Re ECF Project: 2009-33

Project Title: Genetic Diversity and Population Differentiation of Freshwater Fish in Hong Kong

Applicant: Prof. CHU Ka Hou of The Chinese University of Hong Kong

Total Approved Grant: $854,440

Duration: 1/10/2010 to 31/3/2013

Project Status/Remarks: Completed

The project aims to elucidate the genetic diversity and population differentiation of six indigenous fish species based on DNA sequence analysis. This project is a pioneer and baseline study on the population genetics of local freshwater fish. By constructing the first comprehensive genetic database for the local fish fauna, this project will facilitate effective and sustainable conservation management of freshwater ichthyofauna in Hong Kong, and lay a solid foundation for further related studies.

Summary of the Findings/Outcomes:
Analyses on mitochondrial control region and cytochrome b reveal diverse population genetic patterns in the six species studied. Macropodus hongkongensis and Rhinogobius giurinus show no genetic structure among populations. For the remaining species, different degrees of genetic divergence and population structuring are observed. R. duospilus appears to be the most genetically diverse fish among the species studied, with four distinct lineages of high genetic divergence (max. 5.6% in the two markers). Two of the lineages show restricted distribution in Lantau Island and Hong Kong Island respectively. Divergent lineages are also found in Parazacco spilurus (8%), in which two distinct lineages with discrete distribution are recovered, with one restricted to the eastern part of the New Territories. Moreover, population structuring is evident within each lineage. In Liniparhomaloptera disparis, mild yet significant structuring is observed between populations living in Lantau Island and the New Territories (1%). High genetic diversity and population structuring are observed among populations of the rice fish Oryzias curvinotus, in which three genetically distinct groups (0.8 to 1%) are identified. The findings from this study have significant implications on the biodiversity conservation management of the local freshwater ecosystem.