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  • 1
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    NOAA/National Marine Fisheries Service
    In:  http://aquaticcommons.org/id/eprint/2750 | 403 | 2011-09-29 18:24:34 | 2750 | United States National Marine Fisheries Service
    Publication Date: 2021-06-27
    Description: Greenland turbot (Reinhardtius hippoglossoides) is a commercially important flounder in both the North Atlantic and North Pacific Oceans. In the latter, its center of abundance is in the eastern Bering Sea and along the Aleutian Islands chain where its population is managed as a single stock. Harvest levels in this region of the North Pacific during the period 1970-81 were comparable with thosein the northwest and northeast Atlantic, with annual average catches of 53,000 metric tons (t). However, the catch in 1984 dropped sharply to 23,100 t, in partbecause of reduced quotas arising from concern over continued poor recruitment and declining catch-per-unit-effort.Recruitment failure was manifested in 1) the sharp decline in the catch rate of young flsh in annual research trawl surveys on the continental shelf of the eastern Bering Sea and 2) an increasing proportion of older and larger fish inthe commercial catch from the continental slope of both the eastern Bering Sea and Aleutian Islands. The cause ofthe decline in recruitment could not be clearly identifled.Greenland turbot of the Bering Sea-Aleutian Islands share certain distributional features with the North Atlantic form. There is an apparent bathymetric change in the size and age of fish, with younger animals occupying continentalshelf depths and the older individuals residing at depths of the continental slope. At shallow depths the young are exposed to temperature fluctuations, whereas older animals along the slope are exposed to relatively stable temperatures.A hypothesis is proposed for describing the temporal and spatial paths by which young animals reach the mature or spawning portion of the population. (PDF file contains 38 pages.)
    Keywords: Ecology ; Management ; Fisheries
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
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  • 2
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    NOAA/National Marine Fisheries Service
    In:  http://aquaticcommons.org/id/eprint/2701 | 403 | 2011-09-29 18:29:31 | 2701 | United States National Marine Fisheries Service
    Publication Date: 2021-06-27
    Description: The eastern Bering Sea is a major marine ecosystem containing some of the largest populations of groundfish, crabs, birds, and marine mammals in the world. Commercialcatches of groundfish in this region have averaged about 1.6 million tons (t) annually in 1970-86. This report describes the species and relative importance of species in the eastern Bering Sea groundfish complex, the environment in which they live, and the history of the fisheries and management during the years 1954 - 1985. Historical changes in abundance and the condition of the principal species at the end of this first 30 years of exploitation are also examined. Results suggest that the biomass of the groundfish complex is characterized by variability rather than stability. The most reliable data (1979 to 1985) suggests that the biomass of the complex fluctuated between 11.8 and 15.7 million t. Even greater variabilityis suggested by the less reliable data from earlier years. Because of its dominance in the complex and wide fluctuations in abundance, walleye pollock (Theragra chalcogramma) is primarily responsible for the major variations in abundance of the complex. After 30 yearsof exploitation, the complex was generally in excellent condition. (PDF file contains 100 pages.)
    Keywords: Management ; Ecology ; Fisheries
    Repository Name: AquaDocs
    Type: monograph
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  • 3
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    In:  http://aquaticcommons.org/id/eprint/9886 | 403 | 2012-08-20 12:39:05 | 9886 | United States National Marine Fisheries Service
    Publication Date: 2021-06-26
    Description: Yellowfin sole, Pleuronectes asper, is the second most abundant flatfish in the North Pacific Ocean and is most highly concentrated in the eastern Bering Sea. It has been a target species in the eastern Bering Sea since the mid-1950's, initially by foreign distant-water fisheries but more recently by U.S. fisheries. Annual commercial catches since 1959 have ranged from 42,000 to 554,000 metric tons (t). Yellowfin sole is a relatively small flatfish averaging about 26 cm in length and 200 g in weight in commercial catches. It is distributed from nearshore waters to depths of about 100 m in the eastern Bering Sea in summer, but moves to deeper water in winter to escape sea ice. Yellowfin sole is a benthopelagic feeder. It is a longlived species (〉20 years) with a correspondingly low natural mortality rate estimated at 0.12.After being overexploited during the early years of the fishery and suffering a substantial decline in stock abundance, the resource has recovered and is currently in excellent condition. The biomass during the 1980's may have been as high as, if not higher than, that at the beginning of the fishery. Based on results of demersal trawl surveys and two age structured models, the current exploitable biomass has been estimated to range between 1.9 and 2.6 million t. Appropriate harvest strategies were investigated under a range of possible recruitment levels. The recommended harvest level was calculated by multiplying the yield derived from the FOI harvest level (161 g at F = 0.14) hy an average recruitment value resulting in a commercial harvest of 276,900 t, or about 14% of the estimated exploitable biomass.
    Keywords: Biology ; Fisheries ; Management
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
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    Format: 1-18
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