Chinese fisheries authorities have taken emergency measures to protect finless porpoises after the deaths of more than 20 of the endangered species were reported earlier this month.

Authorities in Dongting and Poyang lakes linked to the Yangtze River have launched campaigns to reduce human impact on the lives of the porpoises, which are native to, and only found in, the Yangtze River Basin.

Since the beginning of this year, more than 20 finless porpoises have been found dead in the Yangtze River and the two lakes. Initial autopsies showed that most of them died of starvation, and experts warned that human activities, such as shipping, sand gathering, illegal fishing and water pollution are all possible causes for their deaths.

On the Poyang Lake in east Jiangxi province, a six-month campaign was initiated in late April by the Ministry of Agriculture and local fisheries authorities to crack down on illegal fishing that could lead to a shortage of food for porpoises.

The Poyang Lake, with 300 to 500 finless porpoises, or one-third of the country's total, has reported the deaths of six porpoises this year.

On the eastern part of Dongting Lake, which has seen the deaths of 10 porpoises this year, authorities have decided to suspend all sand gathering activities for two months and they have kept a close eye on illegal fishing and pollution discharge.

The fishery bureau of the city of Yueyang, which administers the Dongting Lake, has dispatched eight vessels to patrol the lake day and night.

The booming sand gathering industry has deprived many fish of proper?habitats to reproduce and has, therefore, threatened the porpoises' food sources, said Yu Daoping, an expert who has been studying porpoises for nearly 30 years.

Yu added that a drought plaguing the entire Yangtze River Basin last year also resulted in scarce fishery resources there.

Although several natural reserves were established in the river and two lakes to protect the endangered species, the measures can only delay the species' extinction, Yu said.

He pointed out that the only feasible way to save the porpoises is to help them to move from their current habitats that have been heavily influenced by human activities and conduct research on artificial propagation and breeding of the species.