Distribution

Chinese White Dolphin (Sousa chinensis) is part of a broader family of Indo-Pacific humpback dolphins, which inhabit coastal waters throughout the Indian and western Pacific Oceans. The distribution of the species extends from central China, near the mouth of the Yangtze River, southward through the waters of Southeast Asia, reaching as far southeast as Borneo and as far west as the Orissa coast of India. Along the coast of China, there are approximately 7 to 8 populations of Chinese White Dolphins.

Hong Kong waters represents a small portion of the eastern-most part of the home range of the CWD population in the Pearl River Estuary near Lingdingyang with an estimated population of around 1,100 individuals. The total number of CWDs in the entire Pearl River Estuary exceeds 2,000, making it one of the largest populations of this species in the world. These dolphins exhibit a strong preference for estuarine waters and are commonly found throughout the Pearl River Estuary, including the western waters of Hong Kong, particularly in the west and south Lantau areas.

(Only Chinese Version Available)

Ways to estimate Chinese White Dolphins

The line transect boat survey is a method used to assess dolphin populations by conducting surveys along fixed routes, known as transects, in various areas. During these surveys, two researchers are tasked with observing dolphins while simultaneously recording the time, positions, and other environmental conditions. They document essential information such as group size, the distance between the boat and the dolphins, and the angle from the bow. The data collected is then entered into a specialized computer program called DISTANCE, which estimates the density and abundance of dolphins in the surveyed area.

Line Transect Boat Survey

In terms of the Pearl River Estuary CWD distribution and abundance in Hong Kong waters, it can be referred to the reports on Monitoring of Marine Mammals in Hong Kong as below.

Monitoring of Marine Mammals in Hong Kong Waters (2024-25)

Monitoring of Marine Mammals in Hong Kong Waters (2023-24)

Monitoring of Marine Mammals in Hong Kong Waters (2022-23)

Our department provides the recent three years of the relevant reports for viewing/downloading. To view previous reports, please visit Further Reference. For further enquiry, please contact us via ftomcw@afcd.gov.hk or by calling 1823.

Another method used in dolphin research is photo-identification. This involves taking photographs of unique features on a dolphin's back and dorsal fin, such as nicks, scars, and distinctive color patterns. Each dolphin is identified based on these characteristics, which can provide valuable information about individual home ranges and overall population.

Regarding photo-identification efforts, more than 1,100 dolphins have been identified in Hong Kong and the Pearl River Estuary. New dolphins continue to be added to the photo-identification catalog, enhancing our understanding of the home-ranges of these dolphins and the population dynamics.

Videos of Chinese White Dolphin

dolphin.mov (4.02Mb)
Video showing a group of Chinese White Dolphins swimming in the sea.

dolphin2.mov (6.42Mb)
Video showing a group of Chinese White Dolphins swimming in the sea.

dolphin3.mov (4.66Mb)
Video showing a group of Chinese White Dolphins swimming in the sea.