It's a water quality issue that we have had for quite a long time--namely, all the effluents, mostly industrial effluents, that went into St. Marys. Many of them have accumulated in the sediments too. We used to have a paper mill; I think it's closed now.
Anyway, due to usual Ministry of the Environment regulations, as in trying to restrict any kind of toxic outflow from any kind of industrial entity, over time that has resulted in generally cleaning the water up. Don't get me wrong; it's a positive thing, and I very much applaud that. We should do more of it. But the issue is that sea lamprey actually need good quality water, clean water, cold water for spawning, just like salmon and trout do. An unwanted effect of the cleanup of the river itself, namely cutting down on toxic load and what not and improvement of water quality, has resulted in sea lamprey being able to move into it and spawn, and, more importantly, the larvae being able to survive in the sediments.
Just before coming here I read a report written by Lupi and Hoehn that was published in 1998 and reported that the Great Lakes Fishery Commission had looked at the number of sea lamprey coming out of St. Marys and seeding northern Lake Huron in 1998, which was 14 years ago. The average estimated number of sea lamprey per lake was about 50,000. However, in northern Lake Huron--and remember that all the lampreys are coming from St. Marys as a point of origin--their number was estimated at 400,000, more than all the Great Lakes combined.
I assume the next issue would be if we can do streams, why can we not do St. Marys? The reason it's so difficult to control is that St. Marys is a very large river. It is very deep and very fast. Putting a chemical into a very deep and very fast river is not particularly effective, even when using a huge amount, because the flow takes it away very quickly. We can control through chemical only in some backwaters kind of sporadically. It doesn't really make a dent.
That river has enjoyed a lot of research attention in terms of the dams in Sault Ste. Marie. The Brookfield dam and the Edison company on the other side have several traps built into the dams. Those traps are catching sea lamprey every year. There's a lot of research attention coming from the University of Guelph as well as from me and DFO locally to try to figure out how we can increase the efficiency of those traps as much as possible, given that chemical control wouldn't work.
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