Skip Navigation

ICES Journal of Marine Science: Journal du Conseil 2000 57(3):525-530; doi:10.1006/jmsc.2000.0717
© 2000 by ICES/CIEM International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer
This Article
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Ménard, F.
Right arrow Articles by Marchal, E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Ménard, F.
Right arrow Articles by Marchal, E.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Exploitation of small tunas by a purse-seine fishery with fish aggregating devices and their feeding ecology in an eastern tropical Atlantic ecosystem

F. Ménard, A. Fonteneau, D. Gaertner, V. Nordstrom, B. Stéquert and E. Marchal

IRD HEA BP 5045, 34032 Montpellier Cedex 1, France
IRD, Centre de Recherches Océanologiques BP V 18, Abidjan, Côte d'Ivoire
IRD, Institut Océanographique 195 Rue St-Jacques, 75005 Paris, France

(tel: +33 4 67 63 69 82; fax: +33 4 67 63 87 78; e-mail: menard{at}mpl.ird.fr)

We investigated the effects of a purse-seine fishery with drifting fish aggregating devices (FADs) in the South Sherbo area of the Equatorial Atlantic, located between 0–5°N and 10–20°W. There had been no surface fishing activity in the area until 1975. Since 1991, fishing operations on schools of tuna associated with FADs has become widespread and this offshore area has developed into a major fishing zone. Exploitation rates are high between November and January. The fishery exploits multispecies concentrations of skipjack (71%), bigeye (15%), and yellowfin (14%) tunas of similar size (mode: 46-cm forklength). The use of FADs increased the vulnerability of small tunas and induced changes in fishing patterns. The mean individual weight of skipjack caught has decreased since 1991, due either to overfishing or to a growth change. Data from scientific observers were used to estimate discards and by-catches generated by FAD fishing during 1998. Discards of tunas (including frigate and little tunas) represented 7.6% of the total catch. Other by-catch (dominated by wahoo, billfish, triggerfish, sharks, barracudas, and dolphinfish) represented 2.3%, including 0.4% discarded at sea. Stomach content analysis showed that a mesopelagic species, Vinciguerria nimbaria (Photichthyidae), which during daylight concentrated in the upper layers in dense schools, was the main prey of all small tunas. The South Sherbro area appears to have exceptional environmental conditions. It is suggested that the FAD fishery may have wide-ranging effects on the migration of tunas in general and on the productivity of the skipjack population in particular.

Keywords: by-catch, discards, fish aggregating devices (FADs), feeding, mesopelagic fish, purse-seine fishery, tunas


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.