太湖梅梁湾大型生态控藻围栏内鲢鳙的生长特征

富营养化湖泊围栏养殖鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)控制蓝藻水华在生物操纵示范中得到了广泛应用。在2004和2005年,研究了太湖梅梁湾生态修复区内大型生物控藻围栏中鲢鳙的季节生长特征,分析了影响其生长的因素。结果表明,鲢鳙生长受养殖密度的影响很大,鲢在养殖密度低的2004年和养殖密度高的2005年的日均增重分别为6.07 g和4.30 g,鳙则分别为11.29 g和5.09 g。鳙的生长速度比鲢快,但受密度影响的程度比鲢大。从季节变化来看,鲢属于单峰型生长,生长速度和水温显著正相关;而鳙一年中呈现出2个生长高峰期,分别在5～6月和9～10月,夏季爆发的蓝藻水华对鳙的生长速度有所抑制。为使当年投放的鱼苗在年底能达到出售的商品规格,太湖梅梁湾水域围栏养殖鲢鳙的初始鱼苗投放密度应低于12 g/m3。

The Growth Characters of Hypophthalmichthys molitrix and Aristichthys nobilis in Large Fish Pens in Meiliang Bay of Lake Taihu

Silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) were widely pen-cultured in Chinese eutrophic lakes for the control of cyanobacterial blooms. In 2004 and 2005, we studied the growth characters of pen-cultured silver and bighead carp in the large biomanipulation fish pens in the Meiliang Bay of Lake Taihu. Our results showed that the growth rates of silver and bighead carp were significantly influenced by the stocking density. The average growth rates of silver and bighead carp was 6.07 g/day and 11.29 g/day in 2004 with a low stocking density, and 4.30 g/day and 5.09 g/day in 2005 with a high stocking density, respectively. The growth speed of bighead carp was higher than silver carp. Growth rate of silver carp showed a single peak in one year, which was significantly related with water temperature. However, growth rate of bighead carp showed two peaks during May to Jun and September to October. The outbreak of cyanobacterial blooms seemed to hinder the growth of bighead carp in summer. In order to reach the commercial specification in one year culture, the initial stocking density of fingerlings should less than 12 g/m3 at the beginning of the year in the Meiliang Bay of Lake Taihu.