象山港蓝点马鲛(Scomberomorus niphonius)摄食习性

Feeding habits of Japanese Spanish mackerel(Scomberomorus niphonius) larvae and juveniles in Xiangshan Bay

2015年4月3日—6月10日利用方形网采集象山港水域仔稚鱼,分析蓝点马鲛(Scomberomorus niphonius)摄食习性及其与饵料生物的相关性。期间共进行10个航次的调查,采集蓝点马鲛仔稚鱼1108尾,体长范围4.0~41.1 mm,其中587尾个体用于摄食分析。结果表明:象山港蓝点马鲛仔稚鱼的饵料生物有11种,其中鱼类仔鱼个体占98.6%,以斑鰶(Konosirus punctatu)、鰕虎鱼(Gobiidae)、鮻(Chelon haematocheilus)等为主要种类;摄食率随生长发育逐渐升高,卵黄囊仔鱼摄食率最低(为20.4%),弯曲期及之后的个体摄食率均在60%以上;蓝点马鲛仔稚鱼口裂较大,占体长的16.4%~25.1%,且与体长呈极显著正相关(P<0.01);随个体生长发育,饵料体长逐渐增大且范围变广,与蓝点马鲛仔稚鱼的体长和口裂长均呈极显著正相关(P<0.01);调查期间饵料生物丰度出现3个波峰,蓝点马鲛仔稚鱼主要出现在饵料生物丰度的第二波峰期间,经Pearson相关分析表明蓝点马鲛仔稚鱼与饵料生物丰度呈显著相关(P<0.05)。

The present study explored the feeding ecology of the larvae and juveniles of Japanese Spanish mackerel（Scomberomorus niphonius） collected from Xiangshan Bay between April 3th and June 10 th in 2015.In order to obtain sufficient quantity of individuals in different development stages,larvae and juveniles were sampled weekly by frame net（1 m×2 m,1.0 mm mesh size）.A total of 1108 individuals were collected across the study,having body length of 4.0-41.1 mm;587 intact specimens among them were used to investigate the feeding ecology of the larvae and juveniles by gut content analysis.A total of 11 prey species were found in guts,and fish larvae were the dominant preys（98.6%）,which mainly consisted of Konosirus punctatus,Gobiidae and Chelon haematocheilus.Except yolk-sac larvae,the feeding incidences were62.0%,81.3%,80.0%,and 86.8% in pre-flexion,flexion,post-flexion larval and juveniles,respectively.The gape-size of larvae and juveniles significantly correlated with its body length,and the rate of the gape-size relative to body length ranged from 16.4% to 25.1%.The mean size of the prey increased accordingly as the predator S.niphonius grew,which also showed significant correlation with body length and gape-size.The average length for prey ranged from 2.6 mm in yolksac larval to 11.2 mm in juveniles.There were three peaks for the density of dominant prey items in Xiangshan Bay,and S.niphonius mainly appeared in the second peak of prey abundance during the study period.The variation of S.niphonius was synchronized with that of prey item density.