abstract:The catch of moon fish, Mene maculata, from the southwestern waters off Taiwan declined significantly in recent years. In order to examine the effect of exploitation on growth and age structure of moon fish, two length frequency data sets during the two periods 1981-1984 and 1995-1997 were analyzed with multiple length frequency analysis (MULTIFAN). The parameters of von Bertalanffy growth equation (VBGE) estimated by MULTIFAN were as followings: 1981-1984: asymptotic standard length L∞=279.8 mm, growth rate K=0.186/yr, t0=-1.7 yr, three age classes were identified and mean length was 110.5 mm, 139.2 mm, and 163.1 mm for ages 1-3, respectively. For 1995-1997 period, L∞=218.5 mm, K=0.285/yr, t0=-1.34 yr, four age classes were identified and mean length was 106.3 mm, 134.2 mm, 155.1 mm and 170.8 mm for ages 1-4, respectively. Significant difference on the VBGE between the two periods was found with Hotelling's test. Smaller asymptotic length and faster growth rate of the 1995-1997 period suggested that the moon fish compensate the effect of increasing of fishing effort through a density-dependent growth.