Brown Bullhead Catfish Habits

Development

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

Reproduction

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

Mating System: monogamous

Brown bullhead spawn once during the spring and early summer breeding season. During an extensive four year study in Michigan, 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. 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 time to hatching: 13 (high) days
• Average time to hatching: 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

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. Studies have shown 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.

Behavior

Brown bullhead are a non-migratory species. They are social fish that spend time in schools.

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

Communication & Perception

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 Ostariophysian, they share the derived trait of the alarm response.

• Communication Channels: acoustic
• Perception Channels: visual, tactile, chemical 

Food Habits

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.

• Primary Diet: carnivore, piscivore, eats eggs, omnivore
• Animal Foods: fish, eggs, insects, mollusks, terrestrial worms, aquatic or marine worms, aquatic crustaceans, zooplankton
• Plant Foods: macroalgae

Predation

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.

Economic Importance for Humans: Positive

Brown bullheads 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

Economic Importance for Humans: Negative

There are no known adverse effects of brown bullhead on humans.