The feasibility of using environmental DNA to reveal crustacean biodiversity in an estuarine area in Hong Kong

Attributing to the influence of Pearl River and the underwater topology, the seawater in the western Hong Kong is usually low in salinity, turbid and fast flowing. The poor visibility and relatively dangerous condition in the western waters would introduce bias in the collection of underwater inventory data using visual census method in this region. In the present study, the crustacean biodiversity of Hong Kong western waters were studied using molecular technique - Environmental DNA (eDNA), a non-invasive and less labour intensive method. Seawater and sediment samples were collected from three sites in western Hong Kong, with eDNA extracted. Polymerase Chain Reaction (PCR) amplification of genetic marker, Cytochrome Oxidase I (COI), for all the extracted samples were conducted. By applying Illumina High Throughput Sequencing (Miseq) analysis, 51 crustacean species from 34 families were identified in this study by blasting the sequences against the online database, NCBI GenBank. The results showed segregation among samples from different sites. Multivariate analysis, ANOSIM, showed that there is a statistically significant difference among different sites. eDNA dataset revealed in the current study did not demonstrate a high recovery of species on records. Further study will be needed to assess the effectiveness of eDNA in revealing fish biodiversity in marine environment. Copyright © 2019 The Crustacean Society.