Zhang Chen, Hu Simin, Lin Xianzhi, Huang Hui, Liu Sheng
Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou China.
University of Chinese Academy of Sciences Beijing China.
Ecol Evol. 2025 Jun 4;15(6):e71497. doi: 10.1002/ece3.71497. eCollection 2025 Jun.
Small carnivorous fishes serve as important mesopredators in coral reef ecosystems. However, the habitat and prey availability degradation within these ecosystems has intensified the trend of body size miniaturization and interspecific competition among these species. To better understand the food selection and resource partitioning strategies of mesopredators, we conducted a comprehensive study on the feeding habits of four small carnivorous fish species collected from the coral reefs of the Nansha Islands. This study employed a combination of morphological analysis and molecular identification of gut contents, along with stable isotope analysis. Similar food items, mostly semi-digested/undigested body remains/fragments from crustaceans, fish, and mollusk were detected in the guts of the analyzed fishes. High-throughput sequencing based on DNA barcoding identified approximately 24 taxa belonging to Arthropoda, Chordata, and Mollusca, with Arthropoda being the most abundant prey group, accounting for 82.2%-92% of the total sequences across the four fish species. Stable isotope analysis further revealed that the trophic levels of the four species ranged from 3.4 to 3.6. The results of food overlap analysis based on stable isotopes contrasted with those obtained from high-throughput sequencing, highlighting the distinct characteristics and complementary strengths of these methods. This study broadens the current understanding of the feeding ecology of four carnivorous fish species. The findings reveal that crustaceans are the primary food source for carnivorous fishes in the Nansha Islands, differing from previous assumptions that their diets were predominantly fish-based. Additionally, the differentiated utilization of crustacean resources among these species suggests that marine benthic invertebrates may play a crucial role in supporting mesopredators within degraded coral reef ecosystems, potentially helping to mitigate the environmental stress they face.
小型肉食性鱼类是珊瑚礁生态系统中的重要中型捕食者。然而，这些生态系统内栖息地和猎物可利用性的退化加剧了这些物种体型小型化和种间竞争的趋势。为了更好地理解中型捕食者的食物选择和资源分配策略，我们对从南沙群岛珊瑚礁采集的四种小型肉食性鱼类的摄食习性进行了全面研究。本研究采用了肠道内容物的形态分析和分子鉴定相结合的方法，以及稳定同位素分析。在所分析鱼类的肠道中检测到了相似的食物种类，主要是来自甲壳类动物、鱼类和软体动物的半消化/未消化的身体残骸/碎片。基于DNA条形码的高通量测序鉴定出了大约24个属于节肢动物门、脊索动物门和软体动物门的分类单元，其中节肢动物是最丰富的猎物群体，占这四种鱼类总序列的82.2%-92%。稳定同位素分析进一步表明，这四个物种的营养级范围在3.4到3.6之间。基于稳定同位素的食物重叠分析结果与高通量测序结果形成对比，突出了这些方法的不同特点和互补优势。本研究拓宽了目前对四种肉食性鱼类摄食生态学的认识。研究结果表明，甲壳类动物是南沙群岛肉食性鱼类的主要食物来源，这与之前认为它们的饮食主要以鱼类为主的假设不同。此外，这些物种对甲壳类动物资源的差异化利用表明，海洋底栖无脊椎动物可能在支持退化珊瑚礁生态系统中的中型捕食者方面发挥关键作用，有可能帮助减轻它们面临的环境压力。
