Ecological impacts of the third-runway system of the Hong Kong International Airport on Chinese white dolphins (Sousa chinensis)

Abstract

Indo-Pacific humpback dolphin (Sousa chinensis), or locally known as Chinese White Dolphin, is one of the resident cetacean species of conservation concern in Hong Kong waters. Over the years, the abundance of Chinese White Dolphins in Hong Kong waters has been found decreasing primarily due to habitat loss from coastal reclamation projects and other human disturbances such as underwater noise generated by heavy marine traffic and lethal injury arising from high-speed ferries.

Recently, the proposed Third-runway System of the Hong Kong International Airport has been much criticized for its threats to Chinese White Dolphins. The environmental impact assessment (EIA) of this project has been approved by the Director of Environmental Protection and the environmental permits are issued. However, many local dolphin experts and ecologists consider the EIA report poor in quality and the proposed mitigation measures insufficient in compensating the impacts of the project on Chinese White Dolphins. This study was set out to evaluate the Third-runway System EIA report.

A literature review was first conducted to categorize the different types of anthropogenic impacts on Chinese White Dolphins and the natural factors affecting its population were also investigated. Secondly, the EIA report of the Third-runway System was cross-checked with the study brief, the EIA Ordinance and its Technical Memorandum (TM) to evaluate compliances with relevant requirements. After reviewing the documents, about 15 items in the ecological impact assessment of the EIA report failed to meet the requirements of both the study brief and TM. Thirdly, some key issues about the ecological impact assessment and mitigation measures with respect to Chinese White Dolphins were selected for an in-depth analysis. The views and comments of local experts on the ecological impact assessment on the Chinese White Dolphins were collected by emails and face-to-face interviews. Night-time activities of the dolphins, cumulative impacts, the effectiveness of the proposed Marine Park, SkyPier high speed ferries’ speed restrictions and enhancement measures are their key concerns in the proposed project.

Case studies from overseas with mitigation measures such as vessel speed restriction, cetacean detection system within the shipping channels and marine protected areas, and the designation of acoustic buffer zones for cetaceans were reviewed. The feasibility of such mitigation measures for enhancing the environmental monitoring and audit programme, and strategic environmental assessment of the proposed Third-runway System was made finally.