The brown bullhead (Ameiurus nebulosus) is a fish of the family Ictaluridae that is widely distributed in North America. It is a species of bullhead catfish and is similar to the black bullhead (Ameiurus melas) and yellow bullhead (Ameiurus natalis). It was originally described as Pimelodus nebulosus by Charles Alexandre Lesueur in 1819, and is also referred to as Ictalurus nebulosus.
The brown bullhead is also widely known as the "mud pout", "horned pout", "hornpout", or simply "mud cat", a name also used with the other bullhead species.
The brown bullhead is important as a clan symbol of the Ojibwe people. In their tradition, the bullhead or is one of six beings that came out of the sea to form the original clans.
Appearance
The brown bullhead grows to be approximately in length and is a darker brown-green dorsally, growing lighter green and yellow towards the ventral surface. The belly is off-white or cream, and the fish has no scales. Additionally, there are darker, brown-black speckles along the entire surface of the fish. The brown bullhead has a dorsal fin that bears a spine, a single adipose fin posterior to the dorsal fin, abdominal pelvic fins, and an anal fin with 21 to 24 rays. The tail is only slightly notched, with the dorsal and ventral lobes angling inward. The pectoral fins have spines that bear 5-8 serrated teeth on their posterior edge. The fish has eight barbels around its mouth. The barbels on the chin are black to yellowish brown. Juvenile brown bullheads are similar in appearance, but are more likely to be of a single solid color.
The brown bullhead's mouth is terminal or slightly subterminal, with the upper jaw projecting slightly past the lower jaw. This position enables bottom feeding. The brown bullhead may be distinguished from flathead catfish (Pylodictis olivaris) by the absence of lateral posterior extensions on the tooth patch of the brown bullhead's upper jaw. Adult brown bullheads range in size from and weigh between and (in extreme cases). Brown bullheads are ectothermic, heterothermic, and bilaterally symmetrical. Brown bullheads can be distinguished from black and yellow bullheads by their yellow-black chin barbels, the absence of a hypopigmented bar at the base of the tail (which is present in black bullheads), and their 21–24 anal fin rays.
Distribution
The native range of the brown bullhead is in the Atlantic and Gulf Slope drainages. More specifically, it is found from Nova Scotia and New Brunswick to Mobile Bay, Alabama, and in the Great Lakes, Hudson Bay, and Mississippi River basins (from Quebec to Saskatchewan, south to Louisiana, and west to Texas). However, there is evidence that the brown bullhead was historically absent from the Gulf Coast west of the Apalachicola River and east of the Mississippi River. The species is also abundant in many regions as a result of stocking for food or sport. These locations include Georgia, Alabama, Arizona, Arkansas, California, Colorado, Hawaii, Idaho, Kansas, Kentucky, Louisiana, Maine, Missouri, Nebraska, Nevada, New Hampshire, New Mexico, Ohio, Oklahoma, Oregon, Virginia, and Washington. Brown bullheads are a social non-migratory species that are known to form schools.
Habitat
The brown bullhead thrives in a variety of habitats, including lakes, ponds, and slow-moving streams with low oxygen or muddy conditions. In many areas of the United States, brown bullheads are opportunistic bottom feeders. The species has few natural predators and is not popular with fishermen, so it has thrived. Catfish are found in a variety of habitats, from lakes or murky ponds to drainage ditches. They are scarce during the day, but come out at night to feed, searching the bottom of a lake or river for food. They eat insects, leeches, snails, fish, clams, and many plants. They are also known to eat corn, which can be used as bait. Similarly to other catfish, they spawn only after the temperature of the water has reached in June and July. However, cooler temperatures are required before brown bullheads will spawn in the northern US. Brown bullheads can withstand a wide range of water temperatures and low oxygen levels. Brown bullheads can survive waters with heavy pollution and dissolved oxygen values as low as 0.2ppm. Because of bullheads' tolerance of low oxygen levels, they are less threatened by winterkill and are capable of surviving in relatively extreme environments.