大亚湾黑棘鲷的摄食习性

为了解黑棘鲷(Acanthopagrus schlegeli)在大亚湾生态系统食物网结构中的地位和作用, 2018 年 3 月至 2019 年 1 月逐月在大亚湾采集黑棘鲷样本, 分析黑棘鲷的食性组成、摄食强度、生态位宽度以及食性随季节和体长变化的趋势。结果表明, 大亚湾黑棘鲷饵料生物组成主要包括藤壶、鱼类、贝类、蟹类、虾类、星虫类、头足类、 水生植物等 8 个类群, 相对重要性指数百分比(IRI%)表明藤壶是最重要的饵料类群(IRI%为 42.41%), 其次依次是鱼类、贝类、蟹类、虾类、星虫类、头足类和水生植物。大亚湾黑棘鲷全年均有摄食, 摄食强度随季节变化显著, 其中胃饱满指数以春、冬季较高, 夏、秋季较低; 而空胃率则以夏季显著高于其他季节。不同季节食性差异明显, 春季主要以藤壶为食, 夏季主要以鱼类为食, 秋季主要以贝类为食, 冬季则主要以藤壶和鱼类为食, 影响食性组成随着季节变化的主要因子为水温、食物资源的可获得性等; 黑棘鲷体长越长, 越倾向于摄食大个体饵料, 摄食强度也越大, 营养生态位宽度先宽后窄。本研究结果将为今后黑棘鲷的保护和人工养殖提供理论依据。

Feeding habits of Acanthopagrus schlegeli in the Daya Bay

To understand the status and role of Acanthopagrus schlegeli in the food web structure of the Daya Bay ecosystem, the diet composition, feeding intensity, and niche width of A. schlegeli were analyzed, and the trend of dietary changes with seasons and body length was discussed based on annual and monthly sampling data from March 2018 to January 2019. Results showed that the food composition of A. schlegeli in the Daya Bay was mainly divided into eight groups, including barnacles, fish, shellfish, crabs, shrimp, sipuncularia, cephalopods and aquatic plants. The percentage index of relative importance (IRI%) indicated that barnacles were the most important group (IRI%: 42.41%) in the feeding habits of A. schlegeli, followed by fish, shellfish crabs, shrimps, sipuncularia, cephalopods, and aquatic plants. The A. schlegeli eats throughout the year in the Daya Bay, and the feeding intensity varied significantly with the seasons. The stomach fullness index was higher in spring and winter and lower in summer and autumn. The emptiness percentage in summer was significantly higher than that in other seasons. It mainly feeds on barnacles in spring, fish in summer, shellfish in autumn, and barnacles and fish in winter. Water temperature and the availability of food resources were the main factors influencing the diet composition in different seasons. The feeding habits of A. schlegeli changed with the body length, and for the feeding intensity, the size of the food eaten increased with the body length. Moreover, the niche width first widens and then narrows as individuals grow larger.