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MEPS 241:41-55 (2002)
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Abstract
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Trophic relationships in a Mediterranean deep-sea fish community: partition of food resources, dietary overlap and connections within the benthic boundary layer
Maite Carrassón1,*, Joan E. Cartes2
1Departamenteo Biología Animal, Biología Vegetal y Ecología, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
2Centre Mediterrani d'Investigacions Marines I Ambientals, CSIC, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
*E-mail: maite.carrasson@uab.es
ABSTRACT: Food resource partitioning and some trends in the feeding ecology of 13 species of fishes inhabiting the slope of the Catalan Sea (western Mediterranean) were examined. Specimens were collected from 1987 to 1991, using bottom trawls at depths
between 1000 and 2250 m. Prey selection was also examined in relation to data collected in the same area on 2 potential prey compartments for fish, the benthopelagic macrofauna--suprabenthos or hyperbenthos--and the megafaunal decapod crustaceans. Thus, the
possible connections with prey availability within the benthic boundary layer (BBL) were also analysed. The size of available food resources was the most important factor responsible for food resource partitioning, both by depth stratum and season. The
importance of the variable predator size is also evidenced. Most of the deep-sea demersal fish species inhabiting the Catalano-Balearic slope often consumed a variety of available resources in their diets, mainly comprising suprabenthos, but also infauna
or planktonic prey. Thus, the BBL macrofauna constitute an important part of the available food exploited, with the range of the prey consumed increasing for the largest predators. A significant trend to increase dietary H' values within the depth
interval where each species attained its maximum abundance was observed. Some (positive) prey selection upon certain prey groups was detected depending on the fish species: sharks, Alepocephalus rostratus and Nettastoma melanurum
preferentially preyed on decapods, siphonophores and pyrosomids; Polyacanthonotus rissoanus, macrourids, Lepidion lepidion and Cataetyx alleni preyed upon suprabenthic peracarid crustaceans; and only Bathypterois
mediterraneus preferentially consumed copepods, the numerically dominant group in the bathyal BBL. Resource partitioning was high among the fish assemblage analysed in relation to the generally low dietary overlap values recorded. Overall, dietary
overlap values among fish species decreased with increasing depth.
KEY WORDS: Resource partitioning · Dietary overlap · Interaction prey-predator · Deep sea ecology · Western Mediterranean
Full text in pdf format
Published in MEPS Vol.
241
(2002) on October 4
Print ISSN: 0171-8630; Online ISSN: 1616-1599.
Copyright © Inter-Research, Oldendorf/Luhe, 2002
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