珠江三角洲养殖池塘底栖动物群落结构及水质生物学评价

摘要

珠江三角洲是我国主要的水产养殖区域之一.为了解珠江三角洲鱼类养殖池塘底栖动物群落结构,进而评价养殖水体水质状况,于2016年7-8月对6种养殖模式30口池塘底栖动物及其环境因子进行调查.结果表明:1)共采集底栖动物18种,隶属于3门14属,其中寡毛类和水生昆虫均为7种,软体动物为4种.优势种为克拉泊水丝蚓(Limnodrilus claparedeianus)、水丝蚓属一种(Limnodrilus sp.)和摇蚊属一种(Chironomus sp.)等耐污种类.2)6种养殖模式池塘底栖动物平均种类数无显著差异,但其密度和生物量却存在显著差异,杂交鳢Y(杂交鳢幼鱼)和杂交鳢C(杂交鳢成鱼)养殖池塘均显著高于其他4种养殖模式池塘.3)皮尔逊相关分析结果表明,影响珠江三角洲池塘底栖动物密度和生物量的主要因素是总氮(TN)和总磷(TP).两个主要分类群中,寡毛类密度和生物量仅与TN浓度呈显著正相关,而摇蚊幼虫却与TN和TP浓度均呈显著正相关.4)采用Shannon-Wiener多样性指数、Margalef多样性指数和Biotic Index生物指数对6种养殖模式30口池塘水质进行评价,结果表明Shannon-Wiener多样性指数不宜应用于珠江三角洲池塘的水质评价,Margalef多样性指数和Biotic Index生物指数的评价结果均表明杂交鳢Y、杂交鳢C以及草鱼池塘全部处于重度污染,而大口黑鲈S(投喂饲料)、大口黑鲈S+B(投喂饲料+冰鲜鱼类)和罗非鱼池塘大部分处于重度污染,少数处于中度污染.%Pearl River Delta is one of the main aquaculture areas in China.In order to understand the community structures of macrozoobenthos and further assess the water quality in aquaculture ponds,a field investigation of macrozoobenthos and environmental parameters was conducted in 30 ponds with six aquaculture models during July to August 2016.The results showed that a total of 18 species belonging to 14 genera and 3 phyla were identified,and the species number of oligochaeta,aquatic insect,and mollusca was 7,7,and 4,respectively.The dominant taxa of macrozoobenthos were the Limnodrilus claparedeianus,Limnodrilus sp.,and Chironomus sp.,which have strong tolerances to pollution.The average species number among the six model ponds had no significant differences.However,the density and biomass were significantly different,and which were significant higher in two models (juvenile and adult fish,respectively) of hybrid snakehead (Channa maculate ♀ xChanna arguss ♂) than the other four model ponds.Pearson correlation analyses showed that the TN and TP were the main factors influencing the density and biomass of macrozoobenthos in aquaculture ponds of Pearl River Delta.The density and biomass of oligochaeta were only positively correlated with IN,while which of chironomids were significantly affected by TN and TP.The water quality of 30 aquaculture ponds were assessed using Shannon-Wiener index,Margalef index,and Biotic index.It suggested that the Shannon-Wiener index was not appropriate for the assessment of water quality in aquaculture ponds of Pearl River Delta.The assessment results by Margalef and Biotic index showed that all the ponds of grass carp (Ctenopharyngodon idellus) and hybrid snakehead were heavily polluted,while most ponds of large mouth bass (Micropterus salmoides) and tilapia (Oreochromis mossambicus) were heavily polluted and a few ponds were moderately polluted.