MEPS 522:255-268 (2015)  -  DOI: https://doi.org/10.3354/meps11149

Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans: interactions but few mortalities

Lauriane Escalle1,2,*, Anna Capietto1,2, Pierre Chavance2, Laurent Dubroca2, Alicia Delgado De Molina3, Hilario Murua4, Daniel Gaertner2, Evgeny Romanov5, Jérôme Spitz6, Jeremy J. Kiszka7, Laurent Floch2, Alain Damiano2, Bastien Merigot1

1Université de Montpellier, UMR 9190 MARBEC (UM, IRD, IFREMER, CNRS), Av. Jean Monnet, BP 171, 34203 Sète, France
2Institut de Recherche pour le Développement, UMR 9190 MARBEC (UM, IRD, IFREMER, CNRS), Av. Jean Monnet, BP 171,
34203 Sète, France
3Instituto Español de Oceanografía, Apdo. Correos 1373, 38080 S/C Tenerife, Canary Island, Spain
4AZTI Tecnalia, Herrera Kaia, Portualde z/g, 20110 Pasaia (Gipuzkoa), Spain
5CAP RUN - ARDA, Magasin No 10, Port Ouest, 97420 Le Port, Île de la Réunion, France
6Observatoire Pelagis, UMS 3462, CNRS / Université de La Rochelle, 5 allées de l’Océan, 17000 La Rochelle, France
7Florida International University, Department of Biological Sciences, North Miami, Florida 33181, USA
*Corresponding author:

ABSTRACT: Fisheries bycatch is considered to be one of the most significant causes of mortality for many marine species, including vulnerable megafauna. In the open ocean, tuna purse seiners are known to use several cetacean species to detect tuna schools. This exposes the cetaceans to encirclement which can lead to incidental injury or death. While interactions between fishers and cetaceans have been well documented in the eastern tropical Pacific Ocean, little is known about these interactions and potential mortalities in the tropical Atlantic and Indian Oceans. Here, we provide the first quantification of these interactions in both oceans by analyzing a large database of captain’s logbooks (1980 to 2011) and observations collected by onboard scientific observers (1995 to 2011). Distribution maps of sightings per unit effort highlighted main areas of relatively high co-occurrence: east of the Seychelles (December to March), the Mozambique Channel (April to May) and the offshore waters of Gabon (April to September). The percentage of cetacean-associated fishing sets was around 3% in both oceans and datasets whereas 0.6% of sets had cetaceans encircled. Of the 194 cetaceans encircled in a purse seine net (122 baleen whales, 72 delphinids), immediate apparent survival rates were high (Atlantic: 92%, Indian: 100%). Among recorded mortalities, 8 involved pantropical spotted dolphins Stenella attenuata and 3 involved humpback whales Megaptera novaeangliae. These high survival rates suggest that setting nets close to cetaceans has a low immediate apparent impact on the species involved. Our findings will contribute to the development of an ecosystem approach to managing fisheries and accurate cetacean conservation measures.


KEY WORDS: Apparent survival · Bycatch · Marine mammals · Fishery impact · Marine conservation · Megafauna


Full text in pdf format 
Cite this article as: Escalle L, Capietto A, Chavance P, Dubroca L and others (2015) Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans: interactions but few mortalities. Mar Ecol Prog Ser 522:255-268. https://doi.org/10.3354/meps11149

Export citation
Mail this link - Contents Mailing Lists - RSS
- -