“Although the parasite has been confirmed in fish samples from Lees Ferry, to date no trout have displayed any disease symptoms such as the classic whirling motion,” said Fisheries Chief Kirk Young. “In fact, just the opposite is true; the Ferry is currently providing some of its best fishing in more than a decade.”

Young emphasized that there are no human health implications for this fish parasite.

Whirling disease is caused by a microscopic parasite that damages cartilage and compromises the nervous system of trout and other salmonids, but no other fish species. The disease takes its name because it can cause fish to swim in an uncontrolled whirling motion.

This is the second detection of the whirling disease parasite in trout at the Ferry; the first was in 2007. While the parasite was detected in 2007, it did not become established in the trout population and until now was absent from annual samples taken since then.

“It’s pretty clear from the recent tests that this parasite is back again in the trout population at the Ferry,” Young said. “What we don’t know is how the parasite got to the Ferry, nor do we know how it may manifest itself.”

There have been no fish die offs detected due to the whirling disease parasite at Lees Ferry. “Its presence can, but does not always cause significant trout population losses and typically affects young or immature trout the most,” Young advised.

The whirling disease parasite is found at hundreds of waters in 25 states across the nation, including Colorado, New Mexico and Nevada. “We have been very fortunate in Arizona – we don’t have this parasite showing up anywhere else in Arizona. We want to keep it that way,” Young said.

It’s critical to have the conscientious cooperation of boaters, anglers and other recreational users along this stretch of the Colorado River and at other waters as well.

“The life cycle of this parasite, which involves both trout and tubifex worms along with microscopic spores, results in this parasite being readily transportable unless anglers and boaters are conscientious about cleaning and decontaminating their equipment,” Young said.

Anglers and boaters are asked to:

* Never transport live fish from one body of water to another – anywhere, not just from the Ferry;

* Do not dispose of fish heads, skeletons or entrails in any body of water, this can spread the disease-causing parasites;

* Do not discard entrails or heads of fish down a garbage disposal. The whirling disease parasite can survive most water treatment plants and infect areas downstream;

* Carefully clean mud and vegetation from all equipment, such as boats, trailers, waders, boots, float tubes and fins. Rinse all mud and debris from equipment and wading gear, and drain water from boats before leaving the area where you’ve been fishing;

* Drain and dry boat bilges, live wells, and lower units.

BEFORE using waders, wading shoes, or fishing gear at another waterway, clean equipment with one of the following:

* Saturate waders and other gear with full-strength "Commercial Solutions Formula 409® Cleaner Degreaser Disinfectant" or "Formula 409® All Purpose Cleaner Antibacterial Kitchen Lemon Fresh" or other cleaners, that contain at least 0.3 percent of the quaternary ammonium compound alkyl dimethyl benzyl ammonium chloride for at least 10 minutes or,

* Dip, wipe, or spray waders and other gear with 50-percent bleach solution (one part household chlorine bleach to one part water) or,

* Soak waders and other gear for 10 minutes in a 10-percent bleach solution (one part household chlorine bleach to nine parts water) or,

* Pour boiling water (at least 200°F) over your gear and allow to cool.

“The spores of the whirling disease parasite are known to adhere to these kinds of materials and can potentially be carried on gear from one water to another,” Young advised.

Young added that there are also other reasons to clean and decontaminate equipment and boats.

“We have a long list of potential invasive species from New Zealand mudsnails, rock snot, to invasive mussels that can be spread from one body of water to another if simple precautions are not taken. Please make it a habit to Clean, Drain, and Dry, and don’t give any of these invaders a free ride to a new water.”

News Source: Arizona F&G - May. 31, 2012