Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.

Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this popu...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Laura Mannocci, Willy Dabin, Emmanuelle Augeraud-Véron, Jean-François Dupuy, Christophe Barbraud, Vincent Ridoux
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/57f0687e9cb3475fbbd74aac3e6ec21a
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:57f0687e9cb3475fbbd74aac3e6ec21a
record_format	dspace
spelling	oai:doaj.org-article:57f0687e9cb3475fbbd74aac3e6ec21a2021-11-18T07:26:23ZAssessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.1932-620310.1371/journal.pone.0032615https://doaj.org/article/57f0687e9cb3475fbbd74aac3e6ec21a2012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22393423/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this population using a demographic modeling approach. We relied on a sample of females stranded along the French Atlantic and western Channel coasts. Strandings represent an extensive source of demographic information to monitor our study population. Necropsy analysis provided an estimate of individual age and reproductive state. Then we estimated effective survivorship (including natural and human-induced mortality), age at first reproduction and pregnancy rates. Reproductive parameters were consistent with literature, but effective survivorship was unexpectedly low. Demographic parameters were then used as inputs in two models. A constant parameter matrix proposed an effective growth rate of -5.5±0.5%, corresponding to the current situation (including bycatch mortality). Subsequently, deterministic projections suggested that the population would be reduced to 20% of its current size in 30 years and would be extinct in 100 years. The demographic invariant model suggested a maximum growth rate of +4.5±0.09%, corresponding to the optimal demographic situation. Then, a risk analysis incorporating Potential Biological Removal (PBR), based on two plausible scenarii for stock structure suggested that bycatch level was unsustainable for the neritic population of the Bay of Biscay under a two-stock scenario. In depth assessment of stock structure and improved observer programs to provide scientifically robust bycatch estimates are needed. Effective conservation measures would be reducing bycatch to less than 50% of the current level in the neritic stock to reach PBR. Our approach provided indicators of the status and trajectory of the common dolphin population in the eastern North Atlantic and therefore proved to be a valuable tool for management, applicable to other dolphin populations.Laura MannocciWilly DabinEmmanuelle Augeraud-VéronJean-François DupuyChristophe BarbraudVincent RidouxPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 2, p e32615 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Laura Mannocci Willy Dabin Emmanuelle Augeraud-Véron Jean-François Dupuy Christophe Barbraud Vincent Ridoux Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.
description	Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this population using a demographic modeling approach. We relied on a sample of females stranded along the French Atlantic and western Channel coasts. Strandings represent an extensive source of demographic information to monitor our study population. Necropsy analysis provided an estimate of individual age and reproductive state. Then we estimated effective survivorship (including natural and human-induced mortality), age at first reproduction and pregnancy rates. Reproductive parameters were consistent with literature, but effective survivorship was unexpectedly low. Demographic parameters were then used as inputs in two models. A constant parameter matrix proposed an effective growth rate of -5.5±0.5%, corresponding to the current situation (including bycatch mortality). Subsequently, deterministic projections suggested that the population would be reduced to 20% of its current size in 30 years and would be extinct in 100 years. The demographic invariant model suggested a maximum growth rate of +4.5±0.09%, corresponding to the optimal demographic situation. Then, a risk analysis incorporating Potential Biological Removal (PBR), based on two plausible scenarii for stock structure suggested that bycatch level was unsustainable for the neritic population of the Bay of Biscay under a two-stock scenario. In depth assessment of stock structure and improved observer programs to provide scientifically robust bycatch estimates are needed. Effective conservation measures would be reducing bycatch to less than 50% of the current level in the neritic stock to reach PBR. Our approach provided indicators of the status and trajectory of the common dolphin population in the eastern North Atlantic and therefore proved to be a valuable tool for management, applicable to other dolphin populations.
format	article
author	Laura Mannocci Willy Dabin Emmanuelle Augeraud-Véron Jean-François Dupuy Christophe Barbraud Vincent Ridoux
author_facet	Laura Mannocci Willy Dabin Emmanuelle Augeraud-Véron Jean-François Dupuy Christophe Barbraud Vincent Ridoux
author_sort	Laura Mannocci
title	Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.
title_short	Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.
title_full	Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.
title_fullStr	Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.
title_full_unstemmed	Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.
title_sort	assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/57f0687e9cb3475fbbd74aac3e6ec21a
work_keys_str_mv	AT lauramannocci assessingtheimpactofbycatchondolphinpopulationsthecaseofthecommondolphinintheeasternnorthatlantic AT willydabin assessingtheimpactofbycatchondolphinpopulationsthecaseofthecommondolphinintheeasternnorthatlantic AT emmanuelleaugeraudveron assessingtheimpactofbycatchondolphinpopulationsthecaseofthecommondolphinintheeasternnorthatlantic AT jeanfrancoisdupuy assessingtheimpactofbycatchondolphinpopulationsthecaseofthecommondolphinintheeasternnorthatlantic AT christophebarbraud assessingtheimpactofbycatchondolphinpopulationsthecaseofthecommondolphinintheeasternnorthatlantic AT vincentridoux assessingtheimpactofbycatchondolphinpopulationsthecaseofthecommondolphinintheeasternnorthatlantic
_version_	1718423476164886528

Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.

Ejemplares similares