Chinese white dolphin
The Agriculture, Fisheries and Conservation Department released the marine mammal monitoring report for 2022-23. During the research period from April last year to March this year, researchers found 181 pods of Chinese white dolphins in 10 survey areas across Hong Kong, with a total of 646 individuals, an increase year-on-year. 16.6%; 55 groups of finless porpoises were also found during the period, with a total of 121 individuals, a year-on-year decrease of 23.4%. The study also found that the encounter rates of Chinese white dolphins per 100 square kilometers in Northeast Lantau and Northwest Lantau dropped further to 0 and 0.3 respectively last year. The report describes the Chinese white dolphin as “almost extinct in the entire waters of North Lantau” and estimates that there are only 34 Chinese white dolphins in the four survey areas on Lantau.
The 2022-23 marine mammal monitoring report is funded by the Agriculture, Fisheries and Conservation Department. During the 12-month research period from April last year to March this year, the researchers sailed 6,136 kilometers in 10 survey areas in Hong Kong, conducted 198 transect boat surveys, and observed 181 groups of Chinese white dolphins, with a total of 646 individuals. A total of 554 individuals were observed in the previous year, an increase of 16.6%; 55 groups of finless porpoises were found, with a total of 121 individuals, a decrease of 23.4% compared to the 158 individuals in the previous year.
The report points out that the main habitats of Chinese white dolphins in 2022 are concentrated in the coastal waters of West Lantau Island and the western end of Southwest Lantau Island, in the area between Tai O Peninsula and Diversion Peninsula; the overall estimation of the four survey areas in the southwest, west, northwest and northeast of Lantau Island is There are 34 birds, while the numbers in the past five years (2017 to 21) were 47, 32, 52, 37 and 40 respectively.
Chinese white dolphin
The report points out that the usage rate of dolphins in the waters of North Lantau has dropped significantly in the past 10 years. Since 2016, they have only been concentrated in the western end of this waters. In the past four years, they have been restricted to Shacha and Lung Kwu Chau Marine Park. With the large-scale Reclamation and offshore development projects have been implemented one after another, and its usage has not shown any obvious signs of recovery. The usage of dolphins in the Tai Mo To Marine Park, Sha Chau and Lung Kwu Chau Marine Parks in the waters of North Lantau has continued to decrease significantly, while the Southwest Lantau Marine Park has still recorded a stable and continued high usage of dolphins. Referring to the data on the encounter rate of Chinese white dolphins per 100 square kilometers in the report, the occurrence of Chinese white dolphins in different waters of Lantau Island has greatly decreased in the past 10 years, and the encounter rate of Northeast Lantau in 2022/23 has recorded 0 encounter rate for 7 consecutive years; As for North West Lantau (0.3), West Lantau (14) and South West Lantau (2.5), they decreased by 0.1 to 0.5 respectively from the previous year.
As for finless porpoise, the finless porpoise habitats with the highest usage in 2022 are only concentrated in the offshore waters of Southwest Lantau Island, especially in the area east and south of Soko Islands. From 2015 to 2017, the usage of finless porpoises was continuously high in the waters between Shek Kwu Chau and So Ko Ko Islands, and then decreased significantly in the following five years. In Shek Kwu Chau adjacent to the “Integrated Waste Management Facility” development project In water areas, the downward trend is particularly obvious.
The original article was published on AM730
2023-10-09 23:15:27
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