南海西沙毗邻海域四种眶灯鱼的营养生态位

为探究南海西沙毗邻海域中层鱼类(mesopelagic fish)的食性及中层鱼类在生态系统中的营养生态位, 本研究以南海西沙毗邻海域的 4 种中层鱼: 亮眶灯鱼(Diaphus splendidus)、短距眶灯鱼(D.mollis)、灿烂眶灯鱼(D.fulgens) 和吕氏眶灯鱼(D.luetkeni)为研究对象, 运用碳氮稳定同位素技术对 4 种眶灯鱼的营养级、营养生态位以及主要食物来源进行研究。结果显示: (1) 4 种眶灯鱼 δ¹⁵N 范围为 8.31‰~11.08‰, δ¹³C 范围为−21.88‰~−18.19‰; (2) 4 种眶灯鱼营养级存在差异, 吕氏眶灯鱼(3.75)＞亮眶灯鱼(3.63)＞灿烂眶灯鱼(3.57)＞短距眶灯鱼(3.41); (3) 灿烂眶灯鱼的营养生态位宽度最大, 对饵料资源的利用能力较强, 食源丰富。亮眶灯鱼的营养生态位宽度最小, 对某些饵料生物选择性较强, 摄食具有专一性; (4) 4种眶灯鱼之间存在一定的食物资源摄取利用的竞争关系, 但吕氏眶灯鱼与短距眶灯鱼不存在竞争; (5) 贝叶斯混合模型表明浮游动物是 4 种眶灯鱼的主要饵料生物。本研究揭示了西沙毗邻海域 4 种眶灯鱼的主要食物来源和营养生态位特征, 为研究中层鱼类的食性特征以及营养结构关系提供了基础数据, 对深入开展中层鱼类对海洋生态系统能量流动与物质循环等研究具有意义。

Trophic niches of four Diaphus species in the adjacent waters of the Xisha area of the South China Sea

To explore the feeding habits and trophic niche of mesopelagic fish in the adjacent sea area of Xisha in the South China Sea, this study focused on four mesopelagic fish: Diaphus splendidus, Diaphus mollis, Diaphus fulgens, and Diaphus luetkeni. Carbon and nitrogen stable isotope technique was used to investigate the trophic levels, trophic niches, and primary food sources of these four species. The results showed that: (1) The δ¹⁵N values of the four species ranged from 8.31‰ to 11.08‰, and the δ¹³C values ranged from –21.88‰ to –18.19‰; (2) There were differences in trophic levels among the four species, with D. luetkeni (3.75) ＞ D. splendidus (3.63) ＞ D. fulgens (3.57) ＞ D. mollis (3.41); (3) D. fulgens had a largest trophic niche width and a stronger ability to utilize bait resources. The trophic niche width of D. splendidus was the smallest, and which had strong selectivity and feeding specificity towards bait organisms; (4) There was a certain competitive relationship in food resource intake among the four species, but there was no competition between D. luetkeni and D. mollis; (5) Bayesian mixture models indicated that zooplankton was the main food source for the four mesopelagic fish. This study revealed the main food sources and trophic niche characteristics of the four mesopelagic fish species in the adjacent sea area of Xisha, providing basic data for the study of the feeding characteristics and nutritional structure relationships of mesopelagic fish, and was significant for further research on the energy flow and material cycling in marine ecosystems.