克氏原螯虾池塘放养密度对浮游生物群落的影响

Effect of stocking density of Procambarus clarkii on plankton community in pond

研究了在克氏原螯虾和河蟹3个放养密度水平下浮游生物群落的变动情况。结果表明:可能由于浮游动物的摄食对浮游植物产生影响,二者生物量的消长在大多数池塘中都呈负相关。随着养殖密度的增加,浮游植物生物量增加,而浮游动物有所减少;前者的优势种群由硅藻门和绿藻门变为裸藻门、蓝藻门和甲藻门等有害藻类,后者由枝角类、哲水蚤和剑水蚤等大型浮游动物变为轮虫、原生动物和无节幼体等小型浮游动物为主。浮游动植物比值与虾蟹放养密度呈显著的负相关性。在考虑生态效益和经济效益最适的情况下,以中密度养殖最为适宜。

This paper studied the variations of plankton community in ponds, in which Procambarus clarkii and Eriocheir sinensis were stocked in three densities. The results showed that because zooplankton fed on phytoplankton, their quantities were in negative correlation in the most ponds. With the increasing of density, the biomass of phytoplankton increased and the forms of Euglenophyta, Cyanophyta, Pyrrophyta instead of Bacillariophyta and Chlorophyta became dominant group in the high density groups, but zooplankton＇s biomass decreased, supported by Protozoa, Rotife and Nauplius. The biomass ratio of zooplankton/phytoplankton showed significant negative correlation with stocking density of shrimp and crab. The results of this study indicated that the medium stocking density was optimum so as to give consideration to the ecological benefit and economic benefit.