause juveniles appear to migrate all throughout Alaskan waters (see map above), little fine-scale genetic structure is expected. Sablefish are managed by discrete regions to distribute exploitation throughout their wide geographical range. Sablefish are assessed as a single population in Federal waters off Alaska because northern sablefish are highly migratory for at least part of their life. Mixing of the two populations occurs off southwest Vancouver Island and northwest Washington. A northern population inhabits Alaska and northern British Columbia waters while a southern population inhabits southern British Columbia, Washington, Oregon, and California waters. Sablefish form two populations based on differences in growth rate, size at maturity, and tagging studies. Juvenile sablefish are eaten by adult coho and chinook salmon. Yearling sablefish primarily feed on euphausiids. After their second summer, they begin moving offshore, typically reaching their adult habitat, the upper continental slope, at 4 to 5 years.Īdult sablefish are opportunistic feeders, preying on fish (including pollock, eulachon, capelin, herring, sandlance, and Pacific cod), squid, euphausiids, and jellyfish. Near the end of the first summer, pelagic juveniles less than 20 cm drift inshore and spend the winter and following summer in inshore waters, reaching 30-40 cm by the end of their second summer. During surveys of the outer continental shelf, most young-of-the-year sablefish were caught in the central and eastern Gulf of Alaska. The average spawning date, based on otolith analysis, is March 30. Eggs develop at depth and larvae develop near the surface up to 180 miles offshore. Spawning occurs pelagically at depths of 300-500 m near the edges of the continental slope. Fifty percent of males are mature at 57 cm (5 years) and fifty percent of females are mature at 69 cm (6.5 years). In the Gulf of Alaska, adult sablefish may reach a maximum length and weight of 88 cm and 6.8 kg respectively for males and 110 cm and 14 kg for females. However, because sablefish are difficult to age, these ages are approximate. In Southeast Alaska inside waters the maximum age is 65 years (from Alaska Department of Fish and Game Survey data, 1988-2001). The maximum reported age in Alaska is 94 years. ![]() Sablefish are a long-lived species with fish over age 40 years commonly found in commercial samples. What Do We Know About Sablefish in Alaska? Together this information is used to estimate population size and determine catch quotas for this commercially important fish species in Alaska. Although in terms of landed weight, sablefish support a relatively small fishery, its high price per pound makes it a nearly 100 million dollar fishery, third in value to walleye pollock and Pacific cod. The relative abundance indices produced from this survey are combined with age, length, and fishery data to estimate absolute abundance of several major groundfish species. A unique aspect of this survey is that the charter vessel retains most of the catch after the scientific data are recorded, which funds the survey operations. The survey is conducted using a chartered fishing vessel capable of catching and processing the catch at sea which allows the vessel to stay at sea for multiple weeks between port calls. The survey lasts three months and each day nearly nine miles of hook and line gear is fished on the ocean floor at depths from 200-1000 meters. We conduct an annual longline survey to learn more about sablefish and major groundfish species in the Bering Sea, Aleutian Islands, and Gulf of Alaska. Through our own research and collaborations with the Alaska Department of Fish and Game, we collect a wealth of information on sablefish each year including information on their life span and growth and where they spawn. Sablefish observed from a manned submersible were found on or within 1 m of the bottom. Adult sablefish are found along the continental slope, shelf gullies, and in deep fjords commonly in depths between 366 m to 914 m, although they have been found in depths of less than 183 m (100 fm) to over 1829 m (1000 fm).
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