A comprehensive survey of the diadromous animals of Lantau: assessment of distribution, population status, and conservation strategies

Flow-modification (e.g., damming) impacts the health of freshwater ecosystems by impeding animal movement and resource flow (i.e., ecological linkages). Diadromous animals are susceptible to disrupted linkages because they are obligate migrants that travel between river and sea ecosystems. Unfortunately, we know very little about Hong Kong's diadromous animals. We propose to evaluate the status, distribution, and ecology of diadromous species in Lantau. We also hope to also gain insights about the state of ecological linkages in Lantau's rivers, while testing mitigating measures.

First, we will conduct a wide-scale survey of diadromous animals in Lantau to map species distributions, which aids the identification of populations and rivers of conservation concern. Second, we will assess ecological linkages in representative Lantau rivers with a combined ‘isoscape’ and ‘landscape genomics’ approach using amino acid-specific Carbon-13 isotope and next-generation DNA sequencing data, respectively. Third, we will test the efficacy of structural enhancements for attenuating the impacts of dams/weirs on animal movement (e.g., fish ladders) using scaled-down ex-situ experiments.

Our work will inform policy and support the development of a possible remedy for disrupted river-sea linkages, helping to conserve diadromous animals in Lantau and the rivers they inhabit.