小黑山岛人工鱼礁区许氏平鲉和大泷六线鱼的营养生态位研究

Study on Trophic Niches of Sebastes schlegelii and Hexagrammos otakii in the artificial reef area of Xiaoheishan Island

以小黑山岛人工鱼礁区的2种典型恋礁鱼类许氏平鲉(Sebastesschlegelii)和大泷六线鱼(Hexagrammosotakii)为研究对象,利用碳、氮稳定同位素技术分析了其在 2016 年春秋两季的生态位重叠及宽幅变化情况。许氏平鲉的δ^13C 值在春季显著大于大泷六线鱼,而在秋季则无明显差异;δ^15N值在春秋两季均显著大于大泷六线鱼。频率分布方面,许氏平鲉的δ^13C值频率分布范围始终大于大泷六线鱼,而其δ^15N 值频率分布的季节变动幅度小于大泷六线鱼,表明许氏平鲉具有更广泛的食物来源、占据较为稳定的营养级层次,大泷六线鱼则具有明显的摄食选择性且所居营养级层次波动剧烈。此外,许氏平鲉与大泷六线鱼仅在秋季出现营养生态位的重叠,表明在人工鱼礁区群落中许氏平鲉与大泷六线鱼之间存在种间食物竞争;而许氏平鲉春秋两季的营养生态位宽幅均大于大泷六线鱼,说明许氏平鲉较大泷六线鱼对食物资源的利用和竞争能力更强。

This study analyzed the niche overlap and wide variation between two typical reef fish species, Sebastes schlegelii and Hexagrammos otakii, from an artificial reef area of Xiaoheishan Island, during spring and autumn. The δ^13C value of S. schlegelii was significantly higher than that of H. otakii in spring, while there was no difference between the two species in autumn. Moreover, the δ^15N value of S. schlegelii was significantly greater than that of H. otakii in both spring and autumn. The frequency distribution of S. schlegelii δ^13C values was always greater than that of H. otakii, while the seasonal variation of the δ^15N frequency distribution was less than that of H. otakii. We concluded that S. schlegelii utilized a wide range of food sources and occupied a stable trophic level, while H. otakii had a narrower preference for food, and the trophic level it occupied fluctuates dramatically. In addition, there was an overlap of trophic niches between the two species only in autumn, while at other times S. schlegelii had a higher and wider trophic niche than H. otakii. In conclusion, we found there was interspecific competition between S. schlegelii and H. otakii in the artificial reef community, and S. schlegelii had a superior ability to utilize food resources.