Habitat and Biology

An epipelagic, neritic as well as oceanic species.

In the eastern Pacific, mature fish occur throughout the year, though off Costa Rica spawning is heaviest from December through April, while in Japanese waters it peaks in July as expressed by the index of sexual maturity (Yasul, 1975). In the southern Indian Ocean, the spawning season extends from August to April; north of the equator it is reported from January to April. Fecundity was estimated at about 1.37 million eggs per year in a 44.2 em long female. Fecundity of fish in Indian waters ranged between approximately 200 000 to 1.06 million eggs per spawning in correlation with size of females.

Interest to Fisheries

Catches of Auxis are usually not identified to species because of current problems in identification. It may, however, be assumed that the Pacific and Indian Ocean catches reported by Japan, the Philippines and the Maldives are predominantly A. thazard . In the period from 1977 to 1980 these catches almost doubled to 122 995 metric tons, particularly due to increased landings by the Philippines, but decreased to about 98 000 metric tons 1981 (FAO, 1983). The total catch in 1996 (Auxis rochei and A. thazard ) was 172 693 t. Mainly Philippines 88 969 t. No catch in 1999