MEPS 184:171-182 (1999)  -  doi:10.3354/meps184171

ABSTRACT: The distribution patterns and feeding habits of 4 deep-water decapod species were investigated from samples collected in experimental trawl surveys carried out along the continental slope of Crete (Eastern Mediterranean) in 1994 to 1995, at depths between 100 and 1000 m. Despite their distribution overlap, the differences in the distribution patterns of the species along the depth gradient were clear, with Plesionika ensis and Polycheles typhlops occurring at greater depths than Parapenaeus longirostris and Plesionika heterocarpus. Stomach content analysis revealed that all species were active predators of benthic invertebrates, while scavenging activity became more important at depths below 500 m. The species exhibited highly diverse diets, but dietary diversity was higher for those inhabiting shallower depths. Ontogenetic dietary shifts were pronounced, although dietary patterns were also significantly affected by season and depth. Interspecific dietary overlap was less than intraspecific overlap between size classes and between months. Feeding intensity was associated with the distribution patterns of the species and decreased with depth, thus it was significantly lower for the species at the deepest depths, P. typhlops and P. ensis. Dietary patterns of the species examined were quite similar and differences noted were more consistent with depth-related changes in available food resources than with changes in the position of the species in the food web. Since dietary overlap among the species when they co-occur was high, it is possible that competitive trophic interactions accounted for the low overlap in the bathymetrical distribution of the species examined. Such interactions may be of fundamental importance on the deep-sea bottoms in the Eastern Mediterranean since environmental parameters such as temperature and salinity are rather constant.

KEY WORDS: Deep-water decapods · Distribution · Diet · Prey selection · Ontogeny · Diet breadth · Resource partitioning