舟山渔场细点圆趾蟹(Ovalipes punctatus)生物学特性及其季节变化

BIOLOGICAL CHARACTERISTICS AND SEASONAL VARIATIONS OF OVALIPES PUNCTATUS IN THE ZHOUSHAN FISHING GROUND

根据2006—2007年在舟山渔场渔业资源调查中采集的细点圆趾蟹样品,开展了生物学特性研究,对生物学特性的季节变化进行了分析,并将结果与以往报道进行了比较。结果表明,舟山渔场细点圆趾蟹甲长分布范围9—75mm,平均43.8mm,甲宽10—98mm,平均54.9mm。体重分布范围0.4—167.4g,平均40.4g。雄性个体大于雌性。雌、雄个体甲宽分布随季节变化明显,春季小个体以雌性为主,夏季雌、雄个体甲宽组成比例基本一致,秋、冬季雄性大个体明显增加。雌、雄性比约为1:1.03,与从前报道差异较大。摄食强度以1级为主,占41.3%,平均摄食等级为1.87。与以往研究结果比较,细点圆趾蟹呈现小型化趋势,并且生长速度加快。研究结果还表明,生物学特性季节变化分析能够反映伏季休渔及随后的持续捕捞对细点圆趾蟹个体生长和资源变动产生的影响。

Based on the samples of Ovalipes punctatus collected from fisheries resource survey in the Zhoushan fishing ground from 2006 to 2007, we reported the biological characteristics of O. punctatus, analyzed their seasonal variations, and compared our results with previous studies. The carapace length of O. punctatus varied from 9 to 75mm, with an average value of 43.8mm; the carapace width varied from 10 to 98mm, with an average value of 54.9mm. The body weight ranged from 0.4 to 167.4g, with an average value of 40.4g. The male individuals were larger than females. Significant seasonal variations of carapace width were observed in both female and male O. punctatus. Small individuals dominated the O. punctatus population in spring; in summer, the composition proportions of carapace width were similar for female and male; and larger male individuals significantly increased in winter. The female and male ratio was about 1：1.03, which was greatly different with previous reports. The feeding intensities were mainly at level 1, occupying about 41.3%; and the average feeding intensity level was 1.87. Compared with previous research results, the O. punctatus became smaller, but grew faster. The results also indicated that the non-finishing practice in summer and the subsequent continuous fishing could affect individual growth and resource dynamics.