Abstract

The spawning period, length and age at maturity of jack mackerel (Trachurus murphyi) in the Chilean coast is analyzed. The histological gonadal inspection confirmed that reproductive period of this species ranges between September and January. During the spawning season of 2011 the length at maturity (L-50) of females was estimated in 22.7 cm fork length (FL) equivalent to an age of 2.44 years (E-50). For males, the limited presence of immature individuals, did not allow to estimate the L-50 and E-50. However, the observed data suggest that the maturation process is different between sexes. Males reached full maturity between 21 and 23 cm FL, around 2-3 years, while females did so between 24 and 25 cm FL, at 4 years. The length at maturity in females did not show significant differences from previous estimates conducted through histological analysis. The lack of reproductive information in the beginning of the fisheries along with the differences in estimation methods, make difficult to reach reliable conclusions on a possible reduction in maturity length in females in recent years.