Feeding ecology of deep-water Arabian red shrimp, Aristeus alcocki Ramadan, 1938 (Decapoda: Penaeoidea: Aristeidae) from southwestern India (Arabian Sea)

Abstract

The Arabian red shrimp, Aristeus alcocki Ramadan, 1938 constitutes a commercially important decapod in the southern coast of India with an annual average catch of greater than 2,122 tons. The diet contents in connection to the sex, maturity, season and size group of this species were investigated using an aggregate number of 634 samples collected from the south-west coast of India. The diet components of A. alcocki were deduced to consist of 71 prey categories, which belonged to smaller crustaceans (e.g. amphipods, decapods, euphausiids), foraminiferans (Rotaliida, and Miliolida), molluscs (bivalves, gastropods, and cephalopods), polychaetes, and bryozoans. Feeding pattern of the studied species was examined using Amundsen graphical method, which recognized that A. alcocki exhibited different degrees of generalization and specialization with various preys. The marginal seasonal variation related to major prey items could be attributed to the environmental fluctuations of the deep waters and other biological processes. Considering stomach fullness and food quality, the females of A. alcocki were found to be the effective predators than males. The parameters, such as population characteristics, somatic and gonadal development might be attributed to this variation. Notably, the larger-sized animal have good swimming ability, which could help in an effective selection of prey, while the smaller individuals depend on the epibenthic organisms for their food. This study comprises the first report on the feeding biology of A. alcocki in the Arabian Sea.