Population characteristics unravel occurrence of distinct stocks of yellowfin tuna (Thunnus albacares) population in the Indian seas

Abstract

Fishery and biological observations of yellowfin tuna caught from seas surrounding theIndian mainland and its island territories have indicated the presence of biologically distinctstocks in the region. Those caught around the submerged mounts of Chagos-LaccadiveRidge in the Lakshadweep Sea, off Kerala-Karnataka coast exhibit early maturity, small sizeat maturity, short lifespan and a close association with sea mounts. In contrast, those caughtoff other coasts of the mainland, including Andaman waters, exhibit late maturity and largersizes at maturity indicating a fishery dominated by larger-sized individuals. These findingssuggest that the yellowfin tuna associated with the Lakshadweep Sea mounts constitutesa distinct stock, highlighting the necessity for comprehensive genetic, morphometric andpopulation investigations to confirm their stock status.   Keywords:Chagos-Laccadive Ridge, Indian mainland,Lakshadweep Sea, Maturity, Stock, Sea mounts,Yellowfin tuna