环境DNA技术在宜昌江段四大家鱼自然繁殖中的应用

本研究通过环境DNA(eDNA)技术的样品采集及DNA提取方法,采用微滴式数字PCR(ddPCR)技术检测了长江干流宜昌江段不同水层、不同断面四大家鱼的eDNA浓度,分析了eDNA浓度变化与卵苗密度的关系,探讨了利用eDNA技术监测四大家鱼自然繁殖情况的可行性。结果表明: 与传统调查结果相比,四大家鱼的eDNA浓度与卵苗密度呈极显著相关,浓度最大值与卵苗峰值的出现时间较为一致,利用eDNA技术可以预判家鱼集群产卵行为的发生。连续两年的断面eDNA浓度检测认为,渔洋溪上游4.5 km和下游1 km为家鱼产卵场。该范围位于传统方法预估的胭脂坝下至红花套的产卵场范围内。这说明eDNA技术作为一种新兴的生态调查方法,可更为准确地判定有一定种群规模的鱼种的分布情况,因此具有很好的应用前景。

Application of environmental DNA technology in natural reproduction of the four major Chinese carps in Yichang section of Yangtzi River,China

We explored the sample collection and DNA extraction method of environmental DNA (eDNA) technique. Droplet digital PCR (ddPCR) was used to detect the eDNA concentration of the four major Chinese carps in different water layers and different cross-sections of Yichang section of Yangtze River trunk stream. We analyzed the relationship between eDNA concentration and density of egg and fry, and explored the feasibility of using eDNA technique to monitor the natural reproduction of the four major Chinese carps. Compared with the results from traditional survey methods, the eDNA concentration of the four major Chinese carps was extremely significantly correlated with egg and fry density. The maximum concentration was consistent with the peak occurrence time of egg and fry, suggesting that eDNA technique could predict the fishcrowd behavior for spawning. The investigation of cross-section eDNA concentration during two consecutive years suggested that the range of fish spawning ground was 4.5 km upstream to 1 km downstream of Yuyangxi. The predicted spawning ground was located within the range estimated by traditional methods from the lower part of Carmine Dam to Honghua Tuo. Our results indicate that eDNA technique, as a new ecological investigation method, could more accurately determine the distribution of fish with a certain population size, and thus with a good application prospect.