The largest-known population of Indo-Pacific humpback dolphins (Sousa
chinensis), consisting of approximately 2,000 individuals, occurs in the estuary
of the Pearl River (China’s second largest river), and uses waters of Guangdong
Province, Macao, and Hong Kong as parts of its range. It has been intensively
studied in Hong Kong since the early 1990s, and in that area has shown a
sustained decline for more than a decade. The main threat appears to be loss
and degradation of habitat due to large-scale engineering projects, but other
threats (e.g., vessel collision, fisheries by-catch, pollution) also exist, and some
evidence suggests that the overall population is nearing a critical point for
population recovery. Recent impact assessment work in Hong Kong using
vessel-based, land-based, and acoustic surveys is presented here and we attempt
to put the Hong Kong situation into the context of the wider Pearl River
population. Despite the large body of work that has been done on these animals
in the past three decades, there are still many unanswered questions. Now is the
right time to take appropriate action to protect critical habitat and conduct
focused work to halt the decline, and promote population recovery, thereby
increasing the prospects for long-term survival. Because the Pearl River Estuary
population is still relatively large and apparently viable, the chances for success
appear promising. We conclude with a series of recommendations for wildlife
management authorities.