LB 2-11 - Application of environmental DNA metabarcoding for identifying the fish diversity in urban streams

Background/Question/Methods:

Accurate and continuous biological monitoring is important to understand the impacts of environmental change. Especially, the composition of fish species is known to reflect the surrounding environment in streams. The environmental DNA (eDNA) tool that has been actively applied to monitoring is an appropriate methodology to evaluate the urban environment in detail and efficiently. This study applied eDNA metabarcoding with Mi-fish universal primer in a fine spatial scale (about 2km) to identify ichthyofauna and estimate the species richness (number of detected species) as the alpha-diversity in urban streams. eDNA sampling was conducted in October 2020 at the Anyang stream network (As) and in July 2021 at the Yeouido saetgang ecological park (Ys). Anyang Stream is a tributary of the Han River and Saetgang is a creek that flows between the mid-channel bar in the Han River. The two study areas have the common property that they are ecologically restored urban streams.

Results/Conclusions:

After refining the species list, the total number of eDNA reads 3,202,626 and 3,592,132 in Anyang stream and Yeouido, respectively. In 31 sites of AS, 13 families and 35 species were detected while 12 families and 35 species were detected in 7 sites of Yeouido. Cyprinidae (As: 74.7%, Ys: 97.1%) representing the largest number of species (As: 17 species, Ys: 15 species) accounted for a high proportion at the family level in both study areas. At the same time, P.parva (As: 29.5%. Ys: 87.6%) represented a high proportion and was estimated as the dominant species in both study areas. The alpha diversity of the Anyang stream was a minimum of 5 species and a maximum of 28 species (Mean ± SD: 12.1±4.6) while that of Yeouido was a minimum of 16 species and a maximum of 26 species (Mean ± SD: 21.3±2.8). Even in the dense selection of eDNA sampling sites, alpha diversity differed from site to site, clarifying the fish species distribution and their proportion in urban streams. This indicated that it is necessary to select a dense study site for a more accurate evaluation of ichthyofauna in the urban stream.