Feeding strategies and diet composition of yellowfin tuna Thunnus albacares (Bonnaterre, 1788) caught along Andhra Pradesh, east coast of India

Abstract

The food of yellowfin tuna, Thunnus albacares caught by longlines off the east coast of India was studied in detail. Contents of 146 non-empty stomachs were analysed for the Index of relative importance (IRI) and prey specific abundance. T. albacares caught by the longline were found to be non-selective generalist feeders, foraging on micronektonic, pelagic or benthic organisms available in the epipelagic waters. Teleost fish, crabs, squids and shrimps were the major component of food items. Priacanthus hamrur was the most preyed upon fish with a high IRI (40.5%) followed by the swimming crab Charybdis smithii (23.9%), the squid Sthenoteuthis oualaniensis (15.5%) and prawn Solenocera hextii (10.3%). Being a large pelagic predator, it formed an important link in the food chain of the ocean system and also formed a good collector of the less exploited micronekton organisms of the deep scattering layer (DSL).