高密度养殖鳑鲏鱼对水体营养盐浓度和浮游植物群落的影响

Effects of intensive Rhodeus sinensis culture on both nutritive salts and phytoplankton of water body

以本地优势种中华鳑鲏(Rhodeus sinensis)为试验对象,设成鱼和稚鱼两组处理,研究了其对水体营养盐浓度和浮游植物群落的影响。结果表明:养殖鳑皱鱼后水体中的总氮(TN)、氨氮(NH_3-N)和总磷(TP)等营养盐浓度明显增高,水质由试验始期的Ⅱ类标准恶化至劣V类,其影响程度以成鱼处理最高;浮游植物的群落结构发生一定改变,生物多样性有所降低,密度和生物量明显增加,各处理均以大体积的衣藻为优势种,对照则以小体积的蹄形藻为优势种。鳑鲏鱼作为清澈水体的优势种鱼类,种群密度过高会造成水体营养盐升高并导致浮游植物生物量加大,成为恶化水质的隐患。

Taking local dominant species rose bitterling Rhodeus sinensis as the test materials,this paper analyzed the fish effects on water nutrient concentrations and phytoplankton communities by setting two treatments,i.e.,adult group and juvenile group.The results showed that after adding bitt-erling R .sinensis ,water nutrient,i.e.,total nitrogen,ammonia nitrogen and total phosphorus concen-trations obviously increased,water quality deteriorated from Grade II to worse than Grade V,and a-dult showed a higher effect.Phytoplankton community structure presented some change,i.e.,biodi-versity decreased,while density and biomass significantly increased.Two treatments with bitterling fish were dominated by large-bodied Chlamydomonas ,and the control group dominated by small-bod-ied Kirchneriella .Therefore,as dominant fish of clear water,excessively high bitterling population density would result in the increment of both water nutrient concentrations and phytoplankton bio-mass,which would become the potential danger of water quality deterioration.