Changing Great Lakes Fisheries

I’m not screaming FIRE! right now and don’t think this is any more cause for concern than about a dozen other things happening in the basin, but Lake Huron’s salmon population crashed quickly and now Lake Michigan’s salmon fishery is making the national news.

King salmon are struggling to hold on in Lake Huron, but lake trout and walleye populations are recovering there. While lake trout were once the top predator in Lake Michigan, there probably aren’t any wild fish left here despite massive stocking efforts and spawning habitat protection. We mentioned in early March that lake trout stocking in Lake Michigan will increase 25% to 3.5 million fish in 2011, and lake trout fishing has been closed for a while around important breeding habitat in the Beaver Island archipelago for example, but the problem isn’t habitat or stocking or fishing pressure. It’s those damn alewives.

Salmon were originally introduced to the Great Lakes to control alewife populations, another introduced species. Alewives have a thiamine deficiency compared to native forage fish that prevents lake trout from spawning when they feed on them.

Now there are still plenty of big lake trout to be caught in Lake Michigan, they just aren’t wild. And there are still a lot of king salmon in Lake Michigan as well, but charter captains reported decreased catch rates this past fall. We happened to have what by all accounts was a very strong and long run of salmon in the Pere Marquette this past year, it was just late because of the warm fall. The NPR story didn’t report any data from the state’s scientific studies of salmon numbers so all of the talk is anecdotal. Low charter boat catch rates this past fall may have been a fluke, but an alewife-salmon crash happened in Lake Huron, so it seems like it could happen here as well.

Lake Michigan’s fishery is certainly a complicated, tangled mess. Luckily for us, we’re pretty happy to fish for lake trout, steelhead, carp, salmon, whatever. Lake Michigan is an amazing body of water that turns out trophy fish of whatever species. So bring on the changes (but not asian carp). We’ll tie new flies.