Because it is rare. According to a data from the Freshwater Fisheries Research Center of Chinese Academy of Fishery Sciences, the output of river knives along the Yangtze River was 3,750 tons in 1973 and about 370 tons in 1983. In 2002, the output was less than100t. Now, especially this year, the output of saury is even lower. Fishermen can only catch two small fish for half a day, and if they are unlucky, they can't even catch the fishy smell. Yangzhou, where the author lives, is famous for swordfish in history, but from the beginning of this year to now, fishermen still haven't caught enough fish. Even if some people can still have fun, 10 years later, people may only have fun in museums.

There are two main reasons for the scarcity of swordfish in the Yangtze River year by year, one is overfishing, and the other is the deterioration of water environment quality. Now the country has restricted fishing, but the improvement of water environment quality is not optimistic. The water environment not only affects swordfish, but also the "Yangtze River Poisonous Fish" incident that happened last year.

Coilia ectenes, also known as Coilia ectenes and Coilia ectenes, is a migratory fish, which is called "Four Fresh Species of the Yangtze River" together with Carp, Mudhead and Bighead Carp. Usually living in the sea, from February to March every year, bonito with long jaws enters the river from the sea and migrates upstream for reproduction. Spawning groups enter lakes and tributaries along the Yangtze River or lay eggs in the main stream of the Yangtze River. Due to the increasing pollution and overfishing in the Yangtze River, the output of swordfish has been declining year by year. Swordfish is slender, with a thin side, much like a sharp knife. It is silvery white and tender, but it has many hairy thorns. Meat tastes delicious, fat but not greasy, and has a faint fragrance. After Tomb-Sweeping Day, swordfish became old, commonly known as Lao Dao.

The content of crude protein and ash in fresh muscle samples of wild saury was significantly lower than that of cultured saury (P < 0.05), while the content of crude fat was significantly higher than that of cultured saury (P

Tryptophan is the first restrictive amino acid in wild animals and cultured animals, and the essential amino acid index (EAAI) of cultured animals is significantly higher than that of wild animals (P

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Why is Yangtze saury so expensive? Other fish nutrition is not bad _ People's Network