التفاصيل البيبلوغرافية
| العنوان: |
From Sunrise to Sunset in the California Drift Gillnet Fishery: An Examination of the Effects of Time and Area Closures on the Catch and Catch Rates of Pelagic Species. |
| المؤلفون: |
URBISCI, LAURA C.1 lurbisci@gmail.com, STOHS, STEPHEN M.2, PINER, KEVIN R.2 |
| المصدر: |
Marine Fisheries Review. 2016, Vol. 78 Issue 3/4, p1-11. 11p. |
| مصطلحات موضوعية: |
*STANDARDIZATION, GILLNETTING, PELAGIC fishes, CONSERVATION biology, FISHING catch effort |
| مصطلحات جغرافية: |
CALIFORNIA |
| مستخلص: |
The California drift gillnet fleet has operated off the U.S. west coast since it developed in the late 1970's. At its full extent, fishing effort ranged from the Southern California Bight north to Oregon. The fishery initially targeted pelagic sharks (family Alopiidae), but shifted targets in the mid-1980's to swordfish, Xiphias gladius, due to the species' higher value and to the regulatory changes which created an economic advantage for targeting swordfish compared to thresher shark, Alopias vulpinas. Consequently the number of participants in the once-small fleet substantially increased. Conservation concerns over the entanglement of nontarget species, including sharks, sea turtles (family Dermochelyidae and Cheloniidae), and marine mammals, led to the enactment of a series of time and area closures over a period of 19 years to reduce the bycatch of those species. As a result, the fishery declined dramatically. This paper analyzes catch and effort data for the fishery to determine the effects of these management measures on targeted pelagic sharks and swordfish catch per unit of effort (CPUE). Unlike traditional catch-rate analysis, which seeks to standardize fishing effort heterogeneity to produce a measure of relative stock abundance, our analysis uses a linear regression of set-level catch counts on time and area combinations where fishing occurred over the full period for which data is available to estimate the effects of time and area closures on fishery catch rates while controlling for population abundance trends. Resampling methods are used to quantify uncertainty in the estimates. The analysis documents reduced common thresher and shortfin mako shark, Isurus oxyrinchus, CPUE resulting from effort shifting out of higher to lower catch rate areas. Before the 2001 establishment of the Pacific Leatherback Conservation Area (PLCA) closure which eliminated most effort in the fishery north of Pt. Conception, the fishery operated from the Mexican territorial water border northward to Oregon. The cumulative effect of all enacted time and area closures was to concentrate fishing effort within the Southern California Bight, likely contributing to a decline in vessel participation. The socioeconomic impacts on the operation of the fishery and on the usefulness of drift gillnet CPUE data for stock assessments are discussed. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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