Feeding traits and diet diversity of Heterocarpus chani Li, 2006 (Decapoda: Caridea: Pandalidae) from southeastern Arabian Sea

Abstract

A comprehensive exploration into the diet diversity and feeding strategy of the deep-sea shrimp, Heterocarpus chani, involved the analysis of 274 specimens gathered from the southeastern Arabian Sea, revealing discernible differences in food preference based on factors such as sex, size, and season. Detritus emerged as the predominant dietary element, followed by crustaceans, foraminiferans, and fish remains. The index of preponderance revealed detritus accounting for 83.3 % in males, 71.5 % in berried females, and 67.9 % in non-berried females. It was noted that males exhibited a higher level of feeding intensity compared to females. The percentage of active feeders is higher in both males (48.2 %) and berried females (38.6 %) in comparison with moderately fed and poorly fed groups. During the post-monsoon season, both male and female H. chani showed peak feeding activity and intensity. Remarkably, within the female population, the highest feeding activity was noted among juvenile individuals, potentially contributing to accelerated somatic and ovarian development. Upon assessing the gastro somatic index, it became apparent that male H. chani exhibited greater efficiency as predators compared to their female counterparts. Throughout the entire study period, the average vacuity index remained consistent, standing at 22.8 % for males, 22.8 % for berried females, and 23.4 % for non-berried females. Instances of empty stomachs were observed across all seasons, with the highest proportion noted during the pre-monsoon period in both sexes.