[关键词]
[摘要]
根据2008年11月—2009年9月期间对南海北部湾拖网渔获物中二长棘犁齿鲷采样所得的生物学资料以及胃含物分析相关数据，应用氮稳定同位素技术对北部湾二长棘犁齿鲷的食物组成、摄食习性、营养级等进行研究。结果发现，二长棘犁齿鲷在北部湾海域广泛摄食，包括中上层鱼类、底栖鱼类、甲壳类和头足类等，鉴定到种的饵料生物有23种，以鱼类为主要饵料生物，占79.74%，主要有麦氏犀鳕、康氏小公鱼、粗纹鲾等，其中麦氏犀鳕所占比例最大，每月均有出现，为58.38%；甲壳类和头足类分别占10.86%、6.97%；根据IRI%分析可知，体长在30～59 mm时主要以小型饵料生物浮游动物为食，而60 mm及以上个体则主要以大型饵料鱼类和底栖无脊椎动物为食，有食性转换现象；饱满指数（RI）有显著的体长变化（P<0.05），随性腺发育变化也较明显（P<0.05）；氮稳定同位素比值δ15N的范围为12.009×10-3～16.007×10-3，营养级随体长和月份的变化均不显著，根据饵料质量百分比及δ15N估算得出北部湾二长棘犁齿鲷营养级平均值分别为3.1和3.7。
[Key word]
[Abstract]
Based on the monthly samples caught by bottom trawls in the Beibu Gulf of the South China Sea from November 2008 to September 2009,the biological information and stomach contents were collected for analysis of feeding habits.The stable isotope analysis was also used to study the prey category,trophic level and ontogenetic feeding habits of P.edita.The results showed that P.edita preyed widely in the Beibu Gulf,including twenty-three species such as small pelagic and bottom fishes,benthic crustacean,cephalopoda and so on.Among them,fishes account for 79.74%.The dominant fish prey was Bregmaceros macclellandii which appeared every month,comprising 58.38% of total food weight.Crustacean and cephalopoda account for 10.86% and 6.97%.The trophic shift was found in P.edita according to the index of relative importance(IRI%).Those P.edita whose standard length ranged from 30 mm to 59 mm mainly feed on small zooplankton,while those with standard length greater than or equal to 60 mm mainly feed on large forage fish and benthic invertebrates(shrimps,crabs,and cephalopodas).The average repletion index significantly changed with the standard length(P<0.05),so did the gonad maturity index(P<0.05).The vacuity coefficient also significantly changed with the standard length(P<0.05),but there was no significant difference in gonad maturity alteration.The nitrogen stable isotope ratios were from 12.009×10-3 to 16.007×10-3.The trophic levels of P.edita calculated from δ15N did not differ notably with the standard length and month shift.The average trophic level was calculated by prey weight percentage and δ15N and it was 3.1 and 3.7,respectively.
[中图分类号]
[基金项目]
国家自然科学基金项目（41376158）；近海典型渔业水域增殖潜力与环境修复评价技术研究与应用（2012 BAD18B01）；广东省自然科学基金（S2012040007813）；广东海洋大学大学生创新创业训练项目（1056613038）
