Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities
We analysed and compared the diet of Audouin´s gulls Larus audouinii between their two largest breeding sites in the world: the Ebro Delta and the Chafarinas Islands (western Mediterranean). These two localities showed marked differences in the features of the commercial fishing fleet: in the Ebro D...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2002 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/32305 |
| Acceso en línea: | https://hdl.handle.net/2445/32305 |
| Access Level: | acceso abierto |
| Palabra clave: | Gavines Alimentació animal Indústria pesquera Chafarinas (Espanya) Ebre, Delta de l' (Catalunya) Gulls Animal feeding Fishing industry Chafarinas Islands (Spain) Ebro River Delta (Catalonia) |
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Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activitiesPedrocchi Rius, VittorioOro, DanielGonzález-Solís, JacobRuiz Gabriel, XavierJover Armengol, Lluís deGavinesAlimentació animalIndústria pesqueraChafarinas (Espanya)Ebre, Delta de l' (Catalunya)GullsAnimal feedingFishing industryChafarinas Islands (Spain)Ebro River Delta (Catalonia)We analysed and compared the diet of Audouin´s gulls Larus audouinii between their two largest breeding sites in the world: the Ebro Delta and the Chafarinas Islands (western Mediterranean). These two localities showed marked differences in the features of the commercial fishing fleet: in the Ebro Delta area a large fishing fleet produced large amounts of discards, while in the Chafarinas the fleet discarded smaller amounts of fish and marine invertebrates, due to the smaller number of vessels. It is also likely that the percentage of discards from total catches is also lower around the Chafarinas than at the Ebro Delta. We distinguished two types of fishing to compare diet compositions: diurnal (only trawling activity) and diurnal and nocturnal (trawling and purse-seine activity, respectively). We also differentiated regurgitates from young nestlings (up to 20 days old) and from older nestlings or adult birds. At the two localities, fish was the main food of Audouin´s gulls, with epipelagic prey (mainly clupeoids) being more important when both diurnal and nocturnal fisheries were operating. This confirms that epipelagic prey either caught actively by the gulls or linked to fisheries was particularly important in the feeding habits of Audouin´s gulls. Nevertheless, differences between the two colonies appear mainly when only trawlers operated: while at the Ebro Delta gulls showed higher consumption of benthic-mesopelagic prey (probably linked to a higher trawler discard availability), gulls from the Chafarinas Islands consumed higher biomass of epipelagic prey probably caught actively at night. When both fleets operated around the two colonies, the average biomass of prey in a regurgitate of younger chicks was significantly higher at the Ebro Delta than at Chafarinas, and the opposite trend was recorded for older nestlings and adults. Niche width was broader in Chafarinas than in the Ebro Delta for both age classes and for any fishing fleet schedule, suggesting again that the exploitation of discards was higher at the Ebro Delta than at the Chafarinas, where gulls showed a more varied diet. Despite the fact that availability of discards was probably higher at the Ebro Delta than at Chafarinas, the per capita availability was not so different at both localities due to the increasing seabird community population at the Ebro Delta, which ca. doubled that at Chafarinas in the last decade.Consejo Superior de Investigaciones Científicas (CSIC)2002info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/32305Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció del document publicat a: http://dx.doi.org/10.3989/scimar.2002.66n3313Scientia Marina, 2002, vol. 66, num. 3, p. 313-320http://dx.doi.org/10.3989/scimar.2002.66n3313cc-by-nc (c) Consejo Superior de Investigaciones Científicas (CSIC), 2002http://creativecommons.org/licenses/by-nc/3.0/esinfo:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/323052026-05-27T06:46:51Z |
| dc.title.none.fl_str_mv |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| title |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| spellingShingle |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities Pedrocchi Rius, Vittorio Gavines Alimentació animal Indústria pesquera Chafarinas (Espanya) Ebre, Delta de l' (Catalunya) Gulls Animal feeding Fishing industry Chafarinas Islands (Spain) Ebro River Delta (Catalonia) |
| title_short |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| title_full |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| title_fullStr |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| title_full_unstemmed |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| title_sort |
Differences in diet between the two largest breeding colonies of Audouin's gulls: the effects of fishery activities |
| dc.creator.none.fl_str_mv |
Pedrocchi Rius, Vittorio Oro, Daniel González-Solís, Jacob Ruiz Gabriel, Xavier Jover Armengol, Lluís de |
| author |
Pedrocchi Rius, Vittorio |
| author_facet |
Pedrocchi Rius, Vittorio Oro, Daniel González-Solís, Jacob Ruiz Gabriel, Xavier Jover Armengol, Lluís de |
| author_role |
author |
| author2 |
Oro, Daniel González-Solís, Jacob Ruiz Gabriel, Xavier Jover Armengol, Lluís de |
| author2_role |
author author author author |
| dc.subject.none.fl_str_mv |
Gavines Alimentació animal Indústria pesquera Chafarinas (Espanya) Ebre, Delta de l' (Catalunya) Gulls Animal feeding Fishing industry Chafarinas Islands (Spain) Ebro River Delta (Catalonia) |
| topic |
Gavines Alimentació animal Indústria pesquera Chafarinas (Espanya) Ebre, Delta de l' (Catalunya) Gulls Animal feeding Fishing industry Chafarinas Islands (Spain) Ebro River Delta (Catalonia) |
| description |
We analysed and compared the diet of Audouin´s gulls Larus audouinii between their two largest breeding sites in the world: the Ebro Delta and the Chafarinas Islands (western Mediterranean). These two localities showed marked differences in the features of the commercial fishing fleet: in the Ebro Delta area a large fishing fleet produced large amounts of discards, while in the Chafarinas the fleet discarded smaller amounts of fish and marine invertebrates, due to the smaller number of vessels. It is also likely that the percentage of discards from total catches is also lower around the Chafarinas than at the Ebro Delta. We distinguished two types of fishing to compare diet compositions: diurnal (only trawling activity) and diurnal and nocturnal (trawling and purse-seine activity, respectively). We also differentiated regurgitates from young nestlings (up to 20 days old) and from older nestlings or adult birds. At the two localities, fish was the main food of Audouin´s gulls, with epipelagic prey (mainly clupeoids) being more important when both diurnal and nocturnal fisheries were operating. This confirms that epipelagic prey either caught actively by the gulls or linked to fisheries was particularly important in the feeding habits of Audouin´s gulls. Nevertheless, differences between the two colonies appear mainly when only trawlers operated: while at the Ebro Delta gulls showed higher consumption of benthic-mesopelagic prey (probably linked to a higher trawler discard availability), gulls from the Chafarinas Islands consumed higher biomass of epipelagic prey probably caught actively at night. When both fleets operated around the two colonies, the average biomass of prey in a regurgitate of younger chicks was significantly higher at the Ebro Delta than at Chafarinas, and the opposite trend was recorded for older nestlings and adults. Niche width was broader in Chafarinas than in the Ebro Delta for both age classes and for any fishing fleet schedule, suggesting again that the exploitation of discards was higher at the Ebro Delta than at the Chafarinas, where gulls showed a more varied diet. Despite the fact that availability of discards was probably higher at the Ebro Delta than at Chafarinas, the per capita availability was not so different at both localities due to the increasing seabird community population at the Ebro Delta, which ca. doubled that at Chafarinas in the last decade. |
| publishDate |
2002 |
| dc.date.none.fl_str_mv |
2002 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
| format |
article |
| status_str |
publishedVersion |
| dc.identifier.none.fl_str_mv |
https://hdl.handle.net/2445/32305 |
| url |
https://hdl.handle.net/2445/32305 |
| dc.language.none.fl_str_mv |
Inglés |
| language_invalid_str_mv |
Inglés |
| dc.relation.none.fl_str_mv |
Reproducció del document publicat a: http://dx.doi.org/10.3989/scimar.2002.66n3313 Scientia Marina, 2002, vol. 66, num. 3, p. 313-320 http://dx.doi.org/10.3989/scimar.2002.66n3313 |
| dc.rights.none.fl_str_mv |
cc-by-nc (c) Consejo Superior de Investigaciones Científicas (CSIC), 2002 http://creativecommons.org/licenses/by-nc/3.0/es info:eu-repo/semantics/openAccess |
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cc-by-nc (c) Consejo Superior de Investigaciones Científicas (CSIC), 2002 http://creativecommons.org/licenses/by-nc/3.0/es |
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openAccess |
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application/pdf |
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Consejo Superior de Investigaciones Científicas (CSIC) |
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Consejo Superior de Investigaciones Científicas (CSIC) |
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Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals) reponame:Dipòsit Digital de la UB instname:Universidad de Barcelona |
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Universidad de Barcelona |
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Dipòsit Digital de la UB |
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Dipòsit Digital de la UB |
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