Fishery by-catches of marine mammals in Galician waters: results from on-board observations and an interview survey of fishermen
16 páginas, 9 figuras, 3 tablas Rates of cetacean by-catch were investigated in Galician waters (NW Spain) using a combination of observer trips on fishing vessels, a carcase recovery scheme and an interview survey of fishermen, carried out over two years (1998–1999). All these data sources are susp...
| Published in: | Biological Conservation |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Elsevier
2003
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10261/53800 https://doi.org/10.1016/S0006-3207(02)00244-6 |
| Summary: | 16 páginas, 9 figuras, 3 tablas Rates of cetacean by-catch were investigated in Galician waters (NW Spain) using a combination of observer trips on fishing vessels, a carcase recovery scheme and an interview survey of fishermen, carried out over two years (1998–1999). All these data sources are suspected of underestimating by-catch due to the sample of co-operating fishermen being, necessarily, self-selecting. No by-catches were seen during observer trips, although not all sectors of the fishery could be covered. The carcass recovery scheme yielded seventeen cetacean carcases over two years, which compares to around 35 by-caught cetaceans recorded annually by the Galician strandings network. Analysis of interview data suggested that around 200 cetaceans might be caught annually in inshore waters and around 1500 in offshore waters. Confidence limits were wide for all estimates. The highest by-catch rates were estimated for gillnets and offshore trawling. The majority of by-catches are small dolphins, probably mainly Delphinus delphis. Smaller numbers of Tursiops truncatus and Globicephala melas are also reported. Comparing the interview estimates of by-catch rates with minimum estimates of population size, it is suggested that by-catches of D. delphis and T. truncatus may be unsustainably high and that routine monitoring of fishery by-catches in Galician fisheries is required This study was supported by the Commission of the European Communities under the auspices of two projects, ‘‘Impact of fisheries on small cetaceans in coastal waters of Northwest Spain and Scotland’’ (DG Fisheries Study 97/089) and ‘‘Development of software to estimate unreported or misreported catch and effort data and to apply fishery management models’’ (DG Fisheries Study 97/170). Peer reviewed |
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