China-Japan team examines Yangtze River porpoise.

BEIJING, July 26 Kyodo

A joint Sino-Japanese scientific research team is checking a portion of the Yangtze River for key information on the behavior of an endangered subspecies of finless porpoise, Chinese state media said Tuesday.

Biologists with the Chinese Academy of Sciences and Tomonari Akamatsu, a Japanese acoustics expert on aquatic life, recently began monitoring the migratory patterns of the Yangtze cowfish at a section of the river in Jiangxi Province, Xinhua News Agency reported.

Biologists do not know if the Yangtze cowfish migrates in rivers and lakes, but they believe migratory behavior data could help guide local governments on which areas of the river-lake system to protect.

The scientists saw 20 cowfish ''swimming and frolicking'' earlier this month, Xinhua said. Use of deep-water tracking and satellite positioning confirmed their migratory behavior and allowed collection of information about their habitat.

The freshwater porpoise, about 2,000 of which live in the Yangtze and adjoining Poyang and Dongting lakes, are declining by 7.3 percent annually because of water pollution and over-fishing, Xinhua said.

The freshwater mammal is under state protection.

Xinhua said about 63 percent of the Yangtze cowfish live in Poyang Lake and the Jiangxi section of the river, but a Jiangxi water quality official said he had never heard of any in the lake.

This current research is the third of its kind between Akamatsu and the Chinese academy since 1996.

A cowfish project upriver in the major city Wuhan was called off two years ago for lack of funds, according to the Greenpeace office in Beijing.

''For the cowfish, to do the research now is still useful,'' said Bai Yunwen, a Greenpeace campaigner who follows water quality issues.

Japanese aid also helped do a 2002 study of the baiji dolphin, another Yangtze River species listed as an endangered species.