Field estimation of daily ration in deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) in the western Mediterranean

Abstract

Estimates of the daily ration consumed by the deep-sea shrimp Aristeus antennatus were obtained from 18 h of continuous trawl sampling conducted over the mid-slope (between 610 and 710 m depth) of the Catalan Sea (NW Mediterranean). This deep-sea environment is characterized by constant and relatively warm temperature (13 ± 0.5°C) throughout the year. Two independent daily-ration estimates were produced: First, an actual daily ration was obtained by computing the weight of the fresh food items, yielding a value of 2.588 g wet food weight per 100 g shrimp wet weight. Second, the daily ration was estimated by the models of Eggers and Elliot and Persson. Daily rations for A. antennatus computed from these models ranged between 1.666 (±1.193) and 2,315 (±0.924) g wet food weight per 100 g shrimp wet weight, or between 0.130 (±0.115) and 0.223 (±0.091) g dry food weight per 100 g shrimp wet weight. The results of the 3 daily-ration models were compared and tested by bootstrapping; they did not differ significantly. Our results are compared with daily rations reported for other marine organisms. The feeding ecology of A. antennatus is discussed in relation to the food-limited deep-sea environment which this shrimp inhabits.