罗非鱼对蓝藻的摄食消化及对富营养化水体水华的控制  

Control of cyanobacterial blooms in eutrophication lakes by tilapia

作　　者：陆开宏[1] 金春华[1] 王扬才[1] 

机构地区：[1]宁波大学生命科学与生物工程学院,浙江宁波315211

出　　处：《水产学报》2005年第6期811-818,共8页Journal of Fisheries of China

基　　金：浙江省自然科学基金资助项目(302107;Z505319)

摘　　要：2000年至2003年实验研究尼罗罗非鱼对铜绿微囊藻摄食、消化特性的基础上,在宁波月湖等富营养化景观水体进行了罗非鱼控制蓝藻水华的应用试验.研究表明,罗非鱼对水华蓝藻有很强的摄食与消化能力.25 ℃条件下,罗非鱼鱼种对铜绿微囊藻的平均消化率达67.5%,摄食率则随鱼体体重及水温的升高而增加.1999年至2000年蓝藻泛滥的月湖水体,2001年和2002年先后放养鲢鳙蚌(9.8 g·m-3)和罗非鱼鱼种(3～5 g·m-3)后,蓝藻水华不再出现,浮游藻类年平均细胞数量分别比2000年下降67.5%和79.6%,年平均生物量分别下降48.6%和63.8%;蓝藻占浮游植物生物量的比例由2000年的70.0%分别下降至22.1%和11.2%,水体透明度则由之前的20～50 cm上升至55～137 cm.在已经发生严重蓝藻水华的镇海公园等水体中,放养罗非鱼鱼种 (8～15 g·m-3)20 d左右,水华消失,叶绿素含量和浮游植物数量显著下降,水体透明度明显提高.罗非鱼放养对水体氮、磷等营养盐指标的影响存在较大的不确定性,可能与系统初始的群落结构、营养状态及水体所承受的营养物负荷存在更大的关系.罗非鱼放养应是控制富营养化水体蓝藻水华的理想措施之一.Outbreak of cyanobacteria blooms, with associated unsightly scum and unpleasant odor, occurs regularly in the eutrophication lakes. Using filter-feeding fish is one of the ways to control the blooms. Based on the studies on ingestion and digestion of cyanobacteda Microcystis aeruginosa by tilapia under laboratory conditions, we carded out field testing to use tilapia to control cyanobacteria blooms in Lake Yuehu and other eutrophication lakes in Ningbo, China from 2000 to 2003. The results show that the tilapia were capable of ingesting and digesting large quantity of cyanobacteria. The average digestion rate of Microcystis aeruginosa by fingerling tilapia ranged from 58.6% to 78. 1% at the water temperature of 25℃, and the ingestion rate increased with increasing fish weight and water temperature. Outbreak of cyanobacteria blooms occurred in Lake Yuehu in both 1999 and 2000. The lake was stocked with cultured silver carp, bighead carp and mussel （9.8 g·m^-3） at the beginning of 2001 and cultured tilapia （3 - 5 g·m^-3） in April of 2002. Cyanobacteria bloom has not occurred ever since. From June to October, the average total phytoplankton density decreased from 897.6×10^6 cells· L^-1 in 2000 to 291.7×10^6 cells·L^-1 in 2001 and 183.0×10^6 cells·L^-1 in 2002. The annual average phytoplankton biomass in 2001 and 2002 decreased 48.6 % and 63.8 %, respectively, from that of 2000. The cyanobacterla as proportion of phytoplankton biomass decreased from 70% in 2000 to 22.1% in 2001 and 11.2% in 2002. In the meantime, the water transparency （Secci disk depth） increased from 20 - 50 cm to 55 - 137 cm. Similar results were obtained in some other eutrophication water bodies. For example, at the lake in Zhenghai park, algal bloom disappeared about 20 days after tilapia fingerlings were stocked （8- 15 g·m-3）. The chlorophyll a concentration and phytoplankton productivity declined dramatically whereas the water transparency increased substantially. How the stocked tilapia affects the nutrient （e. g.

关 键 词：罗非鱼 富营养化 蓝藻水华 摄食 消化 生态效应 

分 类 号：S963.213[农业科学—水产养殖]