鲢鱼放养密度对水体中浮游藻类的影响

Abstract

2013年4~9月调查了山西省永济市温流水良种繁育场鲢鱼放养密度对水体浮游藻类，特别是蓝藻细胞丰度以及溶氧量的影响。两组鱼塘，一组为低密度鲢鱼养殖(21.2 g/m3)，一组为高密度鲢鱼养殖(42.4 g/m3)。调查结果显示：1) 高密度鲢鱼放养鱼塘溶氧高于低密度鲢鱼放养鱼塘；2) 初期水体的浮游藻类总细胞丰度差异不大，但后期鲢鱼高密度放养鱼塘浮游藻类总细胞丰度低于低密度放养鱼塘；3) 初期两种密度鲢鱼养殖池塘中的蓝藻细胞丰度差异不大，后期高密度鲢鱼养殖池塘比低密度鲢鱼养殖池塘中的蓝藻细胞丰度明显降低，在浮游藻类总细胞丰度中所占比例也有同样的变化趋势；4) 两种养殖密度下，后期高密度养殖池塘中优势种有由蓝藻门向其他门类变化的趋势。总体结论，高密度鲢鱼养殖较低密度鲢鱼养殖可以更有效地控制和减少水体中的浮游藻类细胞丰度，特别是蓝藻的细胞丰度，更有利于水质净化，同时也提高了渔产潜力。 An investigation was carried out that the breeding density of Hypophthalmichthys molitrix influenced the cell abundance of phytoplankton, especially Cyanobacteria in Wenliushui Excellent Fish Breeding Grounds, Yongji, Shanxi Province, North China, from April to September of 2013. Two experimental groups were set, which represented low and high breeding density of H. molitrix, and were 21.2 g/m3 and 42.4 g/m3 respectively. The results showed that: 1) the dissolved oxygen of high density breeding ponds was higher than that of low breeding density ponds; 2) the cell abundance of phytoplankton had little difference at first but distinct difference later, and it was obvious lower in high breeding density ponds of H. molitrix than that in low breeding density ponds; 3) the same trend was reflected in Cyanobacteria; 4) compared with the low breeding density ponds, the dominant species had the trend from Cyanobacteria to the other divisions in high density breeding ponds of H. molitrix. In conclusion, the high density breeding of H. molitrix can control the cell abundance of phytoplankton especially Cyanobacteria, and purify water body, and meanwhile, the aquatic productivities are increased.