为探究万山群岛鱼类群落的营养结构特征, 构建万山群岛渔业生物简要食物网, 于 2021 年秋季(9 月)利用稳定同位素技术分析了万山群岛主要渔业生物的营养结构特征, 并计算了其营养结构的量化指标。结果表明, 万山群岛海域鱼类 δ¹³C 值变化范围为−21.23‰ (鲻 Mugil cephalus)~−14.00‰ (黑边布氏鲾 Eubleekeria splendens), 均值为 (−16.96±0.41)‰, δ15N 值变化范围为 9.93‰ (卵形鲳鲹 Trachinotus ovatus)~14.83‰ (截尾白姑鱼 Pennahia anea), 均值为(12.52±0.34)‰, 鱼类的营养级变化范围为 2.54~3.98, 平均营养级为 3.30。鱼类的 δ¹³C 变幅(CR)为 7.23, δ¹⁵N 变幅(NR)为 4.90, 凸多边形总面积(TA)为 23.64, 矫正后的标准椭圆面积(SEAc)为 3.73, 平均离心距离(CD)为 1.30, 平均最邻近距离(MNND)和平均最邻近距离标准差(SDNND)均为 0.24。基于碳氮稳定同位素值可将万山群岛的鱼类划分为 3 个类群, 分别是浮游食性鱼类 4 种(3.57%)、底栖食性鱼类 7 种(6.25%)和低级肉食性鱼类 101 种(90.18%)。 Bayesian 混合模型计算万山群岛海域鱼类的食物主要来源于浮游动物(zooplankton), 其贡献率为 62.54%, 其次是藻类贡献率为 25.28%。本研究初步构建了万山群岛鱼类连续营养谱, 对掌握万山群岛海域食物网与营养结构特征有重要意义, 可为万山群岛生态系统的保护与管理提供有力的数据支撑。

To explore the nutritional structure and subsequently construct a brief food network of fish communities in the Wanshan Islands, this study analyzed the main nutritional characteristics of the key fishery organisms using stable isotope technology in autumn (September) of 2021, while simultaneously calculating various quantitative indicators. As a result, the δ¹³C value of fish from the Wanshan Islands ranged from –21.23‰ (Mugil cephalus) to –14.00‰ (Eubleekeria splendens), with a mean value of (–16.96±0.41)‰. Additionally, the δ¹⁵N value ranged from 9.93‰ (Trachinotus ovatus) to 14.83‰ (Pennahia anea), with a mean value of (12.52±0.34)‰. The trophic levels of these fish varied from 2.54 to 3.98, with an average trophic level of 3.30. Furthermore, the δ¹³C range (CR), δ¹⁵N range (NR), total area (TA), standard ellipse area (SEAc), mean distance to centroid (CD), mean nearest neighbor distance (MNND), and standard deviation of nearest neighbor distance (SDNND) of the fish were 7.23, 4.90, 23.64, 3.73, 1.30, and 0.24, respectively. Based on the stable isotope values of carbon and nitrogen, the fishes in the Wanshan Islands could be divided into three main groups: 4 species (3.57%) of planktivorous fishes, 7 species (6.25%) of benthic fishes, and 101 species (90.18%) of low-grade carnivorous fishes. According to the Bayesian mixed model, the main food source of fish in the Wanshan Islands is zooplankton with contribution rate of 62.54%, followed by algae with a contribution rate of 25.28%. This study constructed a novel continuous trophic spectrum of the fishes in the Wanshan Islands that was of great significance in examining the characteristics of food web and trophic structure and could provide strong data support for the protection and management of the Wanshan Islands ecosystem.

S931

国家重点研发计划项目(2019YFD0901204, 2019YFD0901201)； 广东省基础与应用基础研究基金项目(2019B1515120065)；广东省基础与应用基础研究重大项目(2019B030302004-05)； 中国水产科学研究院基本科研业务费项目(2020TD16)；中国水产科学研究院南海水产研究所中央级公益性科研院所基本科研业务费专项(2021SD04, 2019TS28)