Re ECF Project: 2013-28

Project Title: Genetic diversity and population structure of freshwater fish in Hong Kong and South China

Applicant: Professor Chu Ka Hou, The Chinese University of Hong Kong

Total Approved Grant: $1,016,460

Duration: 1/3/2015 to 30/11/2017

Project Status/Remarks: Completed

This project aims to facilitate the effective and sustainable conservation management of freshwater ichthyofauna in Hong Kong through:

  1. elucidating the genetic diversity and population structure (including identifying the presence of any cryptic species) in eight indigenous fish species, Schistura fasciolata , Puntius semifasciolatus , Oreonectes platycephalus , Macropodus opercularis , Pseudogastromyzon myersi , Rhodeus ocellatus , Acrossocheilus beijiangensis and Acrossocheilus parallens ; and
  2. confirming the status of two cryptic species and determining their distribution in Hong Kong based on sequence analysis of both mitochondrial and nuclear markers.

Summary of the Findings/Outcomes:
The development of effective conservation requires in-depth understanding on the biodiversity, in which genetic diversity is an important component. The project extensively investigated the genetic diversity and population connectivity of ten indigenous freshwater species (Schistura fasciolata, Pseudogastromyzon myersi, Puntius semifasciolatus, Oreonectes platycephalus, Macropodus opercularis, Rhodeus ocellatus, Acrossocheilus beijiangensis, Acrossocheilus parallens, Rhinogobius duospilus and Parazacco spilurus) in Hong Kong for the first time based on information from both mitochondrial and nuclear DNA markers. By analysing the DNA sequences of over 900 specimens collected from 89 localities, the research team found that the common species (S. fasciolata, P. myersi, P. semifasciolatus, O. platycephalus, R. duospilus and P. spilurus) have high genetic diversity and pronounced population structure. By contrast, the rare species (M. opercularis, R. ocellatus, A. beijiangensis and A. parallens) show extremely low genetic diversity and weak population structure, and thus warrant higher conservation attention. Genetically divergent cryptic lineages/species were discovered in S. fasciolata, R. duospilus and P. spilurus. The population structures of S. fasciolata and P. myersi and R. duospilus are likely shaped by sea-level fluctuations during Late Miocene to Late Pliocene, suggested by the concordance in divergence time of major lineages.