SUMMARY
The purpose of this paper is to investigate all available U.S. and Canadian observer and logbook data to detect trends in abundance for pelagic and large coastal shark species in the Northwest Atlantic. We found that it was very difficult to obtain long terms trends from a combined analysis of the U...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.576.2826 http://www.iccat.int/Documents/CVSP/CV054_2002/no_4/cv054041294.pdf |
| Summary: | The purpose of this paper is to investigate all available U.S. and Canadian observer and logbook data to detect trends in abundance for pelagic and large coastal shark species in the Northwest Atlantic. We found that it was very difficult to obtain long terms trends from a combined analysis of the U.S. and Canadian observer data sets because of very limited overlap among the datasets. We found that the most useful data set was the U.S. logbook data if it was analyzed using assumptions that were likely to be true. For example, we assumed only that if sharks were reported that the number caught was approximately correct, but not that sharks were always reported. Our results indicate that the hammerhead, white, and blue sharks may have undergone declines since 1986. The U.S. logbook data also suggests a decline in the thresher, mako, and tiger sharks. RÉSUMÉ Le présent document a pour but d=examiner toutes les données disponibles des carnets de pêche et des observateurs américains et canadiens pour rechercher la tendance de l=abondance des espèces de requins pélagiques et de grands requins côtiers dans l =Atlantique nord-ouest. Il s=est avéré très malaisé d =obtenir la tendance à long terme d =une analyse des |
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