October 19, 2006

Whirling disease cripples trout business in the US state of Utah

Whirling disease has made a huge dent in the sales of trout and trout products in the US state of Utah, causing sales to drop from US$1.9 million in 1998 to US$560,000 last year, according to an aquaculture census released Tuesday (Oct 19). 

Private hatchery owners are lobbying to force the Utah Department of Agriculture and Food to conduct more than one test for the disease before closing down aquaculture operations.

The census shows that there were only 11 aquaculture operations in the state reporting sales during 2005, almost half of that in 1998. Food-sized trout accounted for US$463,000 in sales during 2005 - accounting for 83 percent of all aquaculture sales in the state. Private hatcheries, are no longer a factor in the aquaculture industry, according to the aquaculture census.

Whirling disease afflicts juvenile fish (fingerlings and fry) of salmon and trout species and causes skeletal deformation and neurological damage. Fish "whirl" rather than swim forward and find feeding difficult. The mortality rate is high for fingerlings, up to 90 percent of infected populations, and those that do survive are deformed by the parasites in their cartilage and bone.

US aquaculture production is a billion-dollar industry which has grown by 11.7 percent over the past seven years.