北部湾带鱼的摄食习性

2008年8月至2009年9月，对北部湾带鱼逐月渔获物胃含物进行鉴定和统计分析，研究其摄食习性.结果表明：北部湾带鱼捕食种类包括鱼类、头足类、底栖甲壳类以及浮游动物等,属于广食性动物.优势种类有少鳞犀鳕(37.99%)、蓝圆鲹(16.42%)和中国毛虾(10.03%).蓝圆鲹和尖吻小公鱼全年在全湾带鱼的食物中均有出现,是重要的饵料指标种类.摄食强度与饱满指数的季节差异十分显著(P<0.001),食物多样性无显著季节性差异(P>0.05)，秋季最高,全年平均为1.97.聚类分析表明,北部湾带鱼在达到50%性成熟肛长值(190 mm)时,饵料由幼鱼的以小型浮游动物、中上层鱼类及甲壳类为主向成鱼的以较大型鱼类和头足类为主转换.

Feeding habits of Trichiurus lepturus in Beibu Gulf of South China Sea

From August 2008 to September 2009,the feeding habits of Trichurus lepturus L.in Beibu Gulf of South China Sea were studied by monthly sampling and stomach content analysis.In study area,T.lepturus was euryphagous,which fed on fish,cephalopoda,benthic crustacean,and zooplankton,etc.,among which,Bregmaceros rarisquamosu,Decapterus maruadsi,and Acetes chinensis were the main prey components,accounting for 37.99%,16.42%,and 10.03%,respectively.D.maruadsi and Anchoviella heteroloba appeared throughout the Beibu Gulf all year round,and could be served as the index species for the migration and fishing ground distribution of T.lepturus.The indices feeding intensity and stomach fullness differed significantly among seasons(P <0.001); while the index prey diversity had no significant seasonal difference(P > 0.05),which peaked in autumn and had an annual average value of 1.97.Cluster analysis revealed that when the preanal length of T.lepturus was 190 mm,i.e.,at 50% of maturity length,a clear diet shift happened,from small zooplankton,pelagic fishes,and crustacean for the juveniles to predomi nantly larger fish and cephalopoda for the adults.