环境DNA在水生生态系统生物量评估中的研究进展

通过环境DNA技术 (Environmental DNA, eDNA) 检测珠江中下游鱼类生物多样性，探索珠江中下鱼类多样性监测和保护的新途径。2023年2月在珠江中下游设置了桂平、藤县、封开、德庆、肇庆和九江共6个采样点，通过水样采集及过滤、eDNA提取、遗传标记扩增及测序和数据库比对分析等流程检测鱼类多样性。结果表明，6个采样点共检测出30种鱼类，隶属于4目10科27属，其中土著鱼类26种，外来种4种。较已有传统调查数据新检出2种鱼类：美丽沙鳅 (Botia pulchra) 和齐氏罗非鱼 (Oceochromis zillii)。鱼类优势种为子陵吻鰕虎鱼 (Rhinogobius giurinus)、瓦氏黄颡鱼 (Pelteobagrus vachellii)、鲢 (Hypophthalmichthys molitrix)、尼罗罗非鱼 (O. nilotica)、齐氏罗非鱼、南方波鱼 (Rasbora steineri) 和鲤 (Cyprinus carpio)。根据Shannon指数和Simpson指数显示，eDNA检测九江和桂平站点的鱼类多样性最高，藤县的最低。作为一种新的检测方法，eDNA技术可用于快速检测珠江中下游鱼类的多样性及分布，在实际应用中可将eDNA技术与传统的监测方法相结合，以提供更全面的鱼类生物多样性数据信息。

Challenges to saving China's freshwater biodiversity: fishery exploitation and landscape pressures

To explore new ways for observing and protecting fish species diversity in the middle and lower reaches of the Pearl River, we used eDNA technology to detect fish species diversity in that river section. Six sampling localities, namely Guiping, Tengxian, Fengkai, Deqing, Zhaoqing and Jiujiang, were set up in February 2023. The fish diversity was detected by eDNA metabarcoding analysis that includes water collection, water filtration, eDNA extraction, genetic marker amplification, sequencing and bioinformatic analyses. The results show that 30 fish species had been detected in 6 sampling sites, belonging to 4 orders, 10 families and 27 genera, in which 26 were native species and 4 were non-native species. Compared with traditional survey reports, two new species (Botia pulchra and Oceochromis zillii) were detected. Rhinogobius giurinus, Pelteobagrus vachellii, Hypophthalmichthys molitrix, O. nilotica, O. zillii, Rasbora steineri and Cyprinus carpio were found at each sampling site, indicating that these species are the dominant species in the survey area. According to Shannon index and Simpson index, the fish diversity was highest in Jiujiang and Guiping, while lowest in Tengxian. As a new detection method, eDNA technology can efficiently investigate the fish biodiversity and distribution in the middle and lower reaches of the Pearl River. To sum up, eDNA technology can be combined with traditional fish resources monitoring methods to provide more comprehensive data information on fish species diversity.