Wising up to whirling disease

  Scientists are considering new management strategies for whirling disease, which has been attacking fish in the West since the early 1990s. The disease has spread from one Western river to the next, eluding attempts at a cure and draining funds from state game and fish department budgets. Trout get the disease by eating worms infected by the microscopic parasite Tubifex tubifex, which inhabits polluted waters. As the parasite feeds on fish cartilage and nerve cells, trout chase their tails - or "whirl' - while feeding. Young populations of trout are most susceptible. Although it was believed that once established in the wild, the parasite could not be eliminated, new research has scientists hopeful that's not the case. "We don't have a silver bullet to make it all go away, but we're starting to have research that gives us a road map for dealing with the disease," says David Nickum, conservation director of Trout Unlimited in Boulder, Colo.

Trout Unlimited researchers say the parasite thrives in polluted rivers and in warmer summer temperatures. Now, scientists hope to get trout to spawn earlier in the year, before fish are at the greatest risk of infection.

For a free copy of the 36-page Whirling Disease in the U.S., write Trout Unlimited, 1500 Wilson Blvd., Suite 310, Arlington, VA 22209-2404, or download the report from www.tu.org/library/conservation.html.

* Rebecca Clarren
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