闽江口主要渔获鱼类的生态位宽度与重叠

根据2015年闽江口4个季度月(1、5、8、11月)的渔业资源底拖网调查资料,通过相对重要性指数确定主要渔获鱼类,对主要渔获鱼类的生态位宽度、生态位重叠进行分析.结果表明: 4个航次总共渔获鱼类137种,隶属16目37科,以鲈形目、鲱形目、鲽形目和鲀形目等为主.主要渔获鱼类有15种,其中优势种6种,分别为六指马鲅、龙头鱼、白姑鱼、鹿斑仰口鲾、短舌鳎和凤鲚,其余9种为重要种.时空生态位宽度值达到1以上的种类有7种,从大到小依次为短舌鳎、棘头梅童鱼、鹿斑仰口鲾、六丝钝尾虾虎鱼、赤鼻棱鳀、凤鲚、龙头鱼.主要渔获鱼类的生态位变动在闽江口受季节变化的影响比较明显.闽江口主要渔获鱼类种对的时空生态位重叠达有意义水平的种对占比较高,达81.9%,其中重叠显著的有6个种对,说明闽江口主要渔获鱼类间在时空二维上的分布普遍相似,在资源利用上存在竞争关系.时空生态位重叠值最大的种对为日本绯鲤-沙带鱼,重叠值最小的种对为日本绯鲤-棘头梅童鱼,时空生态位重叠受季节变化的影响比较明显.

The breadth and overlap of ecological niche of major fish species in the Minjiang River Estuary,China.

Based on the seasonal bottom trawl surveys in the Minjiang River Estuary in 2015, the breadth and overlap of ecological niche of major fish species were analyzed. Those fish species were identified based on the index of relative importance (IRI). A total of 137 species belonging to 37 families and 16 orders were collected. Fifteen major fish species were determined by the IRI, including six dominant species Polydactylus sextarius, Harpadon nehereus, Pennahia argentata, Secutor ruconius, Cynoglossus abbreviates, Coilia mystus, and nine important species Collichthys lucidus, Amblychaeturichthys hexanema, Upeneus japonicas, Lagocephalus spadiceus, Pampus argenteus, Larimichthys crocea, Thryssa kammalensis, Takifugu oblongus, Lepturacanthus savala. Seven species whose spatio-temporal niche breadth was higher than 1 in a declining order were C. abbreviates, C. lucidus, S. ruconius, A. hexanema, T. kammalensis, C. mystus, H. nehereus. The ecological niche of major fish species in the Minjiang River Estuary showed obvious seasonal dynamics. The percentage of species pairs with spatio-temporal niche overlap at the meaningful level was as high as 81.9%. Six species pairs reached significant ecological niche overlap, indicating that major fish species had similar distribution at the spatial and temporal scales and the existence of resource utilization competition. The species pairs of U. japonicus-L. savalawas had the highest spatio-temporal niche overlap value, whereas U. japonicus-C. lucidus had the lowest niche overlap value. The spatio-temporal niche overlap of major fish species in the Minjiang River Estuary had substantial seasonal variation.