Re ECF Project: ECF 2015-72

Project Title: Coral restoration in Tolo Harbour and Channel

Applicant: Dr Put Ang, Jr, School of Life Sciences, The Chinese University of Hong Kong

Total Approved Grant: $499,920

Duration: 15/3/2016 to 14/9/2017

Project Status/Remarks: Completed

Coral communities in Tolo Harbour and Channel were destroyed and recovery was slow. A pilot scale restoration study using coral transportation technique was carried out in 2013-15 and the results were promising. This project will utilize similar techniques developed to apply to more sites within Tolo Harbour and Channel as well as at a larger scale, so as to facilitate the restoration of coral communities in the area.

Summary of the Findings/Outcomes:
Coral communities in Tolo Harbour and Channel (THAC), northeastern Hong Kong, were completely degraded in 1980s due to pollution. Although pollution abatement project was installed in 1998 with significant improvement in water quality, no significant coral recovery was recorded thereafter. Natural coral recovery was unlikely so artificial restoration project needed to be undertaken to facilitate coral recovery. The project team examined the use of coral fragments to kick start coral recovery. Due to limited number of “coral of opportunities” available, far lower than that available in earlier years, only transplants from two species, the massive Platygyra acuta and the foliose Lithophyllon undulatum were used. The coral transplants all survived well for 11 months within the project period in 2016-2017 in the three transplant sites: Bush Reef, Knob Reef and Chek Chau, the latter being outside the main THAC. Transplants of the massive Platygyra acuta had 100% survivorship although slower or negative growth rate could occasionally be recorded due to sea urchin predation. Likewise, those of the foliose Lithophyllon undulatum also exhibited a near 100% survival with less predation impact. The high survivorship of these coral transplants and the overall net tissue growth indicated that corals could actually grow well in all these degraded sites, thus were suitable candidates for coral restoration project. Artificial coral transplantation thus appears to be an effective, if not the only feasible strategy to restore these degraded communities in the absence of recovery from natural recruitment. The research team has prepared two manuscripts with follow up data on repair of degraded coral colonies using coral transplants.