人工模拟条件下青海湖裸鲤自然繁殖环境条件需求研究

为对青海湖裸鲤(Gymnocypris przewalskii)的自然繁殖需求条件进行定量研究, 实验结合青海湖裸鲤自然产卵场原位生境调查, 通过室内人工模拟构建产卵环境诱发野生亲鱼自然繁殖, 解答可控环境中青海湖裸鲤自然繁殖的环境需求。结果表明, 青海湖裸鲤自然繁殖发生与水温、水深、流速、光照及底质因素密切相关, 其中卵石河床质较细砂等底质环境可显著提升自然交配诱导率及繁殖效果; 在合适的底质条件下, 青海湖裸鲤自然繁殖的适宜条件: 水深为0.15—0.2 m、流速为0.2—0.4 m/s、水温为10.8—14.3℃; 15D﹕9L比例的光周期有利于促进青海湖裸鲤自然繁殖的发生。在人工模拟环境中, 水深≥0.45 m、流速≥0.8 m/s、温度≥17℃或≤6℃、全光照等环境中未观测到自然繁殖活动的发生, 这些被认为是其自然繁殖环境的限制条件。研究阐明了可控环境中青海湖裸鲤野生亲鱼自发产卵繁殖的环境需求, 构建人工模拟产卵环境技术, 为自然产卵场生境调查评估、改进人工繁育模式提供技术支撑和新思路。

ENVIRONMENTAL REQUIREMENTS OF NATURAL REPRODUCTION OF GYMNOCYPRIS PRZEWALSKII UNDER ARTIFICIAL SIMULATED CONDITIONS

The natural reproduction of fish is a physiological response process under the stimulation of specific environment. The environment condition of fish spawning habitat is very important for the reproduction of fish. Currently, there is no quantitative study on the demand for natural reproduction of Gymnocypris przewalskii. In combination with the in situ investigation of the natural spawning grounds of G. przewalskii, artificial spawning environment was simulated in the laboratory to answer the environmental requirement for the natural reproduction of G. przewalskii. The results showed that the occurrence of spawning activities of G. przewalskii was closely related to the water temperature, water depth, flow rate, light and substrate factors. The results showed that the natural mating induction rate and reproductive effect can be significantly increased in the substrate of pebble than that in the sand or the mud substrate. The suitable range of the water depth, water velocity, water temperature for spawning is 0.15—0.2 m, 0.2—0.4 m/s, and 10.8—14.3℃, respectively. Increasing the everyday’s dark cycle is beneficial for the occurrence of spawning. Under the controlled environment, when the water depth is above 0.45 m, water velocity is more than0.8 m/s, and the water temperature is higher than 17℃ or lower than 6℃, there will be no spawning activities, which maybe the limit conditions required for the natural reproductive.This study elucidated the environmental parameters for the spontaneous spawning and reproduction of G. przewalskii in a controlled environment, and successfully constructs a simulated spawning environment. It can provide technical supports and new ideas in the natural spawning habitat investigation and contribute for improving the artificial breeding technologies of G. przewalskii.