The Brown Bullhead is native to New York and can be found in large lakes to small ponds and slow-moving streams. It remains one of the most widely distributed native catfish in the state.
The fish has a dark brown-green dorsal, 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. There are eight barbels around its mouth. Adult brown bullheads range in size from 7.9 to 19.7 in and weighs between 1.1 and 7.9 lbs. Brown bullheads are 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 and their 21–24 anal fin rays.
Habitat
In many areas of the United States, brown bullheads are opportunistic bottom feeders. The species has few natural predators. Catfish 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.
Life cycle and reproduction
Brown bullheads typically live between six and eight years, but have been recorded as old as fifteen in captivity. The species spawns between April and June. For the duration of each breeding season, females will be monogamous. 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]
As an invasive species
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]
Diet
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][16] 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]
Predation
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, largemouth bass, 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 (10 cm), 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]
Conservation
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.[citation needed]
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]