象山港三种不同养殖方式对浮游动物群落的影响

摘要

为探究不同营养类型养殖方式对半封闭海湾浮游生态系统的影响,于2015年在象山港的鱼类网箱养殖、牡蛎筏式养殖和海带筏式养殖3种养殖区内外分别进行大、中型和中、小型浮游动物群落及相关环境因子的四季研究.结果显示,牡蛎养殖区内大、中型浮游动物群落结构变化明显,夏、秋季优势种太平洋纺锤水蚤的优势度下降,冬季优势种腹针胸刺水蚤的优势度上升;网箱养殖区内浮游动物群落变化不明显,变化主要为大、中型浮游动物优势种,春、冬季腹针胸刺水蚤的优势度下降,秋季优势种种类组成变化明显;海带养殖区内浮游动物群落和优势种变化均不明显.此外,3种养殖方式对浮游动物的生物量、丰度和α多样性均未产生明显影响.结合象山港的水文特征和养殖区内外的环境因子,研究表明,牡蛎养殖区浮游动物群落变化是牡蛎滤食行为和铁港水交换能力差的综合结果,而浮游动物优势种变化可能与水体总磷含量较高有关;因目前网箱养殖规模小且西沪港水动力条件较好,网箱区内局部环境和浮游动物的变化较小;海带养殖因面积小且仅春、冬季养殖,不足以对水质和浮游动物产生影响.此外,本研究显示不同环境中,大、中型浮游动物群落结构的变异较中、小型浮游动物明显,这可能与中、小型浮游动物群落的稳定性较高有关.%To explore the effects of three different aquacultures on planktonic ecosystem in semi-closed bay, the macro- and meso-zooplankton community, meso- and micro-zooplankton community and 12 kinds of associated environmental factors were studied inside and outside the fish cage aquaculture, kelp raft aquaculture, and farms in Xiangshan Bay via seasonal cruises during 2015.The results demonstrate that: compared with the control areas in the oyster farm, the macro- and meso-zooplankton community composition changed obviously, and the dominance of Acartia pacifica declined during summer and autumn, while that of Centropages abdominalis went up in winter;in the fish farm, the dominant species of macro- and meso-zooplankton changed, with the dominance of Centropages abdominalis declining during spring and winter, and dominant species composition changing obviously in autumn; however, in the kelp farm, there was no marked change in zooplankton community;moreover, the effects of the three different aquacultures on biomass, abundance and α-diversity of zooplankton community were nonsignificant.Analyzing the above results, combined with the hydrological characteristics in Xiangshan Bay and the environmental factors inside and outside the farms, we considered, the change in zooplankton community was a comprehensive result of oyster filter-feeding behavior and the poor water exchange capacity in Tie Harbor, and the zooplankton dominant species variation might relate to elevated total phosphorus content in the farm; in our study, fish cage aquaculture effects on environment and zooplankton were less, mainly due to the small aquaculture scale recently and good hydrodynamic condition in Xihu Harbor; the kelp aquaculture was inadequate to influence the water quality and zooplankton community, because of its small cultural scale and short cultural period every year (only in spring and winter).In addition, the variation in macro- and meso-zooplankton was more obvious than that in meso- and micro-zooplankton, which may be related to the higher stability in meso- and micro-zooplankton community.