Food spectrum and dietary preferences of the Indian anchovy Stolephorus indicus (van Hasselt, 1823) from Thiruvananthapuram coast, Kerala

Abstract

The food preferences of the Indian anchovy Stolephorus indicus (van Hasselt, 1823) along the Thiruvananthapuram coast of Kerala was studied for a period of one year from June 2013 to May 2014, dividing the entire period into three seasons as pre-monsoon, monsoon and post-monsoon. A total of 141 samples were collected and the gut contents were analysed. The principal food item was the crustaceans which included copepods, lucifers, mysids, Acetes and amphipods. The other preferred prey items were molluscs (bivalves and gastropods), small fishes, tintinnids and dinoflagellates. The gastrosomatic and stomach fullness indices revealed almost uniform feeding preferences with copepods being the preferred food item throughout the three seasons. Analysis of variance showed significant (p0.05) seasonal variation was observed in the gut contents of S. indicus. Analyses of the different prey indices [prey diversity index (H), niche width indices (B) and prey evenness indices (e)] of S. indicus for the three seasons indicated an almost uniform distribution of prey species throughout the study period which directly indicate the abundance of the prey items and indirectly indicate a stable potential fishery and ecosystem.