Colossal Catfish Cause Conservation Complications

Contributor: Tyler McKee, MD Department of Natural Resources

We may be under a stay-at-home order, but the natural world is on the move as spring comes into full swing. Unfortunately, that includes invasive species. One invasive threat, that has been on the move in Chesapeake watershed since the 1960s, is invasive catfish. Sightings and catch of these fish pick up each spring as more anglers start hitting the water. As fishing season kicks into gear, we picked blue and flathead catfish as the April Invaders of the Month.

Colossal Catfish Cause Conservation Complications
84 lb blue catfish caught in the Potomac River near Fort Washington, MD DNR Fisheries Service.

Both flathead and particularly blue catfish are considered good recreational fish. They offer some challenge when catching and good eating. That’s why these invasive catfish were introduced to the James and Rappohanok rivers in the 1960s. Both species are native to the central US in the Mississippi, Ohio and Missouri river systems. From the initial introduction in the James and Rappohanok, the blue catfish has spread to the Potomac and eventually to every major tributary of the Chesapeake Bay. Flathead has spread less, but can still be found in the Potomack, Elk, and Sassafrass rivers. 

Predation is the main threat of invasive catfish to our native species and ecosystems. While most of the catfish diet consists of vegetation, it does prey on important and imperilled animals in the bay. Menhaden, American shad and other fish make up small portions of the blue catfish’s diet. In areas with higher salinity, blue crabs can make up a significant portion of their diet. Despite the fact that predation is not heavy on many natives, any amount can be detrimental to commercial fisheries, recreation, and restoration efforts.

Colossal Catfish Cause Conservation Complications
Flathead Catfish Todd Mathes, Department of Natural Resources, 

Both invasive species can be distinguished from our native species with relative ease. The blue catfish has smooth blue-slate skin and can grow quite large. The record size catch of blue in Maryland is 84 pounds, versus the record 9.6 pound native white catfish. Flathead catfish, though not as large as blue catfish, is also significantly larger than native catfish. Flatheads generally look more similar to yellow and brown bullheads than white catfish. However, flatheads have a projected lower jaw unlike the bullheads.

When we are able to head out again, all of us anglers can do our part to help control these invasive catfish. Catch them! The Maryland Department of Natural Resources asks anglers to remove and kill any blue and flathead catfish they catch. Catch and release of these fish is discouraged, as they are invasive predators and pose a serious long-term threat to our native species. It is also illegal to transport live blue and flathead catfish into another body of water. If you don’t fish, you can always eat them!

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