Thank you.
Speaking specifically to your question, we have a target of about 4,000 lampreys in Lake Erie, a relatively smaller system than those of the other Great Lakes. We were within that target for a large number of years. Then lamprey populations started to increase within Lake Erie.
It was really kind of tragic, because, as you know, the Great Lakes states and the Province of Ontario had spent decades trying to re-establish lake trout into those systems. We got to the point where we had the mean age of females up at around seven. The female lake trout were just at the point where they were going to start to naturally reproduce when the lamprey populations increased and knocked the mean age of the females down to about five, to a point where we weren't having much natural reproduction.
The commission decided that, as there were only 10 tributaries in Lake Erie that we knew had spawning populations of sea lamprey in them, we would go in and we would treat every stream in Lake Erie in two consecutive years. We treated in the spring one year, and then in the next year we treated in the fall.
Our expectation at that time was that we would knock the stuffing out of the sea lamprey populations in Lake Erie. We thought that spawner abundance would be very low and there'd be very little recruitment. We actually believed that we would drive sea lamprey populations down to a level where they didn't colonize some of the other streams.
Well, what happened was that the lamprey populations were increasing, and we went in and we treated it two years in a row. The population—the target is 4,000—went to 40,000 sea lampreys in Lake Erie. So we'd put forward our maximum level of control effort and had the highest populations we'd ever seen in Lake Erie.
We went back to the streams that we treated and we were correct: there were virtually no spawning lampreys in the system. We had effectively controlled them in the tributaries to Lake Erie.
As Commissioner Lambe pointed out, we went to the Huron-Erie corridor to see what was happening. We've been doing a lot of work—last year, and ongoing this spring—looking for populations of larval lamprey. We have found lamprey. By doing extensive trawling last fall, we were able to find lamprey transformers migrating down the Detroit River into Lake Erie.
What we think has happened is that through water quality improvements in that system, that area has now become a successful reproductive area for spawning sea lampreys. So we are going out trying to find exactly where they're spawning in the Huron-Erie corridor this spring.
This is not new. We had exactly the same thing happen.... We had Lake Huron under relatively good control, and suddenly it went absolutely crazy. That was because of tremendous water quality improvements and the construction of some wonderful habitat in the riffles in the St. Mary's River. What we produced was the finest sea lamprey spawning area in the Great Lakes. The St. Mary's River suddenly was producing more lampreys than all the rest of the Great Lakes combined.
What ended up happening was that through research we found an effective way to, (a), find them, and then, (b), when we developed a new lampricide, granular Bayluscide, we were able to use that to control them. We've been able to knock the abundance of lampreys in the St. Mary's River from 5.8 million down to about 0.6 million.