In the July 8 Fort Frances Times, Kelli Saunders shared some great information about rusty crayfish in the Lake of the Woods watershed. She explained that rusty crayfish are an invasive species that have been present in Lake of the Woods for upwards of 20 years. They are an aggressive species of crayfish that is omnivorous, eating almost anything they can find, including vegetation.
I have fished on Lake of the Woods since I was a kid and there has been significant loss of vegetation across the north end of the lake over all these years. Once plentiful cabbage beds that always held populations of bass, pike, musky and walleyes have been decimated across the north part of the lake. Vast fields of coontail, which stays bright green and healthy late into the season have disappeared as well, evidently because of these crayfish. These weeds are also important for providing cover for young fish of all species, helping their survival.
The coontail loss has been really noticeable because I believe that it was essential to the survival of largemouth bass on the lake. The west arm of the lake held an excellent population of largemouths and they have all but disappeared in recent years. We fished the west arm of the lake in the Kenora Bass International for years and even won the tournament a couple of times, primarily catching largemouths around these weeds. Today, none of those spots have the weeds anymore and we simply don’t catch fish on any of them.
There are still some weeds out there but mostly in soft bottom bays that don’t provide the best fish habitat. It used to be that this stuff grew around rocks, which provided great habitat and attracted prey for these predator fish. I think that these rocky areas are more attractive to the crayfish so they are the places where they mow down all of the weeds. As an angler, it is disappointing for sure.
I mention this now because this year the loss of vegetation has been more noticeable than ever. There were patches of cabbage weeds that I have fished for the past 20 years on Shoal Lake (which is connected to the west arm of Lake of the Woods) that are gone this year, just like we have seen across Lake of the Woods. These were beautiful patches that always held schools of smallmouths throughout the summer. Other areas on Lake of the Woods that I have fished for many years and still had some weeds are completely void.
While these crayfish have had an impact on the lake, it’s not all bad. Their numbers are incredibly high and it appears most fish in the lake have quite an appetite for them. I have seen the stomachs of perch, walleye and even burbot in the winter, absolutely full of these crayfish. Bass are constantly puking them up as you are fighting them, sometimes still fully intact. Most of these fish can adapt to whatever the best option is for food so they go where the crayfish are. Aside from the largemouths I don’t feel like the populations of the other species have been hurt, but the fish are showing up in different places.
If you fish the north and central sections of Lake of the Woods, the smallmouth numbers are incredible. The Kenora area has the best fishing on the lake in my opinion for numbers of fish and they are totally focused on eating crayfish. Use a crayfish imitating crankbait or soft plastic around areas with sand and boulders and you’ll run into bass. I’ve also been seeing walleyes remain in shallow water much later into the summer than we used to see and I think it’s because they are gorging on these crayfish.
I think these crayfish are present in Rainy Lake as well but I’m not certain because I haven’t seen the same reduction in vegetation out there that we’ve seen on Lake of the Woods. In case you didn’t know, it is illegal to transport crayfish in Northwest Ontario because we don’t want to see these invasive critters show up in more bodies of water than they are already found.