河蟹幼蟹培育池浮游动物群落结构及动态

Dynamics and Community Structure of Zooplankton in Juvenile River Crab Breeding Ponds

针对河蟹幼蟹培育池塘的渔业生态环境质量状况,以幼蟹培育池和水源区的浮游动物为材料,研究了其种类组成、密度、生物量和多样性。共检测到浮游动物37种,其中优势种12种。幼蟹培育池浮游动物的密度、生物量和多样性指数均高于水源区。枝角类密度总体呈先上升后下降趋势,前期幼蟹培育池枝角类密度显著高于水源区(P<0.05);桡足类密度逐渐上升,后期幼蟹培育池桡足类密度显著高于水源区(P<0.05);轮虫密度逐渐下降,整个时期幼蟹培育池轮虫密度与水源区之间均无显著差异(P>0.05)。浮游动物生物量变化趋势与密度变化趋势基本相同。幼蟹培育池和水源区浮游动物的多样性指数在大多数时间并无显著差异(P>0.05)。结果表明,生态养殖池塘有净化水体的作用,水质明显优于水源区。幼蟹培育池浮游动物种类组成较丰富,群落关系趋向平衡和稳定。温度和食物是影响幼蟹培育池浮游动物群落变动的主要原因。

The river crab,Eriocheir sinensis,is a specialty in China and deeply loved by people. In recent years,the breeding scale expands gradually and the production improves constantly. In 2012,the national production was 714 400 tons.Now,the river crab breeding industry has entered an ecological efficiency stage. The new breeding model is to plant a lot of aquatic weeds in river crab culture ponds,keeps the ecological balance of water,and makes the river crab industry on the path of sustainable development.Previous studies found that the aquatic weeds had purification effect on water quality,the water quality in eco-culture area is better than that in the water source area.Moreover,zooplankton is an important component of the water ecosystem.It is the high-quality natural bait for juvenile river crab and is of very high economic value.At the same time,zooplankton plays an important role in keeping the ecological balance,forming the food chain and adjusting the water self-purification in ponds.In order to scientifically evaluate the fishery ecological environment quality condition in juvenile river crab breeding ponds,the species composition,density,biomass and diversity of zooplankton in juvenile river crab breeding ponds and the water source area were analyzed. Totally,37 species of zooplankton were identified,and 12 species were dominant.The average density,biomass and diversity index of zooplankton in juvenile river crab breeding ponds were higher than in the water source area.The average Cladocera density in general presented a downward trend after rising firstly,and the average Cladocera density in juvenile river crab breeding ponds was significantly higher than in the water source area in early period（ P〈0.05）.The average Copepoda density kept a rising trend,the average Copepoda density in juvenile river crab breeding ponds was significantly higher than in the water source area in later period（ P〈0. 05）. The average Rotifera density presented a gradually falling trend,the average Rotifera density had no significant difference between that in juvenile river crab breeding ponds and that in the water source area during the entire process（ P〉0.05）.The average biomass change trend of zooplankton and the trend of density change were basically the same.In the most of time,the diversity index of zooplankton had no significant difference between that in juvenile river crab breeding ponds and that in the water source area（ P〉0.05）. The results showed that eco-culture ponds have the effect of purifying water body,the water quality is better than that in the water source area.The zooplankton species and numbers increased after the water of source flowed into juvenile river crab breeding ponds.The zooplankton species composition of juvenile river crab breeding ponds was richer,the community relations trended to balance and stability.Temperature and food were the principal environmental factors to the zooplankton community changes in juvenile river crab breeding ponds.