基于流刺网调查的雷州湾游泳生物群落结构分析

根据2014年11月~2015年8月在雷州湾开展的4个航次的流刺网调查数据,分析了游泳生物多样性指数的相关性、相对资源丰度及其影响因子。共鉴定游泳动物113种,隶属于5纲16目49科86属;其中鱼类(82种)和软甲纲(27种)分别占出现总种类数的72.5%和23.9%。种类的丰度排序结果显示,重要性居前10位的种类中,近底层鱼类和中上层鱼类各2种,甲壳类6种。该海域群落多样性水平总体较高,由湾内向湾口海域呈递增趋势;分类多样性指数(Δ)与Shannon-Wiener多样性指数(H')、Pielou均匀度指数(J')均显著相关(Pearson test,P0.01),能更全面地反映游泳生物群落特征。基于RAD的建模分析表明,Mandelbrot模型拟合优度最佳(AIC=485),初步推断该群落总体处于生态竞争占优势的动态平衡。基于广义线性模型的单位捕捞努力量渔获质量(BPUE)、单位捕捞努力量渔获尾数(NPUE)与环境因子分析表明:1)水体溶解氧(DO)极显著影响BPUE(P0.01),而溶解氧、水温及季节变动与水温交互作用显著影响NPUE(P0.05)。2)流刺网的网具长度、站位的地理位置差异对BPUE、NPUE的影响均不显著(P0.05)。调查海域湾内、湾中和湾口的渔业资源群落结构的季节、空间差异较小,仅NPUE的分布存在显著季节波动(P0.05)。

Community structure of nekton in Leizhou Bay using gillnetting

The seasonal gillnetting nekton surveys were conducted in Leizhou Bay during November 2014 and August 2015 , and the diversity, relative abundance of the nekton community and the structuring roles of environmental factors were analyzed. Results show that a total of 113 species were identified to five classes, 16 orders, 49 families and 86 genera, of which the fishes (82 species) and Malacostraca (27 species) accounted for 72. 5% and 23. 9% of the catch, respectively. Among the top 10 important fishing species, there were too pelagic and benthic fishes, and six crustacean species. The diversity indicators was relatively high, increasing from the inner to the mouth of the bay, and the taxonomic diversity (TD, A) was related with the Shannon-Wiener indices (H') and Pielou eveness indices (J') by Pearson test significantly (n = 12, P<0.01), and the TD better described the community characteristics. The modeling of rank abundance distribution(RAD) shows that the Mandelbrot model fitted the abundance of nekton species best with the Akaike's information criterion value of 485, indicating that the nekton community was possibly at a state of equilibrium with higher competition between species. The general linear modeling of biomass per unit of effor(BPUE) and nu bers per unit effort(NPUE) with 11 environmental variables show that the dissolved oxygen (DO) had significant effects on BPUE(P<0.01); the DO, water temperature and its interactions with seasons all affected NPUE significantly (P <0.05). Neither the length of gillnets nor the geographical variation between sites had significant effects on the BPUE or NPUE (P>0.05). In conclusion, there was no evident geo graphical and seasonal difference among the inner, iddle and mouth of nekton community based on gillnetting in Leizhou Bay, except for the significant effect of seasons on the NPUE (P<0.05) .