Threat of extinction

"Large-scale fishing and water pollution threatens the species, and that has led to the extravagant prices," Dai says.

"But there are thousands of delicious fish out there. I don't think you have to crave for a single type that is on the verge of extinction."

Knife fish is reputed to be one of the three most delicious kinds of fish in the Yangtze, the other two being reeves shad and blowfish. Their numbers, too, have greatly declined in recent years because of over-fishing and pollution, Dai says.

"Most of the reeves shad and blowfish are artificially cultured now, which has greatly affected the flavor. If the massive fishing continues, knife fish will face the same fate."

As a migratory species, knife fish migrate from the sea to the Yangtze River in the breeding season in spring each year and spawn in the middle reaches of the river. Then the baby fish swim down the river to the sea, where they become adults.

But many fishers set up their nets on the migration path and catch the fish before they arrive at the middle reaches to spawn.

Regulations that restrict when and where the knife fish can be caught have been in force for the past 10 years, but because of the huge demands these limits appear to have done little to deter fishers.

Zheng Jinliang, an expert on aquatic products in Jiangsu province, told the Shanghai-based Xinmin Evening News that fishing of the species needed to be banned in the Yangtze to save it from extinction.

"If that were done, the number of the fish would increase significantly in five or six years, which would ultimately benefit both the fishers and the diners. For some diners, the extinction of the fish only means the lack of a kind of delicious food. But for the Yangtze River, it would lose a precious species."

yangyijun@chinadaily.com.cn