哥斯达黎加外海茎柔鱼繁殖特性研究

In this paper, we analyzed the reproduction of the Humboldt squid (Dosidicus gigas) base on 281 individuals collected off the Costa Rican waters between July and August in 2009 by Chinese jigging vessels. The number of females of D. gigas was significant more than that of males in the study area and the ratio of female to male was 3.76:1. There was significant higher percentage mature female (66.7%) and male (96.7%) in the study area. The area off Costa Rica was considered to be a potential spawning ground due to a higher percentage of mature females there, and D. gigas began spawning after August. Nidamental gland length showed significant power correlations with nidamental gland weight. Nidamental gland and gonad somatice index increased with gonad maturity gradually from gonad maturity stage I to Ⅳ, but slightly decreased at stage Ⅴ due to mating and spawning (U-test p < 0.05). The distribution pattern of nidamental gland and gonad somatice index of mature individuals concluded that there existed one small group off the Costa Rica waters. The relative frequency distribution for Mantle Length classes fitted to logistic model showed that sizes at maturity of D. gigas was 291 mm for females, and at least less than 250 mm for males.