Feeding ecology of the deep-water aristeid crustacean Aristeus antennatus

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Abstract
Feeding habits and intraspecific dietary overlap in the shrimp Aristeus-antennatus (Risso, 1816) were studied. A comparative analysis of the diet of the 3 main size classes was also made taking into account sex and season as possible factors influencing diet. Dietary diversity was evaluated and overlap and resource partitioning considered. A. antennatus preys upon the bottom-dwelling community. Stomach content analysis indicated that the diet (percent abundance) consists chiefy (near 50%) of bivalves, the burrowing macruran Calocaris macandreae, polychaetes, amphipods, and ophiuroids. Differences were found in the diet composition of the various size classes, which exploit different resource levels, though ovelap was high (Schoener index: maximum = 0.8405, minimum = 0.7179). Larger individuals root deeper into the substratum when feeding: the activity of smaller males and females is confined to the surface layer. Size class and depth of foraging in the substratum were more highly related than size class and prey size. Diet composition varied significantly between seasons, with the proportion of prey items that live buried in the substratum gradually decreasing between spring and winter (overflap index = 0.5576). Dietary diversity values were consistently high in all cases and variation was slight. However, variation was higher between seasons than between sexes or size classes.