XINING - China's largest inland salt lake contained around 80,000 tonnes of naked carp in 2017, 30 times the number in 2002, according to local authorities Wednesday.

"Qinghai Lake has seen a 14-percent annual growth of naked carp stock this year," said Wang Hai, head of the fishing bureau of northwest China's Qinghai Province.

Owing to over-fishing and environmental deterioration, the population of naked carp sharply declined in the 1960s and 1970s.

In order to protect the species and restore the Qinghai Lake environment, the province banned naked carp fishing at the lake in 2001, following a series of temporary prohibitions from the 1980s onward.

More than 94 million artificially-bred fry have been released into the lake since 2002 to preserve the rare species. There has also been a crackdown on the illegal fishing, selling and processing of the fish.

The naked carp is endemic to Qinghai Lake, which is classified as endangered and on the China Species Red List.

The fish are critical not only to the existence of local bird species, but to the whole ecological balance of the highland lake.