江苏近海北部海域春季鱼类群落结构的年间变化

Interannual changes in fish community structure in the northern part of the coastal waters of Jiangsu Province,China in spring

根据2009—2014年在江苏近海北部海域(34.00!—35.13!N,119.40!—121.50!E)的底拖网调查数据,结合综合性指标和多元统计分析等方法研究了该海域的鱼类群落结构随时间的变化.结果表明:江苏近海海域共有鱼类68种,相对资源量波动较大,站位平均渔获质量的变化范围为0.75~1.62 kg·h^(-1),站位平均渔获尾数显著下降,变化范围为203~370 ind·h^(-1).2009—2014年江苏近海的鱼类群落平均营养级指数在3.58~3.72,2009—2010年相对较低,2011—2014年在3.70以上波动.2009—2014年鱼类群落的平均个体大小在2.93~11.18 g之间波动上升,变化趋势与平均营养级基本一致.聚类分析和非度量多维标度排序分析表明,研究期间大致分为2009—2010和2011—2014年两个年份组.组间分歧种主要有尖海龙、小头栉孔虾虎鱼和玉筋鱼等.对前后两个年份组的分析表明,中上层、浮游生物食性鱼类优势度增加,冷温种和本地种优势度下降.表明江苏近海海域鱼类群落结构发生了较为明显的演替.针对演替规律提出了渔业管理的建议,为渔业资源的合理利用提供理论参考.

Based on the data collected from the bottom trawl surveys in the coastal waters of northern Jiangsu Province from 2009 to 2014, multivariate statistical analysis and other integrated indices were used to analyze the variation in the community structure of fish assemblage over time in the waters. The results showed that 68 species had been caught in the coastal waters of northern Jiangsu Province. There were significant fluctuations in the relative density of fish resources. The mean catch mass per site ranged from 0.75 to 1.62 kg·h-1, and the mean catch individuals per site showed significant decrease in the survey period ranging from 370 to 203 ind·h-1. The mean trophic level （MTL） index varied between 3.58 and 3.72 from 2011 to 2014, being relatively low in 2009-2012 and fluctuating around 3.70 in 2011-2014. The mean body mass of fish community increased from 2.93 to 11.18 g between 2009 and 2014, showing a similar tendency with that of MTL index. Cluster analysis and MDS showed that the six survey years could be divided into two subgroups of 2009-2010 and 2011-2014. The main discriminating species were Syngnathus acus,Ctenotrypauchen microcephalus and Ammodytes personatus for the two subgroups. Further study showed that the pelagic and planktivorous fishes had gradually increased in dominance while cold temperate species and indigenous species had decreased over the years. It was suggested that fish communities in the coastal waters of northern Jiangsu Province underwent a remarkable succession. Advices for the fisheries management in the waters were provided according to the succession pattern, which might contribute to the sustainable utilization of fishery resources.