Modelling abundance and distribution of seabird by-catch in the Spanish Mediterranean longline fishery
[EN]: Seabird by-catch caused by longline fisheries is the most critical global threat to seabirds, mainly tubenose petrels. The Western Mediterranean is an important fishing area where the Spanish drifting longline operates. By-catch of these fisheries includes several resident and non-resident sea...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2010 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/144286 |
| Acceso en línea: | http://hdl.handle.net/10261/144286 |
| Access Level: | acceso abierto |
| Palabra clave: | Palangre Pesquerías sostenibles Conservation biology Biología de la conservación Aves marinas Longline Long-lived animals Marine bird Sustainable fisheries Animales de larga vida |
| Sumario: | [EN]: Seabird by-catch caused by longline fisheries is the most critical global threat to seabirds, mainly tubenose petrels. The Western Mediterranean is an important fishing area where the Spanish drifting longline operates. By-catch of these fisheries includes several resident and non-resident seabird species of different conservation concern. One of the main goals of seabird conservation is to disentangle the factors determining by-catch and to identify which management and conservation actions are necessary to mitigate this problem. In this paper, we modeled the effects of surface longline and its interaction with others fisheries on seabird by-catch. We used data recorded by onboard observers of the Spanish Institute of Oceanography (IEO) within the monitoring program for commercial longline fisheries from 2000 to 2009. We estimated a favourability function from logistic regression where the dependent variable was the presence or absence of seabird by-catch per set and the independent variables were those related to technical characteristics of the fishery, interactions with other fisheries, geographical location, and month. The interaction with other fisheries was estimated as the number of working and non-working days (weekend and official holidays), because the Spanish fishing legislation only allows longliners to operate in non-working days. We obtained a statistically significant favourability model with the following variables: traditional longline targeting swordfish, longline targeting albacore, number of hooks, latitude where the setting started, fisheries over continental shelf, October, and non-working days. The difference of the favourability function between working and non-working days provided a measure of the effect of non-working days on seabird by-catch. We concluded that the effects of the interaction with others fisheries on seabird by-catch are important, making non working days 48% more favourable than working days for increase seabird by-catch. The ecological and management implications are discussed. |
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