春、夏季杭州湾口门区鱼类资源数量与多样性的时空分布特征

Fish Stock Density and Diversity: Spatial and Temporal Distribution in the Outlet of Hangzhou Bay in Spring and Summer

为研究不同季节杭州湾口门区鱼类资源数量分布及多样性时空变化,利用扫海面积法、Shannonwiener多样性指数(H')和Spearman相关性分析等方法对该片水域鱼类种类数、资源密度和多样性的时空分布特征进行分析。结果显示春、夏季杭州湾口门区共捕获22种鱼类,春季12种,夏季20种,种类数更替具有统计学差异(Q=5.333,P=0.021<0.05)。春季鱼类的质量密度为17.80 kg/km^2,尾数密度为2.32×103ind./km^2,夏季鱼类的质量密度为234.35 kg/km^2,尾数密度为21.64×103ind./km^2。春、夏季鱼类资源的密度也具有显著性差异。春季鱼类质量H'平均值为0.98±0.43,尾数H'平均值为1.28±0.50,夏季鱼类质量H'平均值为1.17±0.45,尾数H'平均值为1.16±0.38。Spearman相关性分析表明,春季鱼类尾数H'与种类数(P=0.000<0.05,R=0.912)及个体密度(P=0.011<0.05,R=0.758)均呈显著相关性,夏季鱼类质量H'(P=0.033<0.05,R=0.673)和尾数H'(P=0.009<0.05,R=0.772)均只与种类数显著相关。研究表明,春、夏季杭州湾口门区鱼类资源数量分布与海洋性鱼类的洄游习性有关,多样性的空间分布受长江口冲淡水影响。

To study the spatial and temporal distribution of fish stock density and diversity in the outlet ofHangzhou Bay during different seasons, sweep area method, Shannon- wiener diversity index（H＇） andSpearman correlation analysis were applied to variety analysis of fish species and density. The results showedthat 22 species including 12 species in spring and 20 species in summer were found in the outlet of HangzhouBay. There were significant differences of fish species between spring and summer（Q=5.333, P=0.0210.05）.Weight density and individual density of fishes were 17.80 kg/km^2 and 2.32 × 103 ind./km^2 in spring,respectively, and were 234.35 kg/km^2 and 21.64×103ind./km^2 in summer, respectively. There were significantdifferences of fish density between spring and summer. The average weight H＇ and individual H＇ were 0.98±0.43 and 1.28 ± 0.50 in spring, respectively, and were 1.17 ± 0.45 and 1.16 ± 0.38 in summer, respectively.Spearman correlation analysis indicated that individual H＇ was closely related to fish species（P=0.0000.05,R=0.912） and individual density（P=0.0110.05, R=0.758） in spring, while only fish species was closelyrelated to weight H＇（P=0.0330.05, R=0.673） and individual H＇（P=0.0090.05, R=0.772） in summer. The research indicated that the spatial and temporal distribution of fish stock density was related to the migratoryhabit of marine fishes in the outlet of Hangzhou Bay during spring and summer, and the spatial distribution offish stock diversity was probably influenced by the diluted water of the Yangtze River.