胭脂鱼亲本放流长江后的运动特征

胭脂鱼(Myxocyprinus asiaticus Bleeker)为国家二级保护动物,近年来的资源量已明显衰退。为保护和恢复胭脂鱼种群资源,开展了增殖放流工作。本研究采用超声波标志及固定站监测的方法对2018年3月在长江上游宜宾段放流的10尾胭脂鱼亲本(5雌 5雄,体重12.5 kg±5.4kg)的运动特征进行了跟踪监测。结果显示,有 4 尾个体在放流后存在短暂上行运动,其余个体持续下行。放流胭脂鱼的平均迁移距离为(456.2±335.8) km,最远达到了宜昌秭归江段。监测期末, 5尾分布在宜宾江津江段, 4 尾分布在江津忠县江段,另有1尾分布在巴东秭归江段。放流胭脂鱼的平均对地运动速度为(2.31±2.03) km/h,最大下行速度和最大上行速度分别为 35km/h和 1.04 km/h,下行运动速度高于上行运动速度。平均运动速度在不同的江段间无明显差别,但在不同的时间段存在差别,放流后20d内的运动速度高于40d以后。胭脂鱼放流后的平均栖息水深为(6.24±4.84)m,越往下游,其栖息水深越深。个体在单日内的栖息水深存在较大变幅。根据监测结果,提出了增加放流胭脂鱼亲本数量和放流点的建议。

Movement of the matured Chinese sucker (Myxocyprinus asiaticus) after releasing in the Yangtze River

Chinese sucker is under national first class protection, the resources has declined significantly in recent years. In order to restore the natural population, releasing and enhancement have been carried out. In this study, 10 tagged Chinese sucker (5 females and 5 males, average body weight 12.5 kg ±5.4 kg) were released in the Yibin reaches of the upper Yangtze River in March 2018, the movement characteristics of the releasing fishes were monitored by 20 fixed stations for nearly 500 d. The monitoring results showed that there were 4 individuals with short-term upward movement and the remaining individuals continued to downward movement. The average moving distance of the released fishes was 456.2 km ±335.8 km, the longest movement was to the Zigui reaches. At the end of the monitoring period, 5 individuals were distributed in the Yibin-Jiangjin reaches, 4 individuals were distributed in the Jiangjin-Zhongxian reaches, and 1 individual was distributed in the Badong-Zigui reaches. The average speed of the released fishes was 2.31 km/h ±2.03 km/h, and the maximum downward and upward speed were 35 km/h and 1.04 km/h, respectively. The downward speed was higher than the upward speed. The average moving speed did not differ between different reaches, but there were differences in time periods. The moving speed within 20 d after releasing was higher than 40 d later. The average habitat depth of the Chinese sucker was 6.24 m±4.84 m. Along with the downward movement, the released individuals chose deeper inhabitation. The individual had a large variation of habitat depth in a single day. Based on the monitoring results, increasing the number of released matured Chinese sucker and adding more releasing sites were suggested.