海州湾小黄鱼幼鱼和黄鲫幼鱼的食物竞争

Food competition between juvenile Pseudosciaena polyactis and juvenile Setipinna taty taty in the Haizhou bay

中文关键词: 小黄鱼  黄鲫  饵料重叠  食物竞争

英文关键词: Pseudosciaena polyactis  Setipinna taty  Dietary overlap  Food competition

中文摘要:

      根据2008年7~8月在黄海海州湾海域进行的定点底拖网调查，应用胃含物分析法，多元统计分析法、饵料重叠系数法等，对小黄鱼（Pseudosciaena polyactis）幼鱼和黄鲫（Setipinna taty）幼鱼的食物竞争关系进行研究。结果表明，小黄鱼幼鱼和黄鲫幼鱼的营养级相同，均为3.33级。但是它们的食物组成相似性（0.06-0.20）和饵料重叠系数（0.03-0.38）并不高，均小于0.6，而两种鱼类幼鱼种内的食物组成相似性和饵料重叠系数则较高。从饵料组成来看，甲壳类中的真刺唇角水蚤（Labidocera euchaeta）和长额刺糠虾（Acanthomysis longirostris）在两种鱼类幼鱼体长/叉长较小阶段存在一定程度上的重叠，之后随着个体的生长发育，摄食逐渐产生分化。从本研究的结果判断小黄鱼幼鱼和黄鲫幼鱼之间可能存在较弱的种间资源利用性食物竞争，而两种鱼类幼鱼各自则可能存在较大的种内资源利用性食物竞争。

英文摘要:

      Pseudosciaena polyactis and Setipinna taty are two kinds of important commercial fish species in the northern East China Sea and the Bohai Sea, and they play an important role in the marine ecosystems. In our study, the dietary overlap and food competition between these two juvenile fish species at their common length of 35~69 mm were examined by applying the multivariate statistical technique, the Schoener’s similarity index, and the Pianka index, based on the total of 547 samples collected from seasonal bottom trawl surveys in the Haizhou Bay of the Yellow Sea during July~August, 2008. The results indicated that these two juvenile fish species had the same trophic level of 3.33. Both the Schoener’s similarity index (0.06~0.20) and dietary overlap coefficient (0.03~0.38) between juveniles of the two fish species were lower than 0.6. In contrast, their intra-specific values of food composition similarity and dietary overlap coefficient were relatively high. At the species level, crustaceans including Labidocera euchaeta and Acanthomysis longirostris were the common preys in the developing prophase of the two fish species. Then different changes in diet appeared as the two juvenile fish grew. We conclude that there is low inter-specific competition between juveniles of these two fish species and high intra-specific competition within each species.