Quote:
Originally Posted by TroutBaus
I believe that whirling has been in the southern alberta rivers for some time, however the colder more northern watersheds can kill it. Just something were all goimg to have to live with...
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I agree with your statement that the parasite has been in our rivers for some time. Our long history with anglers migrating back and forth from Montana, Colorado and Wyoming and the fish hatchery/trade, it was inevitable that we would see the disease in Alberta one day.
I think the timing of the discovery of whirling disease in Alberta is tied to somewhat lower spring runoff events the past couple of years. Theory is that low runoff years allows more sediment to accumulate in streams and rivers providing increased habitat for the intermediate worm (
Tubifex tubifex) host of the parasite (
Myxobolus cerebralis). With more
Tubifex worms in the river systems there is greater potential for propagation of the parasite and then greater chance of fish infection. High spring runoff water flows not only washes out the fine sediment, but also the worms and the parasite spores that could lie dormant till favorable summer water conditions return. With all of our late season snowfall hopefully we will have normal spring runoff sufficient to washout fine sediment and reduce the risk of fish infection in these high gradient headwaters.