丰、枯水期杭州湾东北部渔业资源多样性及数量分布

为研究不同时期杭州湾渔业资源多样性及生物数量分布特征,利用相对重要性指数、Jaccard相似性系数等分析方法对杭州湾东北部水域渔业资源种类组成、密度分布及多样性指数的空间变化进行分析。结果显示:两时期共捕获40种渔业生物,其中丰水期捕获34种,枯水期捕获22种,两时期Jaccard相似性系数仅为40%,为中等不相似水平(middle nonsimilar level)。丰水期优势种为安氏白虾(Exopalaemon annandalei)和棘头梅童鱼(Collichthys lucidus),枯水期优势种为葛氏长臂虾(Palaemon gravieri)、焦氏舌鳎(Cynoglossus joyneri)、刀鲚(Coilia ectenes)、髭缟虾虎鱼(Tridentiger barbatus)、狭颚绒螯蟹(Eriocheir leptognathus)和日本鼓虾(Alpheus japonicas)。丰水期渔业生物的重量密度为294.82 kg/km2,尾数密度为83.19×103ind/km2,枯水期渔业生物的重量密度为85.76 kg/km2,尾数密度为33.88×103ind/km2。丰水期尾数多样性指数(H')变化范围为0.16~2.35,重量H'变化范围为0.36~2.22,尾数H'与尾数密度呈现显著相关性(P=0.0040.05);枯水期尾数H'变化范围为1.24~2.03,重量H'变化范围为0.81~2.10,尾数H'与尾数密度也呈显著相关性(P=0.0240.05)。研究表明,丰、枯水期杭州湾东北部渔业资源数量分布与种类的洄游习性和环境因子的变化有关,多样性指数偏低,可能预示着杭州湾东北部渔业生物多样性受到严重干扰。

Diversity and density distribution of fishery resources in Northeast of Hangzhou Bay during flood and drought seasons

For studying on diversity and density distribution of fishery resources in Northeast of Hangzhou Bay during drought and flood seasons, the methods of Index of Relative Importance and Jaccard similarity coefficient, etc. were applied in this study to analyze species composition,fish biology density and spatial distribution of diversity index in Northeast of Hangzhou Bay. The results indicated that a total of 40 species were found during drought and flood seasons, including 34 species in flood season, 22 species in drought season. Jaccard similarity coefficient between drought and flood seasons was 40%(middle nonsimilar level). The dominant species in flood season were Exopalaemon annandalei and Collichthys lucidus, and the dominant species in drought season were Palaemon gravieri, Cynoglossus joyneri, Coilia ectenes, Tridentiger barbatus, Eriocheir leptognathus and Alpheus japonicas. Weight density and individual density of fishery biology during flood season were respectively 294.82 kg/km² and 83.19×10³ ind/km², and weight density and individual density of fishery biology during drought season were respectively 85.76 kg/km² and 33.88×10³ ind/km². Individual diversity index(H') during flood season was 0.16-2.35, weight H' was 0.36-2.22, individuals H' were closely related to individual density (P=0.004<0.05); Individual diversity index(H') during drought season was 1.24-2.03, weight H' was 0.81-2.10, individuals H' were closely related to individual density(P=0.024<0.05). The research showed that density distribution of fishery resources in Northeast of Hangzhou Bay during drought and flood seasons was related to species migration habits and environmental factors, and diversity index was a little low, which probably meant that diversity of fishery biology in Northeast of Hangzhou Bay was seriously disturbed.