The Commercial Size Limit for the Pacific Halibut Fishery Off Alaska and Its Relationship to Observer-derived Estimates of At-sea Discard PDF Download
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Author: Jennifer A. Cahalan
Publisher:
ISBN:
Category : Fishery discards
Languages : en
Pages : 42
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Book Description
Author: Jennifer A. Cahalan
Publisher:
ISBN:
Category : Fishery discards
Languages : en
Pages : 42
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Book Description
Author:
Publisher:
ISBN:
Category : Administrative law
Languages : en
Pages : 1590
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 842
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Book Description
Author:
Publisher:
ISBN:
Category : Halibut fisheries
Languages : en
Pages : 32
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Book Description
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309174406
Category : Technology & Engineering
Languages : en
Pages : 194
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Book Description
Ocean harvests have plateaued worldwide and many important commercial stocks have been depleted. This has caused great concern among scientists, fishery managers, the fishing community, and the public. This book evaluates the major models used for estimating the size and structure of marine fish populations (stock assessments) and changes in populations over time. It demonstrates how problems that may occur in fisheries dataâ€"for example underreporting or changes in the likelihood that fish can be caught with a given type of gearâ€"can seriously degrade the quality of stock assessments. The volume makes recommendations for means to improve stock assessments and their use in fishery management.
Author: International Pacific Halibut Commission
Publisher:
ISBN:
Category : Halibut fisheries
Languages : en
Pages : 88
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Book Description
Author: Kieran Kelleher
Publisher: Food & Agriculture Org.
ISBN: 9789251052891
Category : Business & Economics
Languages : en
Pages : 156
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Book Description
This publication gives an updated review of the quantity of discards in the world's marine fisheries, using information from a broad range of fisheries in all continents. A number of policy issues are discussed including a 'no discards' approach to fisheries management, the need for balance between bycatch reduction and bycatch utilisation initiatives, and concerns arising from incidental catches of marine mammals, birds and reptiles. The report also highlights the need for more robust methods of estimating discards, and the development of bycatch management plans.
Author: Ray Hilborn
Publisher:
ISBN:
Category : Pacific halibut
Languages : en
Pages : 48
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Book Description
In 1980 and 1981, more than 68,000 juvenile halibut were tagged in the Gulf of Alaska and Southeast Alaska in an effort to obtain estimates of movements of juvenile halibut. In this paper we develop a maximum likelihood method for estimating the movement between International Pacific Halibut Commission (IPHC) regulatory Areas 3B, 3A, 2C, 2B and 2A. In addition to the movement rates, we also estimate the sizespecific natural mortality, tagging mortality and size selectivity for commercial gear in Areas 3B and 3A. We found that all of these parameters could be estimated with low confounding, and that the predicted recovery pattern of tags conforms closely to the observed recoveries. The best fitting model estimates that there are substantial southerly movements of juvenile halibut; for example, we estimate that 17% of fish tagged in 3B would recruit as adults to 2B, and that 25% of fish tagged in 3A would recruit as adults to 2B. Further improvements in the analysis could include smaller spatial scale of analysis, and combining tagging analysis with catch-at-age data.
Author: International Pacific Halibut Commission
Publisher:
ISBN:
Category : Fisheries
Languages : en
Pages : 48
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Book Description
Author: William G. Clark
Publisher:
ISBN:
Category : Fishery management
Languages : en
Pages : 40
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Book Description
Intrinsic growth parameters of female and male halibut, and the length-specific selectivity of the commercial setline fishery, were estimated by fitting a simple model to catch composition data collected in Areas 2B and 3A in 1990 and 1991. Area-specific schedules of female maturity as a function of length were estimated using data collected during the 1980s. Yield per recruit and spawning biomass per recruit of halibut in Area 2B and 3A were calculated using the new estimates of growth, selectivity, and maturity. The results showed the current 32-inch commercial size limit to be appropriate. (At time of publication in mid-1995, it is clear that halibut life history parameters have changed considerably since 1990. The size limit is therefore being reviewed again.).
