Search efforts are underway to save an injured finless porpoise, an endangered mammal similar to the dolphin, in the Poyang Lake, China's largest freshwater lake.

On Tuesday, hydrobiology experts from the Chinese Academy of Sciences joined the search team consisting of volunteers and fisheries staff of east China's Jiangxi Province.

Through long-focus lens, several volunteers discovered a large fishhook on the back of the porpoise, but it disappeared before they could help.

"We're very worried. If the wound festers, the finless porpoise may die," said volunteer Yu Huigong.

Jiangxi Provincial Fishery Department sent the picture of the porpoise to its nine subdivisions, asking them to strengthen monitoring.

"Three days have passed, but we failed to find it. Our search will continue," said Zhan Shupin, a department employee.

Rarer than China's giant panda, the finless porpoise now teeters on the brink of extinction with a population of around 1,000. About 450 live in the Poyang Lake. (Xinhua)