不同混养鱼类和投喂方式对鱼蚌综合养殖水体化学特征的影响

摘要

选用草鱼(Ctenoparyngodon idellus)、银鲫(Carassius gibelio)、鲢(Hypopthalmichthys molitrix)、鳙(Aristichthys nobilis)作为本研究的混养鱼类，通过围隔实验检验了不同混养鱼类组合(草鱼+鲫+鲢+鳙或鲢+鳙)和配合饲料投喂方式(投喂或不投喂)对三角帆蚌(Hyriopsis cumingii)养殖水体化学特征的影响，实验为期155 d.结果表明，实验设计的混养鱼类组合可显著影响鱼蚌综合养殖水体的 Ca2+、总碱度(Alk)、总硬度(HT)和总磷(TP)水平；投喂配合饲料可显著影响 Ca2+、Alk、HT、氨氮(TAN)、TP 和化学耗氧量(CODMn).采用混养组合(草鱼+鲫+鲢+鳙)且投喂配合饲料的围隔内溶氧(DO)水平和透明度(SD)较低， Ca2+、HT、TN、TP、TAN 和 CODMn 水平较高；采用混养组合(鲢+鳙)且不投喂的围隔内 DO 和 SD 水平较高，而 Ca2+、HT、TN、TP、TAN 和 CODMn 水平较低.随养殖时间延长，各组围隔内 Ca2+水平下降， TN、TP、TAN 和 CODMn 水平升高.实验期间， DO 与 SD 水平呈正相关； DO 和 SD 与 TAN、TN、TP、Ca2+和 CODMn 水平呈负相关.因此，鱼蚌综合养殖中，控制 CODMn 和 TAN 浓度，维持 Ca2+稳定及较高的 DO 水平是水质管理的基本目标.%Integrated culture is widely used in freshwater pearl mussel (Hyriopsis cumingii) farming; however, water chemistry characteristics relating to H. cumingii farming are poorly understood. To assess the effects of co-cultured fish (grass carp, gibel carp, silver carp and bighead carp or silver carp and bighead carp) and formu-lated fish feed supplement (with or without feed supplement) on water chemistry characteristics, a 155-day field experiment was carried out in land-based enclosures. Four treatments including GGSB-F (co-cultured fish grass carp, gibel carp, silver carp and bighead carp were fed formulated feed), GGSB-NF (co-cultured fish grass carp, gibel carp, silver carp and bighead carp were not fed formulated feed), SB-F (co-cultured fish silver carp, and bighead carp were fed formulated feed) and SB-NF (co-cultured fish silver carp and bighead carp were not fed formulated feed) were established. The results indicated that the combination of co-cultured fish species could significantly affect Ca2+, total alkalinity (ALK), total hardness (HT) and total phosphorus (TP), while the feed supplement regime affected Ca2+, ALK, HT, ammonia (TAN), TP and chemical oxygen demand (CODMn). Dis-solved oxygen (DO) and secchi depth (SD) were lower, while Ca2+, HT, total nitrogen (TN), TP, TAN and CODMn were higher in the GGSB-F enclosures. Conversely, DO and SD were higher, but Ca2+, HT, TN, TP, TAN and CODMn were lower, in the SB-NF enclosures. During the experimental period, Ca2+ decreased, while TN, TP, TAN and CODMn increased. DO and SD were positively correlated with each other and negatively to the levels of TAN, TN, TP, Ca2+ and CODMn. Therefore, water quality management programs should include controlling the concen-tration of TAN and CODMn at the levels below the critical values, and maintaining Ca2+ and DO at high and con-stant levels.