A first estimate of sea turtle bycatch in the industrial trawling fishery of Gabon

Gabon hosts nesting grounds for several sea turtle species, including the world’s largest rookery for the leatherback turtle ( Dermochelys coriacea ), Africa’s largest rookery for the olive ridley turtle ( Lepidochelys olivacea ) and smaller aggregations of the hawksbill turtle ( Eretmochelys imbric...

Full description

Saved in:

Bibliographic Details
Published in:	Biodiversity and conservation Vol. 26; no. 10; pp. 2421 - 2433
Main Authors:	Casale, Paolo, Abitsi, Gaspard, Aboro, Marie Pierre, Agamboue, Pierre Didier, Agbode, Laureen, Allela, Nontsé Lois, Angueko, Davy, Bibang Bi Nguema, Jean Noel, Boussamba, François, Cardiec, Floriane, Chartrain, Emmanuel, Ciofi, Claudio, Emane, Yves Armand, Fay, J. Michael, Godley, Brendan J., Kouerey Oliwiwina, Carmen Karen, de Dieu Lewembe, Jean, Leyoko, Donatien, Mba Asseko, Georges, Mengue M’adzaba, Pulcherie, Mve Beh, Jean Hervé, Natali, Chiara, Nyama-Mouketou, Clauvice, Nzegoue, Jacob, Ogandagas, Carole, Parnell, Richard J., Rerambyath, Guy Anicet, Gnandji, Micheline Schummer, Sounguet, Guy-Philippe, Tiwari, Manjula, Verhage, Bas, Vilela, Raul, White, Lee, Witt, Matthew J., Formia, Angela
Format:	Journal Article
Language:	English
Published:	Dordrecht Springer Netherlands 01-09-2017 Springer Springer Nature B.V
Subjects:	Aquatic reptiles Biodiversity Biomedical and Life Sciences Breeding Bycatch Climate Change/Climate Change Impacts Coastal and marine biodiversity Coma Conservation Biology/Ecology Ecological aggregations Ecology Estimates Fisheries Fishing Fishing effort Green turtle Hosts Industrial fisheries Life Sciences Man-induced effects Mortality Mortality causes Nesting Observers Onboard Original Paper Reptiles & amphibians Rookeries Sea turtles Species Trawlers Trawling Turtles Gabon Gabon Trawling fishery Olive ridley Catch rate Mortality
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Gabon hosts nesting grounds for several sea turtle species, including the world’s largest rookery for the leatherback turtle ( Dermochelys coriacea ), Africa’s largest rookery for the olive ridley turtle ( Lepidochelys olivacea ) and smaller aggregations of the hawksbill turtle ( Eretmochelys imbricata ) and green turtle ( Chelonia mydas ). To assess the level of incidental captures of turtles by the Gabonese trawl fishery, an onboard observer program was conducted in the period 2012–2013. A total of 143 turtles were captured by 15 trawlers during 271 fishing days. The olive ridley turtle was the main species captured (80% of bycaught turtles), with mostly adult-sized individuals. The remaining 20% included green turtles, hawksbill turtles, leatherback turtles and undetermined species. Bycatch per unit of effort (BPUE) of olive ridley turtles varied greatly depending on the period of the year (range of means: 0.261–2.270). Dead and comatose turtles were 6.2 and 24.6% respectively (n = 65). By applying the available fishing effort to two BPUE scenarios (excluding or considering a seasonal peak), the total annual number of captures was estimated as ranging between 1026 (CI 95% 746–1343) and 2581 (CI 95% 1641–3788) olive ridley turtles, with a mortality ranging from 63 (CI 95% 13–135) to 794 (CI 95% 415–1282) turtles per year depending on the scenario and on the fate of comatose turtles. Such a potential mortality may be reason for concern for the local breeding population of olive ridley turtles and recommendations in terms of possible conservation measures and further research are given.
ISSN:	0960-3115 1572-9710
DOI:	10.1007/s10531-017-1367-z