MORPHOLOGICAL-DIETARY RELATIONSHIPS WITHIN 2 ASSEMBLAGES OF MARINE DEMERSAL FISHES

In this study we have used morphological characters related to feeding and prey capture and dietary data to investigate the trophic organiza tion within two assemblages of marine demersal fishes. Morphological a nd dietary disparities within fish assemblages were estimated from spe cies similarities based on Euclidean distances plus species projection s on the principal axes from multivariate analyses. The analyses of th e morphological variables indicated that species in each assemblage co mprised morphologically distinct groups strongly influenced by trophic ally linked characters. Stomach content analyses revealed that fish sp ecies in each assemblage were classified into three basic feeding grou ps: polychaete-shrimp feeders, crab feeders and fish feeders. These re sults indicated that food resource partitioning was operating within e ach assemblage. However, when morphological and trophic data were comp ared no significant correlations were found. The results did not parti cularly support the ecomorphological hypothesis that dietary differenc es are due to morphological differences, since similar diets do not co rrespond to similar morphologies. The patterns of trophic organization within the fish assemblages examined, possibly reflect differences am ong species due not only to the effect of ecological demands on morpho logy but also by their evolutionary history and constructional constra ints imposed by phylogeny.