小黄鱼Larimichthys polyactis体长-体重关系幂指数与产卵群体空间分布相关性研究

鱼类产卵群体的相关研究一直是渔业领域关注的热点,对鱼类的产卵期、产卵场的研究是鱼类生态习性研究方向的重要组成部分。本文在前期研究证实鱼类体长-体重关系幂指数可以指示鱼类产卵期的基础上,利用2004年4个季节的东海大面积调查数据,尝试利用同一时间点上的各个调查点幂指数信息来分析鱼类产卵场分布特征,结果发现,成熟产卵个体仅在春季出现,而未成熟产卵个体4季均有分布,以此推测小黄鱼存在"跳过产卵"现象。另外发现,单靠幂指数大小,不能区分各个产卵成熟阶段,也不能区分产卵个体与非产卵个体;而怀卵个体出现站点的幂指数平均值偏低于匀速生长,空间上也具有类似特征,即幂指数相对低的地方一般对应怀卵个体相对集中的水域。本文依据幂指数分布,推断小黄鱼成熟产卵群体有3块相对集中水域,即舟山渔场近海、济州岛西南侧和江外与舟外渔场临近水域。

Study on the correlation between spatial distributions of the spawning groups and the power b in length-weight relation function of small yellow croaker(Larimichthys polyactis)

Studies on fish spawning group are always the focus of fisheries science. Spawning periods and areas are important parts of fish ecological habit studying. Power b in exponent relationship between fish body length and weight as spawning period indicator has been tested and proved with one whole year data in previous paper. Based on the above,this study tries to analysis the spatial character of fish spawning groups by power b at a time point with the data collected from a bottom trawl survey in the 4 seasons of 2004 in the East China Sea. The results show that,ripening small yellow croakers appeared only in spring,however immature individuals appeared in all of 4 seasons,which suggests the presence of "skip spawning" phenomenon. Another finding is that different spawning mature stages can not be distinguished only based on the value of power b,neither the difference between the spawning and non-spawning; while the average power b of sites including spawning individuals appeared lower than that in a constant speed growing,and similar characteristics also occurred in the space,where the relatively low power b generally occurred in the waters with relative high concentration of spawning individuals. Based on power b,three areas with relative high concentration of ripening individuals were inferred,including the offshore of Zhoushan fishing ground,the southwest side of Jeju Island and the adjacent water between Jiangwai and Zhouwai fishing grounds.