Crazy Crawdads on the Clark Fork River in Western Montana

Crawfish. Crawdads. Crayfish. Call em what you want, but check out these monsters in the Clark Fork River in Western Montana.

Carla McBride shared several photos on "The 406 !" Facebook page which you can find by clicking here. "Catching monster crawdads on the Clarkfork" is how Carla headlined the post.

My step dad called them crawdaddies, and I don't remember seeing ones that big on the banks of the Kankakee River back in Illinois. They certainly are much bigger than the crawfish boil we had down in Louisiana following a JRTC rotation with the Army.

Carla tells me she thinks the crawdads she caught were signal crayfish.

According to the Montana Field Guide, signal crayfish are abundant in the Lower Clark Fork and Kootenai Drainages, big harvests have been reported in the Noxon Reservior areas. They've also been spotted in the Missouri River drainages.

Here's more:

The signal crayfish, Pacifastacus leniusculus, is an large North American crayfish indigenous to the western United States. Members of this species are up to 15 cm in length. They are bluish-brown to reddish-brown in color with robust large smooth claws. They have a white to pale blue-green patch near the claw hinge (see photo). Like all crayfish, they are solitary and omnivorous, although their diet is mainly vegetarian they will eat anything from decaying roots and leaves to meat, including crayfish smaller than themselves.

The best way to fish a crawdad pattern in moving water is under an indicator. That allows a good drift, and keeps the fly at the proper depth. Crawdads vary in color from dark olive to brown, and in size as well. It pays to have a few different sizes of crawdads in your box, to mimic the most prevalent size. We’ve found a smaller imitation is more effective than a 6” fly, simply because there are many more smaller crawdads than larger. Additionally, you have a larger trout population to work with if you use a smaller pattern.

These are signal crawfish, which are native to the Columbia River drainage. However, interestingly enough, not native to Montana. One of our researchers, Stacy Schmidt, recently discovered this fact. Signal crawfish get large and are popular with folks who like to catch and eat them. The size of the one pictured is not surprising. Crawfish in the Clark Fork are safe to eat and the “worms” or parasites mentioned in the comments are very natural and fall off during the cooking process. In recent years we’ve learned more about the problems non-native crawfish can cause our waterways and now transporting live crawfish in the western fishing district is prohibited.