Bycatch and release of pelagic megafauna in industrial trawler fisheries off Northwest Africa

Zeeberg, J.J.; Corten, A.; Graaf, Erik de

doi:10.1016/j.fishres.2006.01.012

Cited by 100 publications

(94 citation statements)

References 12 publications

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“…With the resumption of both industrial and artisanal fishing in the area, however, (Zeeberg et al 2006), the risk of accidental entanglement has returned in force. Although no deaths have been directly linked to fishery interactions, there is concern that seals may fall victim to entanglement in the future (Anonymous 1990, González et al 2002.…”

Section: Discussionmentioning

confidence: 99%

Assessing accidental entanglement as a threat to the Mediterranean monk seal Monachus monachus

Karamanlidis¹,

Androukaki²,

Adamantopoulou³

et al. 2008

Endang. Species Res.

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The Mediterranean monk seal Monachus monachus is the most endangered seal in the world with < 600 ind. currently surviving. The species faces a number of threats to its survival: accidental entanglement has been identified as one of the most important amongst them. Here we made the first attempt to systematically describe the nature of this threat and assess its impact on Mediterranean monk seal populations. We based our study on information from an extensive literature review, questionnaires carried out in various locations in Greece and necropsies performed in Greece and in the Madeira Islands, Portugal. Our results indicate that accidental entanglement has been, and still is, a major threat to the species in its main distribution area in the northeastern Mediterranean, and that this threat may increase throughout the seal's range. Accidental entanglement occurs mainly with fishing nets, and affects mostly sub-adult seals. Short-term conservation actions should include the identification of critical pupping sites and their protection through the establishment and enforcement of protective measures. A long-term course of action will require detailed knowledge of the causes of accidental entanglement of Mediterranean monk seals in fishing gear.KEY WORDS: Endangered species · Mediterranean monk seal · Accidental entanglement · Conservation · Seal-fishery interactions · Greece · Madeira

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Section: Discussionmentioning

confidence: 99%

Assessing accidental entanglement as a threat to the Mediterranean monk seal Monachus monachus

Karamanlidis¹,

Androukaki²,

Adamantopoulou³

et al. 2008

Endang. Species Res.

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“…Well-designed observer programmes on fishing vessels can yield useful bycatch estimates of small cetaceans per unit of effort (e.g. Couperus, 1997;Zeeberg et al, 2006) but assessments should be regularly updated. Other potential threats, including coastal habitat encroachment such as aquaculture development (Watson-Capps and Mann, 2005), pollution (e.g.…”

Section: Discussionmentioning

confidence: 99%

Live-captures of common bottlenose dolphins Tursiops truncatus and unassessed bycatch in Cuban waters: evidence of sustainability found wanting

Waerebeek¹,

Sequeira²,

Williamson³

et al. 2006

Lat. Am. J. Aquat. Mamm.

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ABSTRACT:In the period 1986-2004, 238 common bottlenose dolphins Tursiops truncatus were exported from Cuba, as shown by UNEP/WCMC data, more than 60% of these to facilities in Latin America and the Caribbean, some 32% to Europe and the rest to Canada and Israel. There is a very significant increase in exported numbers, reaching 28 individuals per annum in 2002. It is unclear how many T. truncatus have been used in domestic dolphinaria. A review of available information did not identify evidence to corroborate hypotheses that: (i) T. truncatus off Sabana-Camagüey Archipelago (where removals occur) does not show population structure; and (ii) virtually no bycatches occur in Cuban waters. Here it is argued that, considering Cuba's fully developed marine fisheries, some level of mortality from bycatch is inevitable. Other potential threats are also identified. Global phylogenetics research of T. truncatus is revealing unexpected and more complex, stock structures, in inshore (coastal) forms within relatively small areas. In Cuba, low mean group sizes (less than 10) suggest that one or more coastal stock(s) are exploited. Sex distribution of measured specimens suggest a significant bias towards extraction of females. It is concluded that sustainability of harvest levels of Cuban T. truncatus cannot be evaluated until abundance estimates become available and population structure is verified by molecular genetic methods. Pérez-Cao (2004) indicated that available density estimates should not be used to determine [safe] catch quotas. The authors strongly recommend that international trade of T. truncatus from Cuba ceases until no-detriment can be authenticated and that more research be developed. Similar arguments may be applicable to other unassessed but exploited populations in the Wider Caribbean. RESUMEN:En el período 1986-2004, según datos obtenidos de PNUMA/WCMC, 238 delfines mular común Tursiops truncatus fueron exportados de Cuba; más del 60% de éstos hacia acuarios en América Latina y el Caribe, unos 32% a Europa y el resto hacia Canadá e Israel. Se distingue un aumento muy significativo en los números exportados, hasta 28 individuos per annum (en 2002). No hay información sobre el número de T. truncatus usados en acuarios domésticos en Cuba. Tras una revisión de la información disponible, no se encontraron evidencias para corroborar las hipótesis sugeridas que: (i) T. truncatus en el Archipiélago de Sabana-Camagüey (donde ocurre la explotación) no se presenta estructura de población y (ii) que virtualmente no ocurre ninguna captura accidental. Argumentamos que, considerando una pesquería marina plenamente desarrollada en Cuba, es inevitable algún nivel de capturas accidentales, y se identifica otras posibles amenazas. La investigación filogenética en T. truncatus, a nivel global, revela inesperada estructura o estructuras de stocks más complejas en la forma costera. Grupos de menor tamaño (menos de 10 indivíduos) sugieren que uno (o más) stocks costeros son explotados en Cuba. Distribución de frecuencia de sex...

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“…Although, pelagic sharks have been reported as bycatch on trawl fisheries (e.g. Zeeberg et al 2006), and tuna purse seines (for example Amandè et al 2011) from other seas, in the Spanish trawl and purse seine Mediterranean fisheries it is an unusual bycatch. For example, Abad et al (2007) did not report pelagic sharks as bycatch from trawl fisheries Alboran Sea, similarly Fromentin and Farrugio (2005) did not report any pelagic shark as bycatch from tuna purse seine fisheries from Mediterranean Sea.…”

Section: Methodsmentioning

confidence: 98%

Assessing the influence of the atmospheric oscillations on pelagic and highly migratory sharks bycatches from Spanish Mediterranean Sea, a meta-analytic approach

Báez¹

2015

analesbio

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Evaluación de la influencia de las oscilaciones atmosféricas sobre las capturas accesorias de tiburones pelágicos y altamente migratorios desde el Mediterráneo español, un enfoque metaanalíticoEl objetivo principal del presente estudio fue analizar el efecto de las oscilaciones atmosféricas sobre los patrones de descarga de los tiburones pelágicos capturados de forma accesoria en palangre de superficie (fundamentalmente tintoreras, marrajos, y tiburones zorros) desde el Mediterráneo español, utilizando un enfoque meta-analítico. El objetivo final es conocer la respuesta de los tiburones altamente migratorios a los fenómenos climáticos de gran escala, y su posible relación con el efecto del calentamiento global. Se utilizaron dos fuentes de datos diferentes, ambas de áreas geográficas diferentes: mar de Alborán y mar Balear. Los resultados indican que la abundancia local de tiburones pelágicos podría estar mediada por la oscilación ártica.Palabras clave: Oscilación ártica, Calentamiento Global, Oscilación del Atlántico Norte, tiburones. AbstractBlue shark, shortfin mako shark and the thresher sharks are the three taxa of pelagic sharks most caught as bycatch in the Spanish pelagic longline fishery from Mediterranean Sea. The main aim of the present study was to analyse the effect of atmospheric oscillations about landing patterns of blue shark, shortfin mako shark, and thresher sharks from Spanish Mediterranean Sea, using a metaanalytical approach. The ultimate goal was to understand the response of highly migratory sharks to large-scale climate phenomena, and its possible link with the effect of global warming. Two different data sources were used from different geographical areas: Alboran Sea and Balearic Sea. The results indicate that the local abundance of pelagic sharks could be mediated by the Arctic Oscillation.

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Bycatch and release of pelagic megafauna in industrial trawler fisheries off Northwest Africa

Cited by 100 publications

References 12 publications

Assessing accidental entanglement as a threat to the Mediterranean monk seal Monachus monachus

Assessing accidental entanglement as a threat to the Mediterranean monk seal Monachus monachus

Live-captures of common bottlenose dolphins Tursiops truncatus and unassessed bycatch in Cuban waters: evidence of sustainability found wanting

Assessing the influence of the atmospheric oscillations on pelagic and highly migratory sharks bycatches from Spanish Mediterranean Sea, a meta-analytic approach

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