Taiwan has reported to the World Organisation for Animal Health (OIE) information on a redclaw crayfish plague after massive die-offs of the crustaceans in several counties, the Bureau of Animal and Plant Health Inspection and Quarantine said.
The bureau said that in Taiwan, redclaw crayfish were in the past kept as decorative aquarium additions and were not included in inspection and quarantine lists. However, after the latest plague, the bureau has decided to revise the regulations to include the crayfish.
The species was previously only allowed to be imported for research purposes and has never been approved for import or export, the Fisheries Agency said.
Despite this, the bureau said that people in four counties — Miaoli, Changhua, Pingtung and Yunlin — have been discovered raising redclaw crayfish illegally.
Five ponds in Miaoli, Changhua and Pingtung were found to be infected with the plague last month, with a 40 percent mortality rate, representing 224,000 individual shellfish.
The bureau was later able to confirm the plague and notified the OIE on Tuesday last week.
Bureau Deputy Director-General Chao Pan-hua (趙磐華) said all the dead redclaw crayfish were destroyed on Jan. 28 and that there is no question of any of them having made their way to market.
Cheng Shih-chin of Fish World Magazine said the species was introduced about two decades ago as a decorative aquarium addition, but did not prove very popular.
However, over the past three or four years, people have turned to redclaw crayfish as an alternative to giant river prawns after the latter were found to be prone to disease.
Pond-raised redclaw crayfish sell for up to NT$400 (US$13) per catty (600g), while white shrimp sell for between NT$180 and NT$200, and giant tiger prawns for NT$300.