Food and feeding habits of the kingseer, Scomberomorus commerson (Lacepede), in the seas around the Indian Peninsula

Abstract

The kingseer prey on surface schooling species like the sardines and the whitebaits. Year-to-year changes in the abundance and recruitment of lesser sardine stocks reflect well in the abundance and size of the prey in the gut. The fish change over from whitebaits to sardines at a size which is about 1113th its asymptotic length (2081 mm). A linear relation exists between the size of fish caught and the size of bait used for a given hook size of troll. The high incidence of anteroposterior orientation of prey (67.8%) in the gut, small number of gill rakers, strong dentition, larger prey size, and a more fusiform and robust body indicate the kingseer to be a very aggressive predator. Inhaspecific competition is apparent from a drastic reduction in the ration level at the peak of kinpeer abundance. Ration per unit body weight is much higher in the younger fish. Maturing and ripe fish increase their food intake considerably. Conversion factor and gross growth efficiency indicate considerable energy loss on account of the fast swimming and aggressive habits. The slope of the T-line, q=0.9106, shows that the fish live on optimum levels of diet in a normal nonstress state. The maximum level of growth eficiency at low feeding levels K- e4- 0.23, is outside the range of values, 0.25 to 0.75, obtained in feeding experiments. The von Bertalanffy model describes the weight growth of kingseer much better than the growth models built on food utilisation parameters.