基于耳石地标点法的南黄海和东海小黄鱼种群关系研究

Otolith landmark-based relationship analysis of two Larimichthys polyactis subpopulations in Southern Yellow Sea and East China Sea

  • 摘要: 为比较不同地理群体的小黄鱼 (Larimichthys polyactis) 矢耳石形态特征,进一步明晰其种群划分问题,首次应用长于提取形态特征的地标点法探究了南黄海和东海小黄鱼群体的耳石形态学差异。2022年3—12月,于海州湾、吕泗、长江口和舟山渔场各采集30尾1龄小黄鱼,统一摘取其左矢耳石样本,在耳石外轮廓和耳石内听沟上分别提取了7和4个地标点,进行地标点法分析。结果显示:1) 耳石听沟上的地标点8—11相对扭曲贡献率总计为91.88%,耳石外轮廓上的地标点1—7的总贡献率为8.12%,表明4个地理群体小黄鱼的耳石形态差异主要来源于耳石听沟;2) 主成分分析散点图显示,部分海州湾群体明显可划分为1个类群,剩余海州湾群体和其他3个渔场所有群体高度重叠聚集为另一个类群,表明南黄海海域可能存在两个小黄鱼种群,即南黄海-东海群和北黄海-渤海群,同时也表明海州湾渔场存在着小黄鱼混栖群体。该现象可能是由于小黄鱼早期鱼卵、仔幼鱼阶段被动扩散和后期主动洄游造成的生境差异,从而诱导其耳石形态表型性状不同。研究结果证实了耳石地标点法在鱼类种间识别的可行性,从耳石形态学角度为中国近海小黄鱼的种群划分提供参考。

     

    Abstract: To compare the otolith morphology of different Larimichthys polyactis populations, and to further clarify their population division, we applied the landmark method better at extracting morphological features for the first time, to explore the morphological differences of otoliths from L. polyactis populations in the Southern Yellow Sea and East China Sea. From March to December 2022, 30 individuals of 1-year old fish had been collected from each from Haizhou Bay (HZB), Lyusi (LS), Yangtze Estuary (YTE) and Zhoushan (ZS) fishing grounds. After extracting the left sagittal otoliths, we seclected even landmarks in otolith contour and four landmarks in sulcus acusticus for the landmark analysis. Results show that: 1) Among the 11 landmarks, those in sulcus acusticus (Landmark 8−11) had main contribution (91.88%) in explaining the main source of morphological variation, while those in otolith contour (Landmark 1−7) just had 8.12%, which reveals that the differences in otolith morphology among the four geographical groups mainly came from the auditory sulcus of otolith. 2) According to the scatter plot of principal component analysis, part of the Haizhou Bay population was significantly divided into one group, while the remaining Haizhou Bay fishing grounds and all other three fishing grounds had highly overlapped and clustered into another group, indicating that there might be two L. polyactis populations in the Southern Yellow Sea area, namely the Southern Yellow Sea-East China Sea group and the Northern Yellow Sea-Bohai Sea group. This also indicates that there were mixed L. polyactis populations in the Haizhou Bay fishing grounds. This may be explained by the long-term egg and larval dispersal process controlled by the current and active migratory routes during feeding and overwintering period. The results verified the potential of otolith morphology in delineating the populations of L. polyactis, providing valuable references for their spatiotemporal distribution.

     

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