凡纳滨对虾养殖池塘及外河道中后生浮游动物群落结构差异及其影响因素

Differences in metazooplankton community structure and its influencing factors in Litopenaeus vannamei aquaculture ponds and outer channels

摘要:

为了解凡纳滨对虾养殖对池塘后生浮游动物群落结构的影响，于2021年5月上旬至10月上旬在上海市奉贤区某养殖场及其外河道进行了16次调查，分析了后生浮游动物的物种组成及优势种、密度、生物量和生物多样性。共鉴定出后生浮游动物33种（轮虫23种、枝角类6种、桡足类4种），优势种6种（轮虫4种、枝角类1种、桡足类1种），其中针簇多肢轮虫（Polyarthra trigla）和广布中剑水蚤（Mesocyclops leuckarti）为养殖塘和外河道共同优势种。Jaccard相似性分析表明，养殖塘与外河道后生浮游动物物种组成整体上处于中等相似水平。总体上养殖塘后生浮游动物密度、生物量、优势种数和多样性指数均高于外河道。养殖塘和外河道中Shannon-Wiener多样性指数H’均值分别为1.56±0.48和1.55±0.34，表现为中度污染；Gleason-Margalef物种丰富度指数D均值分别为0.81±0.32和0.76±0.33，表现为重度污染；养殖塘总体处于中度富营养水平，外河道水体则处于轻度富营养水平。Pearson相关性分析表明，养殖塘后生浮游动物群落结构与水温（WT）、总氮（TN）、总磷（TP）、高锰酸盐指数（COD）和浮游植物中的隐藻门具有显著相关性，而外河道后生浮游动物群落分布与WT、溶解氧（DO）、叶绿素a （Chl.a）、COD、悬浮物（SS）和浮游植物中的隐藻门、裸藻门和甲藻门具有显著相关性。冗余分析（Redundancy analysis，RDA）表明，TP和COD是影响凡纳滨对虾养殖塘后生浮游动物群落结构的关键因子，而浮游植物中的隐藻属、DO、和TN则是影响外河道后生浮游动物群落的主要环境因子。研究结果表明凡纳滨对虾养殖池塘环境因子对后生浮游动物群落结构具有显著影响，且明显区别于外河道环境因子对后生浮游动物群落结构的影响，揭示了对虾养殖生产会显著改变天然水体中后生浮游动物群落结构，对凡纳滨对虾的生态养殖和水质调控具有重要意义。

Abstract:

In order to understand the impact of Litopenaeus vannamei culture on the community structure of metazooplankton in ponds, 16 surveys were conducted in an aquaculture farm and its outer channels in Fengxian District, Shanghai from early May to early October in 2021. Metazooplankton species composition and dominant species, density, biomass and biodiversity were analyzed. A total of 33 metazooplankton species (including 23 species of Rotifers, 6 species of Cladoceras, and 4 species of Copepods) were identified in the study. Among them, Polyarthra trigla and Mesocyclops leuckarti were the common dominant species in both aquaculture ponds and outer channels. Jaccard similarity analysis indicated that the species composition of metazooplankton in aquaculture ponds and outer channels were moderately similar. Generally speaking, the density, biomass, dominant species and diversity index of metazooplankton were higher in aquaculture ponds than those in outer channels. The mean values of Shannon-Wiener diversity index H' were 1.56±0.48 and 1.55±0.34 in aquaculture ponds and outer channels, respectively, which showed moderate pollution, and the mean values of Gleason-Margalef species richness index D were 0.81±0.32 and 0.76±0.33, respectively, which showed heavy pollution; Aquaculture ponds were at middle eutrophic level, while outer channels were at light eutrophic level. Pearson correlation analysis showed that the metazooplankton community structure in aquaculture ponds was significantly correlated with Water Temperature(WT), Total Nitrogen(TN), Total Phosphorus(TP), Permanganate index(COD)and phytoplankton(Cryptophyta),while the outer channels metazooplankton community distribution were significantly correlated with WT, Dissolved Oxygen(DO), Chlorophylla(Chl.a), COD, Suspended Solids(SS)and phytoplankton(Cryptophyta, Euglena and Dinophyta)Correlation. Redundancy analysis(RDA)showed that TP and COD were the key factors affecting the metazooplankton community structure in Litopenaeus vannamei aquaculture ponds. Phytoplankton(Cryptoplankton), DO, and TN were the main environmental factors that affected the metazooplankton community in outer channels. The results show that the environmental factors in Litopenaeus vannamei aquaculture ponds have significant impacts on the community structure of metazooplankton, which is obviously different from the influence of environmental factors on the community structure of metazooplankton in outer channels. It reveals that the shrimp aquaculture production will significantly change the community structure of metazooplankton in aquaculture ponds compared to natural water, which is of great significance to the ecological aquaculture of Litopenaeus vannamei and the regulation of water quality.