漓江各类仔稚鱼对环境因子的适应性研究

Study on the adaptability of some kinds of larva and juveniles to environmental factors in Lijiang River

(目的)为漓江鱼类多样性保护与资源可持续利用提供理论依据。(内容)以漓江中游近岸水域仔稚鱼为对象,研究漓江中游流域仔稚鱼对水文及水环境特征的选择性和适应性,探讨的关键因子与鱼类的早期发育过程的相关关系。(方法)在漓江中游桂林市区河段近岸水域选择设3个定点采样站,现场测定水温、溶解氧和p H等水质指标,并从网站获取流量和降雨量等水文数据。(结果)调查共采集仔稚鱼样本7406尾。经鉴定为15种,隶属于3目8科14属,其中,鲤科鱼类物种数和个体数均最多,主要优势种为高体鳑鲏、宽鳍鱲。仔稚鱼渔获数量主要集中在5月、6月、7月和8月,显著高于9月(P<0.01)。相关性分析结果表明,对仔稚鱼数量影响的关键环境因子为溶解氧、水量和水温。(建议)上游水库运营后需及时进行生态调度保证漓江生态需水,从保护鱼类资源角度,漓江禁渔期延长至7月。

Objective to provide a theoretical basis for the conservation of fish diversity and sustainable utilization of resources in the Lijiang River.Taking the larvae and juveniles of the middle reaches of Lijiang River as the object,we studied the selectivity and adaptability of the larvae and juveniles to the hydrology and water environment characteristics,and discussed the correlation between the key factors and the early development of fish. In the middle reaches of the Lijiang River,3 fixed-point sampling stations were selected in the nearshore waters of the Guilin,and the water quality indexes such as water temperature,dissolved oxygen and p H were measured,and the hydrological data such as flow rate and rainfall were obtained from the website. A total of 7406 specimens of juvenile fish were collected. Identified as 15 species,belonging to 3 orders,8 families and 14 genera,among them,the Cyprinid fish species number and individual number were the most dominant species are Rhodeus ocellatus,Rhodeus ocellatus,Hemiculter leucisculus,Zacco platypus. The number of fish and juveniles was mainly concentrated in May,June,July and August,which was significantly higher than that in September(P < 0. 01). The results of correlation analysis showed that the key environmental factors affecting the number of larva and juvenile fish were dissolved oxygen,water and water temperature. Operation shall be carried out in time after the upstream reservoir ecological operation to ensure the Lijiang river ecological water demand,from the perspective of the protection of fish resources,Lijiang River fishing ban extended to July.