Crayfish (Procambarus clarkii), which originated from the Mississippi River region in the United States, found their way to China through Japan in early 20th century. Biologically, crayfish are more homologous with crab than they are with shrimp. But in China, crayfish are called "Xiao Long Xia", which literally means "small dragon shrimp". The Chinese counterpart of the name lobster is "Long Xia" which literally means "dragon shrimp". Therefore, in Chinese, crayfish, lobster and white-leg shrimp fall into the shrimp category. With their similar appearance and similar market price, Chinese consumers think crayfish and shrimp are of the same species.
Challenged by disease outbreaks, China's production of Litopenaeus vannamei decreased rapidly from 1.5 million tons to 0.7-0.8 million tons, according to data released from the industry. And the prices of Litopenaeus vannamei remain very low because of imports and smuggling. However, the challenges along with the unsatisfactory amount of meat from crayfish and the trouble involved in the preparation of it do not prevent the crayfish from becoming the "new king" of aquatic crustacean in China.
The production of crayfish climbed from 0.6 million tons (year 2013), 0.72 million tons (2015), 0.85 million tons (2016), to 1.1 million tons in 2017. And the production of crayfish has been increasing faster - more than 10% in the past two years, replacing shrimp as the number one aqua crustacean product with no near rival. For people who frequently eat out for supper, the crayfish is a popular dish on the menu, and even those who have never tried crayfish are aware of its popularity. According to some experts, the consumer demand for crayfish is more than two million tons, which means the consumption gap is approximately 0.8 million tons per year.
In China, there are more than one million hectares of aquaculture farms, of which 80% are of the rice-cum-fish culture type. But there are less than 0.5 million tons of crayfish feed supplied per year. The supply of crayfish feed is insufficient for the rice-cum-fish culture model. With the rapid increase of demand, some technical challenges also rise. Besides, there is still a high-value potential market for functional feed to enhance immunity. The "crayfish plague" in May hits China's aqua farms every year. It is still unknown what causes this plague. Some experts point out that the pathogen is WSSV; other experts, however, think it is triggered by vibrio; and some people think it is bad water environments, where remnants and feces of living organisms or rotten water plants cause the disease. Others hold that it is caused by enteritis.
Kemin AquaScienceTM is conducting some trials to fight "crayfish plague". The trials are arranged in Hubei, Sichuan, and others. Some products— BactotreetTM, Aleta®, Lysoforte®, OrsentialTM and ColostaTM, for example— will be tested on crayfish.