海州湾秋季小眼绿鳍鱼摄食习性的空间异质性

研究海州湾小眼绿鳍鱼摄食习性的空间异质性,对于海州湾食物网构建和资源保护具有重要意义。根据2011及2013-2016年秋季在海州湾海域进行的渔业资源底拖网调查数据,结合小眼绿鳍鱼（Chelidonichthys spinosus）的空间分布特征及其胃含物样品的分析结果,研究了海州湾小眼绿鳍鱼的摄食热点海域及其摄食习性的空间异质性。结果表明,小眼绿鳍鱼是海州湾秋季底层鱼类群落中的优势鱼种,且各年均主要分布在海州湾35 °N附近及以北海域。细螯虾（Leptochela gracilis）、戴氏赤虾（Metapenaeopsis dalei）和疣背宽额虾（Latreutes planirostris）是小眼绿鳍鱼最重要的三种饵料生物。研究发现,海州湾小眼绿鳍鱼的摄食热点海域主要集中在30 m等深线附近,且尚未呈现出明显的年间变化趋势。根据各站位小眼绿鳍鱼食物组成的相似性,将调查海域划分为两个区域,即近岸区和远岸区,近岸区小眼绿鳍鱼的体长和体重均显著小于远岸区（P < 0.05）,小眼绿鳍鱼在近岸区主要摄食细螯虾和疣背宽额虾,在远岸区则主要摄食戴氏赤虾。近岸区小眼绿鳍鱼的空胃率显著小于远岸区（P < 0.05）,条件指数显著大于远岸区（P < 0.05）,平均胃饱满指数大于远岸区,但尚未呈现出显著差异（P > 0.05）,表明海州湾秋季小眼绿鳍鱼的摄食习性存在明显的空间异质性。

Study on spatial heterogeneity in feeding habits of Chelidonichthys spinosus in Haizhou Bay during autumn

Spatial heterogeneity in fish feeding ecology is the basis for understanding energy flow and material circulation, and for constructing food webs in marine ecosystems. In this study, based on the survey data collected by bottom trawls in Haizhou Bay during the autumn of 2011 and 2013-2016, combined with the spatial distribution pattern and analysis of stomach contents of Chelidonichthys spinosus, the feeding hotspots and spatial heterogeneity in feeding habits of C. spinosus were studied. The results showed that C. spinosus had become one of the dominant fish species in the fish community and mainly distributed in the north of 35°N in Haizhou Bay. Leptochela gracilis, Metapenaeopsis dalei, and Latreutes planirostris were the most important prey species for C. spinosus. Feeding hotspot analysis showed that the feeding hotspots of C. spinosus were mainly distributed around the 30 m isobath in Haizhou Bay but did not show clear variation between years. According to the similarity in the dietary composition of C. spinosus at each station, the surveyed area was divided into two areas, i.e., an inshore area and offshore area. The body length and body weight of C. spinosus in the inshore area were significantly lower than those in the offshore area (P < 0.05). Feeding habit analysis showed that L. gracilis and L. planirostris were the primary prey species for C. spinosus among a total of 56 prey species in the inshore area. In contrast, C. spinosus mainly fed on M. dalei among 64 species present in the offshore area. The overlap index between the two areas is 0.55, which is not significant. The percentage of empty stomachs of C. spinosus in the inshore area was significantly lower than that in the offshore area (P < 0.05), and the condition index was significantly higher in the inshore area (P < 0.05). The mean stomach fullness index in the inshore area was higher than that in the offshore area, but there was no significant difference (P > 0.05). This study showed that there was obvious spatial heterogeneity in the feeding habits of C. spinosus. Therefore, we conclude that it is essential to consider spatial heterogeneity when studying the feeding ecology of fish.