Blue catfish are native to the Mississippi, Missouri, and Ohio River basins of central and southern United States. They live in Gulf Coast streams from Alabama south to Mexico, northern Guatemala, and Belize. They have also been introduced into other areas and are considered “invasive” in areas such as the Chesapeake Bay.
Blue catfish are a “large-river fish”—they like deep, flowing water and are most common in open waters of large reservoirs and main channels, tributaries, and impoundments of major river systems. Although a freshwater fish, they also thrive in brackish water. They live over various water bottoms, from gravel and sand to silt and mud.
Blue catfish sexually mature around age four of five, or when they’re about two feet long. They spawn from April through June, when water temperatures are at least 70°F. The female lays a mass of eggs in hollow spaces in logs, between rocks, or in other sheltered structures. The male fertilizes the eggs and guards the nest until the eggs hatch and the young leave the nest (after about a week). Blue catfish are very productive—females lay about 10,000 to 60,000 eggs per year.
Blue catfish grow rapidly throughout their lives. In fact, they’re one of the largest catfish in North America and one of the largest freshwater fish. They can grow up to nearly 100 pounds and 5-1/2 feet. There are even reports in the late 1800s of fishermen landing blue catfish larger than 350 pounds from the Mississippi River. However, blue catfish are more common at 20 to 40 pounds and 25 to 40 inches long. They can live up to 20 or 30 years.
Blue catfish are opportunistic omnivores and will eat anything readily accessible. Adults mainly eat fish and shellfish. Blue catfish have few predators, besides birds and other catfish.
Blue catfish look pretty similar to channel catfish, but they do not have dark spots on their back or sides. Their color varies, depending on water quality—they’re typically slate blue on the back shading to white on the belly. Immature blue catfish are usually more silver or silver-white than adults (where they get the name “white cat”). Their tail is deeply forked—in fact, their species name furcatus is Latin for forked. They have large, flat heads and down-turned mouths, adapted for feeding on the bottom. They have a hump on their backs in front of the dorsal fin and long, slim barbels on their chin, like a cat’s whiskers.