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Auteur Capietto, A.; Escalle, L.; Chavance, P.; Dubroca, L.; Delgado de Molina, A.; Murua, H.; Floch, L.; Damiano, A.; Rowat, D.; Mérigot, B.
Titre Mortality of marine megafauna induced by fisheries: Insights from the whale shark, the world’s largest fish Type Article scientifique
Année (down) 2014 Publication Revue Abrégée Biological Conservation
Volume 174 Numéro Pages 147-151
Mots-Clés Apparent survival; Bycatch; Hotspots of interaction; marine conservation; Megafauna; Rhincodon typus
Résumé The expansion of human activities is endangering megafauna in both terrestrial and marine ecosystems. While large marine vertebrates are often vulnerable and emblematic species, many are considered to be declining, primarily due to fisheries activities. In the open ocean, certain fisheries improve their efficiency of detecting tuna schools by locating and fishing close to some macro-organisms, such as whale sharks or marine mammals. However, collecting accurate data on the accidental capture and mortality of these organisms is a complex process. We analyzed a large database of logbooks from 65 industrial vessels with and without scientific observers on board (487,272 and 16,096 fishing sets since 1980 and 1995 respectively) in both the Atlantic and Indian Oceans. Distribution maps of Sightings Per Unit of Effort highlights major hotspots of interactions between the fishery and whale sharks in the coastal area from Gabon to Angola in the Atlantic from April to September, and in the Mozambique Channel in the Indian Ocean between April and May. The incidence of apparent whale shark mortality due to fishery interaction is extremely low (two of the 145 whale sharks encircled by the net died, i.e. 1.38%). However, these two hotspots presented a relatively high rate of incidental whale shark capture. Thus, we underline the importance of estimating long-term post-release mortality rates by tracking individuals and/or by photographic identification to define precise conservation management measures.
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ISSN 0006-3207 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 347
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Auteur Grüss, A.; Kaplan, D.M.; Robinson, J.
Titre Evaluation of the effectiveness of marine reserves for transient spawning aggregations in data-limited situations Type Article scientifique
Année (down) 2013 Publication Revue Abrégée ICES J. Mar. Sci.
Volume Numéro Pages
Mots-Clés coral reef fish; fisheries closures; marine conservation; Marine Protected Areas; protogynous hermaphrodites; resource management
Résumé Grüss, A., Kaplan, D. M., and Robinson, J. Evaluation of the effectiveness of marine reserves for transient spawning aggregations in data-limited situations. – ICES Journal of Marine Science, doi:10.1093/icesjms/fst028. Many coral reef fish species form predictable, transient spawning aggregations. Many aggregations are overfished, making them a target for spatial management. Here, we develop a per-recruit model to evaluate the performance of no-take marine reserves protecting transient spawning aggregations. The model consists of only 14 demographic and exploitation-related parameters. We applied the model to a protogynous grouper and a gonochoristic rabbitfish from Seychelles and tested six scenarios regarding the extent of protected areas, the level of fish spawning-site fidelity, and fishing effort redistribution post reserve implementation. Spawning aggregation reserves improve spawning-stock biomass-per-recruit and reduce the sex ratio bias in protogynous populations for all scenarios examined. However, these benefits are often small and vary among the different scenarios and as a function of sexual ontogeny. In all scenarios, increases in yield-per-recruit do not occur or are negligible. The long-term yield increases due to spawning aggregation reserves may still occur, but only if spawning-stock biomass recovery results in a recruitment subsidy. Given these limited benefits, the value of no-take reserves must be weighed against those of other management options, such as fishing effort reduction and seasonal fishery closures. The latter is particularly appropriate when spawning and non-spawning areas overlap in space.
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Editeur Lieu de Publication Éditeur
Langue en Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1054-3139, 1095-9289 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 259
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