Brown bullhead are notable for their sound production, likely produced by rubbing body parts together. In the lab, they produce sound during aggressive, conspecific encounters. Sound production, thought to be a response to disturbances, was recorded in the field and identified with captured fish. Grouped in the superorder Ostariophysi, they share the derived trait of the alarm response (Shreckstoff).
Communication Channels: acoustic
Perception Channels: visual ; tactile ; chemical
Predators of brown bullhead include northern pike (Esox lucius), muskellunge (Esox masquinongy), walleye (Sander vitreus), snapping turtles (Chelydra serpentina), water snakes (Nerodia species), and green herons (Butorides virescens). Minnows (Pimephales and Notropis species), yellow perch (Perca flavescens), and sunfishes (Lepomis species) are the most common predators on eggs.
Known Predators:
Anti-predator Adaptations: cryptic
Brown bullhead look very similar to black bullhead (Ameiurus melas) and yellow bullhead (Ameiurus natalis). Brown bullhead are distinguished by 5 to 8 large, serrated teeth on their pectoral spines , mottled coloring on their trunk, lack of dark fin rays, and 11 to 15 gill rakers on their first gill arch. An occasional solid colored trunk has been described. They have 8 dark brown to black barbels on their head (two nasal, two maxillary, and four on the chin) which are sensitive to touch and chemical stimuli. The anterior portion of their body is thicker than the posterior portion. The body is scaleless with a brown to black dorsal side and a lighter ventral side. In captivity, this species loses pigmentation, becoming whitish. They have terminal mouths with a slightly longer upper jaw and a mouth filled with irregular rows of tiny teeth on both jaws. However, Baily et al. (2004) described their jaws as being equal. Their head is dorso-ventrally flattened. They have one dorsal fin, an adipose fin, and a caudal fin with a slightly indented fork. Typical adult length is 200 to 300 mm but they may reach up to 500 mm. Adults typically weigh 0.5 kg, but have been recorded at 3.6 kg. No significant difference has been found between male and female size.
Range mass: 3.6 (high) kg.
Average mass: 0.5 kg.
Range length: 500 (high) mm.
Average length: 200-300 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
Brown bullhead live 6 to 8 years. Maximum age of brown bullhead is 9 years. Predation pressure is strongest during the egg and larval stages.
Range lifespan
Status: wild: 9 (high) years.
Average lifespan
Status: wild: 6 to 8 years.
Brown bullhead are found in pools and slower-moving runs of creeks and rivers, reservoirs, ponds, and lakes. They are tolerant of a wide range of environmental conditions, including water temperatures up to 36 degrees Celsius and oxygen levels to 0.2 ppm. They prefer habitats with vegetation and substrate. They survive well in domestically and industrially polluted waters. They are bottom dwelling fish.
Habitat Regions: temperate ; tropical ; freshwater
Aquatic Biomes: benthic ; lakes and ponds; rivers and streams; brackish water
Brown bullhead are native to freshwater habitats in Canada and the United States from 25° to 54° north latitude. They are distributed in the Atlantic and Gulf Slope drainages, ranging from Nova Scotia and New Brunswick to Mobile Bay, Alabama, and in the Great Lakes, Hudson Bay, and Mississippi basins from Quebec west to southeast Saskatchewan and south to Louisiana. Brown bullhead have been introduced outside of this range, including countries of northern, western, and eastern Europe, the Middle East, New Zealand, Chile, and Puerto Rico (U.S.). They have also been introduced and well established in the western United States and British Columbia.
Biogeographic Regions: nearctic (Introduced , Native ); palearctic (Introduced ); australian (Introduced )
Brown bullhead are benthic, opportunistic omnivores. In aquarium settings they eat most food given to them. Juveniles eat zooplankton, including chironomids, cladocerans, ostracods, and amphipods, insects, including mayfly larvae and caddisfly larvae, and plants. Adults feed on insects, small fish, fish eggs, mollusks, plants, leeches, worms, and crayfish. They typically are nocturnal feeders, but have been observed feeding during the day. They use their barbels to locate food.
Animal Foods: fish; eggs; insects; mollusks; terrestrial worms; aquatic or marine worms; aquatic crustaceans; zooplankton
Plant Foods: macroalgae
Primary Diet: carnivore (Piscivore , Eats eggs); omnivore
Brown bullhead are the subject of a small scale recreational and commercial fishery in Canada and in the United States. They have been important research animals for the study of sensory hair cells as well as physiological changes due to temperature, taste, oxygen usage, and osmoregulation. They are also an important indicator species in pollution studies.
Positive Impacts: food ; research and education
There are no known adverse effects of brown bullhead on humans.
Mean daily water temperature during reproduction is 14 to 29 degrees Celsius. Once brown bullhead egg clusters are released and fertilized, they take up to 13 days to hatch, but did so on average at day 5.6 during a study by Blumer (1985). Egg diameter is about 2.2 to 2.7 mm. The larval stage lasts 4 to 9 days, but on average lasted 4.4 days in Blumer's study (1985). Hatched larvae are 4 to 8 mm long, lay on nests during early development, and survive on their yolk-sacs. Metamorphosis occurs between the larval and juvenile stage. Juveniles remain in schools. The average length of the juvenile stage to the end of parental care is 5 days.
Development - Life Cycle: metamorphosis ; indeterminate growth
Brown bullhead are not listed for protection under the IUCN Red List, the United States Endangered Species Program, or under a CITES appendix.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Brown bullhead are predatory fish and prey on other animals.
Brown bullhead are monogamous during the breeding season. Blumer (1985) and Becker (1983) were unable to determine how pairing occurred. Courtship, occurring near nesting sites, involves holding the partners jaw, tail, or head with the mouth, head butting, nibbling bodies, and caressing barbels. Side-by-side swaying has also been observed. Pairs settle over nests and face away from each other during gamete release.
Mating System: monogamous
Brown bullhead spawn once during the spring and early summer breeding season. During an extensive four year study in Michigan by Blumer (1985), this species spawned most frequently within the first 16 days of June. He also found that larger males spawned earlier in the season. In New Zealand, these fish spawn between September and December. They reach sexual maturity at 3 years of age. Nests, typically built by females but sometimes by pairs, are excavations made in the sand, gravel, mud, under roots, and within the shelter of logs and vegetation in shallow water. Substrate is sucked into the mouth and relocated during nest building. Sheltered nests are thought to provide protection from predators. Eycleshymer (1901) noted nests in pieces of stovepipe and a bucket. During nest construction males are territorial. Egg clusters contain 50 to 10,000 eggs. Brown bullhead demonstrate iteroparity. Fertilization is external.
Breeding interval: Brown bullhead spawn once during a breeding season.
Breeding season: The breeding season is during the spring and early summer.
Range number of offspring: 50 to 10,000.
Range gestation period: 13 (high) days.
Average gestation period: 5.6 days.
Average time to independence: 9.4 days.
Average age at sexual or reproductive maturity (female): 3 years.
Average age at sexual or reproductive maturity (male): 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Demersal eggs are incubated and guarded by one or both parents who fan the eggs with their fins, which may minimize fungal infection and help with development. After hatching, larvae on the nest and schooling juveniles are guarded by one or both parents who chase away other fish. If juveniles leave the school, parents will capture them and return them with their mouths. Blumer (1985 and 1986a) found males to be primary caregivers: 56.2% of broods were cared for by both sexes, 39.3% by males only, and 4.5% by females only. Maximum length of parental care is 29 days.
Parental Investment: male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Protecting: Male, Female); pre-independence (Protecting: Male, Female)
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 wawaazisii is one of six beings that came out of the sea to form the original clans.[3]
The brown bullhead grows to be approximately 21 inches (53 cm) in length[4] 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.[5] 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,[6] 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.[7] The fish has eight barbels around its mouth.[8] The barbels on the chin are black to yellowish brown.[9] Juvenile brown bullheads are similar in appearance, but are more likely to be of a single solid color.[5]
The brown bullhead's mouth is terminal[5][8] or slightly subterminal,[5] with the upper jaw projecting slightly past the lower jaw.[6] 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.[5][10] Adult brown bullheads range in size from 200 to 500 mm (7.9 to 19.7 in) and weigh between 0.5 kg (1.1 lb) and 3.6 kg (7.9 lb) (in extreme cases).[8] Brown bullheads are ectothermic, heterothermic, and bilaterally symmetrical.[8] 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.[5]
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).[11] 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.[12] Brown bullheads are a social non-migratory species that are known to form schools.[8]
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.[13] 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 80 °F (27 °C) 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 0.2 ppm.[8] Because of bullheads' tolerance of low oxygen levels, they are less threatened by winterkill and are capable of surviving in relatively extreme environments.[14]
This catfish is easily caught with natural bait such as worms and chicken livers. They have a scrappy but not unusually strong fight. Anglers often catch them by fishing off the bottom. When caught in very clear water when the flesh is firm and reddish to pinkish, the hornpout is quite edible and delicious. Nevertheless, its genial cousins such as the channel catfish and the blue catfish are better known for their use as food. In most areas, they will not exceed two pounds in weight, with a current International Game Fish Association world record of 7.375 pounds (3.345 kg).[15]
Brown bullheads typically live between six and eight years,[8] but have been recorded as old as fifteen in captivity. The species spawns between April and June.[16] For the duration of each breeding season, females will be monogamous.[8] There are no consistent behaviors of mate attraction. The females lay eggs in dark locations such as under rocks and inside logs,[16] where they are externally fertilized by the male.[8] The fish face opposite one another during the fertilization process. Nests are primarily created by females, but the eggs are protected by both sexes. An egg cluster in a nest may contain between 50 and 10,000 eggs.[8] The eggs usually take six days to hatch, but may take up to 13 days. Both parents generally care for their offspring for an additional five days after the eggs hatch.[6] The young are kept in a school by a parent for up to one month. They will remain in schools as juveniles.[8]
Brown bullheads, both male and female, will reach sexual maturity around age three.[8] Brown bullheads have occasionally been recorded eating their own eggs.[17]
The fish has been introduced into many European countries, such as Poland, Germany, Sweden, Norway, Finland, Romania, Estonia, Hungary, Serbia, and Croatia. Brown bullheads have also been introduced to western North America, Chile, Puerto Rico and New Zealand.[18]
Countries who have reported adverse effects from the introduction of the brown bullhead species include Iran and Turkey.[17]
Brown bullheads are omnivorous benthic bottom feeders. Their diet consists of algae, leeches, worms, mollusks, crustaceans, insects, crayfish, other smaller fish species and fish eggs.[8][19] Brown bullheads are typically nocturnal feeders, but have been reported to feed diurnally. Bullheads have poor eyesight and are heavily reliant on their sensitive barbels to locate their food.[8] The fish are omnivorous and will reportedly eat almost anything that fits in their mouth.[14]
Brown bullheads are the most susceptible to predators in their developmental stages, primarily as eggs. They are prey to the following species: northern pike, muskellunge, walleye, snapping turtles, water snakes, green herons, yellow perch, and sunfish.[8] Additionally, brown bullheads are used for small-scale commercial fishing, recreational fishing, and more specifically for consumption and research. Predation by other fish and coexisting species is only a realistic threat to bullheads under four inches, while the biggest threat to adult bullheads is humans. Brown bullheads have protective coloration to avoid predation.[14] As a mode of physical defense against predators, bullhead species have a sharp spine on the leading edge of their dorsal and pectoral fins. To use this adaptation as a defense mechanism, bullheads will stiffen the spine while being attacked, impeding the predator's ability to swallow while simultaneously releasing a venom to sting and burn the predator.[14]
Brown bullheads hold no special status on the International Union for Conservation of Nature and Natural Resources, the United States Endangered Species Program, or under the CITES appendix.[8] Brown bullheads can tolerate very low dissolved oxygen levels that result from industrial and domestic pollution, aiding in their overall high rate of survivorship.[8] Brown bullheads are the most abundant species in many lakes and streams across the continent.
In Missouri, the brown bullhead is listed as a Species of Conservation Concern and is threatened by habitat destruction, particularly the drainage of swamps in the Missouri Bootheel for conversion into farmland.[6]
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 wawaazisii is one of six beings that came out of the sea to form the original clans.
