夏秋季西北太平洋柔鱼渔业生物学的初步研究

Biological characteristics of Ommastrephes bartramii in northwest Pacific Ocean

摘要:

根据2007年7－10月我国鱿钓船在西北太平洋传统鱿钓作业渔场（150°~165°E，39°~45°N）渔汛期间所采集的柔鱼样本，对夏秋季柔鱼渔业生物学特性进行初步研究。研究得知，渔获物胴长范围为200~436 mm，平均胴长为282 mm，优势胴长为230~320 mm，占总数的81.60%。各月渔获物中雄性个体的平均胴长小于雌性个体。胴长与体重关系的生长指数接近3。渔获物中的性比符合1∶1（P>0.05），但成熟个体中雄性个体所占比例明显比雌性高（P<0.05）。渔获物的性腺成熟度以Ⅰ、Ⅱ期为主，雌性个体性腺成熟晚于雄性个体。缠卵腺长和缠卵腺重随着性腺的成熟而逐步增大。渔获物中胴长组成呈双峰型，且未成熟、成熟个体同时存在，由此判断作业海域中柔鱼存在2个种群，即小型的冬春季产卵群体和大型的秋季产卵群体，且以小型的冬春季产卵群体为主。

Abstract:

Based on the samples from Chinese squid jigging vessels in the traditional fishing area (150°-165°E，39°-45°N) of northwest Pacific in 2007, the biological characteristics of squid Ommestrephes bartramii were studied. The results showed that the range of mantle length was from 200 to 436 mm and the average mantle length attained 282 mm, the dominant mantle length ranged from 230 to 320 mm which accounted for 81.6 percent of the total. The monthly mantle length of male squid was smaller than that of female, the growth index of relationship between mantle length and body weight was nearly three. The sex ratio of total number accorded with 1∶1（P>0.05）, but the proportion of mature males was obviously higher than that of females（P<0.05）. The sexual maturity stage dominated Ⅰ and Ⅱ, the average maturity stage of females was less than that of males. The length and weight of nidamental gland of squid increased with the growth of gland maturity. Since the composition of mantle length had two modes in samples and immature and mature individuals both exist, it is concluded that the individuals of the catch could be divided into two populations in the northwest Pacific Ocean, i.e. winterspring cohort with smaller size and autumnspawning cohort with bigger size, in which the winterspring cohort dominated in the catch.