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Feeding ecology of conger eels (Conger conger) in north-east Atlantic waters

Published online by Cambridge University Press:  03 August 2009

José C. Xavier ,
Yves Cherel ,
Carlos A. Assis ,
João Sendão  and
Teresa C. Borges
José C. Xavier*
Affiliation:
Centre of Marine Sciences (CCMAR), University of Algarve, Faculty of Marine and Environmental Sciences (FCMA), Campus de Gambelas, 8000-139 Faro, Portugal Centre d'Etudes Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, BP 14, 79360 Villiers-en-Bois, France
Yves Cherel
Affiliation:
Centre d'Etudes Biologiques de Chizé, UPR 1934 du Centre National de la Recherche Scientifique, BP 14, 79360 Villiers-en-Bois, France
Carlos A. Assis
Affiliation:
University of Lisbon, Faculty of Sciences, Department of Animal Biology and Institute of Oceanography, Campo Grande, 1749-016 Lisbon, Portugal
João Sendão
Affiliation:
Centre of Marine Sciences (CCMAR), University of Algarve, Faculty of Marine and Environmental Sciences (FCMA), Campus de Gambelas, 8000-139 Faro, Portugal
Teresa C. Borges
Affiliation:
Centre of Marine Sciences (CCMAR), University of Algarve, Faculty of Marine and Environmental Sciences (FCMA), Campus de Gambelas, 8000-139 Faro, Portugal
*
Correspondence should be addressed to: J.C. Xavier, Institute of Marine Research, University of Coimbra, 3004-517 Coimbra, Portugal email: JCCX@cantab.net
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Abstract

In order to understand how marine ecosystems function, it is essential to study the trophic interactions among the community members, particularly from poorly known regions. In this study, the feeding ecology and diet of conger eels, Conger conger, an abundant fish species with commercial interest, was examined in the north-east Atlantic, off Algarve (southern Portugal) between May 2005 and August 2006. The diet was characterized by species composition, size and mass of prey. Conger eels are opportunistic feeders, cannibalistic, feeding on benthopelagic/pelagic prey (67% by mass and 71% by number) but also benthic prey (32% by mass and 29% by number). Fish (67.8±4.7% in mass) are the main prey of conger eels, followed by cephalopods (16.5±3.8%) and crustaceans (15.6±3.7%). The most numerous (identifiable) fish consumed were Capros aper, occurring in 90% of the stomach samples that contained food and representing 1.4% in mass, and Scomber japonicus, the most important fish in mass (21.1%), which occurred in 4.2% of the stomach samples that contained food. The present study shows that octopodids can play a more important role in the diet of conger eels than previously thought. Of the species preyed upon by conger eels, six species (21% of the total prey taxa) are caught commercially (Trachurus trachurus, Scomber japonicus, Micromesistius poutassou, Helicolenus dactylopterus and Conger conger) by local fisheries. As discards by local trawl and longline fisheries do not correspond with the diet of C. conger, it is likely that most prey of C. conger in rocky areas were caught actively in that study region.

Keywords

trophic interactionsdietconger eelsnorth-east Atlanticfisheries
Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 90 , Issue 3 , May 2010 , pp. 493 - 501
Copyright
Copyright © Marine Biological Association of the United Kingdom 2009

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