Flathead Catfish (Pylodictis olivaris) are giant fish (up to 60 inches, 130 lbs), and very popular among anglers because of their size and tastiness. They are native to Mississippi and Gulf drainages. These catfish have been stocked or otherwise released into drainages in 18 states. The first Chesapeake Bay release in 1965 was accidental; the Virginia Division of Fish and Game was keeping them in ponds on Hog Island Game Refuge for research when about 50 fish escaped into the James River during a flood. Although only a few fish were released at that time they established sustaining populations. Similarly, only 12 fish were stocked in the Occoquan Reservoir, but that was enough to establish a population. Populations of flathead catfish have been found in many other areas of the Chesapeake watershed, including the Susquehanna River, and it is suspected that small numbers of fish were released by anglers due to their popularity as a sport fish. This species’ ability to colonize river systems, as well as its role as a top predator with an enormous appetite, means that unauthorized stockings by fisherman are a serious problem. Flathead Catfish tolerate a wide range of temperature (4-33¬ C) and brackish water (to 14 PSU). They are popular as gamefishes because of their size, but their predatory impact is a major conservation concern.