Key Laboratory of Freshwater Aquatic Genetic Resources (Ministry of Agriculture), Shanghai Ocean University, Shanghai, 201306, China.
Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, 201306, China.
Environ Sci Pollut Res Int. 2022 Aug;29(37):56658-56675. doi: 10.1007/s11356-022-19923-3. Epub 2022 Mar 26.
It is a common practice to improve the water environment of rivers and lakes in China by the enhancement and releasing (EAR) of silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) for biomanipulation. However, the quantity of bighead carp and its effect on water quality and plankton community have been the focus of debate among ecologists. Herein, in order to more accurately simulate the environmental conditions of lakes, we selected earthen ponds with large areas adjacent to Lake Qiandao from May to August in 2016 to study the responses of water quality condition and plankton community to a gradient of bighead carp stocked alone. Experimental groups with different densities of carp stocked were set as follows: 12.1 (LF), 23.5 (MF), and 32.5 g/m (HF), and a control group with no fish (NF). Results showed that total phosphorus (TP) in the fish-containing groups considerably decreased, and the lowest chlorophyll-a concentration (chl-a) was detected in the MF group. The biomass accumulation of the crustacean zooplankton was suppressed after carp was introduced, but the diversity, richness, and evenness of the crustacean zooplankton were weakly affected, except in the HF group. Phytoplankton biomass especially that of cyanobacteria was grazed rapidly by fish in the MF and HF groups and biodiversity indices were considerably increased in the fish-containing groups, especially in the late stages of the experiment. At a fish stocking density of 23.5-38.8 g/m, the highest efficiency in controlling cyanobacteria and promoting water condition was achieved, and the impact on zooplankton diversity was weak. Our results indicated that bighead carp can be included in the EAR of lakes and reservoirs, but the optimal density of bighead carp stocking should be carefully considered.
在中国，通过增强和释放（EAR）鲢鱼（Hypophthalmichthys molitrix）和鳙鱼（Hypophthalmichthys nobilis）来进行生物操纵以改善河流和湖泊的水环境是一种常见做法。然而，鳙鱼的数量及其对水质和浮游动物群落的影响一直是生态学家争论的焦点。在此，为了更准确地模拟湖泊的环境条件，我们选择了 2016 年 5 月至 8 月毗邻千岛湖的大面积土塘，研究了单独放养鳙鱼对水质条件和浮游动物群落的响应。设置了不同密度的鲤鱼放养实验组，分别为：12.1（LF）、23.5（MF）和 32.5 g/m（HF），以及无鱼的对照组（NF）。结果表明，含鱼组的总磷（TP）含量显著降低，MF 组的叶绿素-a 浓度（chl-a）最低。引入鲤鱼后，甲壳类浮游动物的生物量积累受到抑制，但甲壳类浮游动物的多样性、丰富度和均匀度受到的影响较弱，除了在 HF 组。浮游植物生物量，特别是蓝藻的生物量在 MF 和 HF 组中被鱼类迅速摄食，鱼类含量较高的组的生物多样性指数显著增加，尤其是在实验的后期。在 23.5-38.8 g/m 的放养密度下，对蓝藻的控制和水条件的改善效果最佳，对浮游动物多样性的影响较弱。我们的研究结果表明，鳙鱼可以被纳入湖泊和水库的 EAR 中，但应仔细考虑鳙鱼放养的最佳密度。
