Composición por tallas del atún aleta amarilla capturado por la flota atunera Mexicana en 1989

. In order to determine characteristics of the length composition of yellowfin tuna (Thunnus albacares) caught during 1989 by the Mexican tuna fleet in the eastern Pacific Ocean, we reviewed 41 samples (3977 individuals) obtained from landings made at four different Mexican ports. We designated six geographical zones in the catch area and analyzed the length frequency distributions of the fish by zone. The results show a predominance of fish less than 98 cm in the coastal zones, and larger than this size in oceanic zones. We also found that, within the coastal zones, yellowfin tend to be smaller in the north and larger in the south. The presence of small yellowfin tuna (58-98 cm) in oceanic zones is important because it confirms an earlier observation made by Suzuki et al. (1978; Inter.Amer.Trop.Tuna Comm. Bull., 17(5))