We have always had them and they come in cycles. Usually we have them bad for a year or two then we have 3 years of less. All depends on when they apply the lampreyacide and how high or low the water level is when the do it. That's my 2 cents at least. I know one year the water level was so high that the fish ladder wasn't a barrier at all. Many of them just blew on by and did there thing.
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