Fishery and some aspects of reproductive biology of two coastal species of tuna, Auxis thazard (Lacepede, 1800) and Euthynnus affinis (Cantor, 1849) off north Andhra Pradesh, India

Extensive efforts are under way in many research laboratories around the world to study commercially important epipelagic, highly migratory species of tunas. Acquisition of fishery data and information on reproduction of tunas is of utmost importance for proper management of tuna fishery. Reproduction in tunas is one of the least studied aspect and there is no information available on this aspect from the north Andhra Pradesh coast. The present paper incorporates information on fishery and results of the study undertaken to understand some aspects pertaining to reproduction, particularly spawning potential (fecundity), spawning period, maturity of gonads in relation to size of the fish, ova diameter ineasurements and gonado-somatic indices of two coastal tuna species, Auxis thazard (frigate tuna) and Euthynnus affinis (kawakawa) that are represented in the commercial catches of this region. The present data has been critically compared and discussed with the data from other regions.