Ameiurus nebulosus

Occurs in pools and sluggish runs over soft substrates in creeks and small to large rivers. Also found in impoundments, lakes, and ponds. Rarely enters brackish waters (Ref. 1998). A nocturnal feeder that feeds mollusks, insects, leeches, crayfish and plankton, worms, algae, plant material, fishes and has been reported to feed on eggs of least cisco, herring and lake trout (Ref. 1998). Juveniles (3-6 cm) feed mostly on chironomid larvae, cladocerans, ostracods, amphipods, bugs and mayflies (Ref. 1998). Can tolerate high carbon dioxide and low oxygen concentrations and temperatures up to 31.6 °C although experiments show upper lethal temp. to be 37.5 °C; resistant to domestic and industrial pollution (Ref. 1998). Has been observed to bury itself in mud to escape adverse environmental conditions (Ref. 1998). Prepared hot-smoked and also cooked in various ways (Ref. 1998).

Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) This bullhead is native in most of the eastern United States and adjacent southern Canada, west to southeastern Saskatchewan, Nebraska, and Louisiana; it is common in the Northeast and on the Atlantic and Gulf slopes, sporadic elsewhere (Page and Burr 2011). It is widely introduced and established outside the native range.

British Columbia, Canadian Exclusive Economic Zone [Pacific part], Coastal Waters of Southeast Alaska and British Columbia, FAO fishing area 67, New Zealand Exclusive Economic Zone, North East Pacific, North Pacific

North America: Atlantic and Gulf Slope drainages from Nova Scotia and New Brunswick in Canada to Mobile Bay in Alabama in USA, and St. Lawrence-Great Lakes, Hudson Bay and Mississippi River basins from Quebec west to Saskatchewan in Canada and south to Louisiana, USA. Introduced into several countries. Several countries report adverse ecological impact after introduction. Asia: Iran and Turkey (Ref. 39702).

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 )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Southern Canada; eastern and central U.S.A., widely introduced elsewhere in eastern and western North America and in Europe.

Dorsal spines (total): 1; Dorsal soft rays (total): 67; Analspines: 1

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

Maximum size: 500 mm TL

55.0 cm TL (male/unsexed; (Ref. 40637)); max. published weight: 2,740 g (Ref. 40637); max. reported age: 9 years (Ref. 59043)

Length: 53 cm

Caudal fin with 18-19 rays.

This taxon is one of a number of demersal species in the Columbia River system. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton. The Columbia River is the largest North American watercourse by volume that discharges to the Pacific Ocean. With headwaters at Columbia Lake, in Canadian British Columbia, the course of the river has a length of approximately 2000 kilometers and a drainage basin that includes most of the land area of Washington, Oregon and Idaho as well as parts of four other U.S. states and two Canadian provinces.

The Columbia River Basin of northwestern North America is an important habitat for Acipenser transmontanus. The Columbia River is the largest North American watercourse by volume that discharges to the Pacific Ocean. With headwaters at Columbia Lake, in Canadian British Columbia, the course of the river has a length of approximately 2000 kilometers and a drainage basin that includes most of the land area of Washington, Oregon and Idaho as well as parts of four other U.S. states and two Canadian provinces.

The hydrology and aquatic habitat of the Columbia River basin has been adversely altered by numerous large dams. There are over 250 reservoirs and around 150 hydroelectric projects in the basin, including 18 mainstem dams on the Columbia and its main tributary, the Snake River.

Water quality in the Columbia River has deteriorated over the last century, due to agricultural runoff and logging practices, as well as water diversions that tend to concentrate pollutants in the reduced water volume. For example nitrate levels in the Columbia generally tripled in the period from the mid 1960s to the mid 1980s, increasing from a typical level of one to three milligrams per liter. Considerable loading of herbicides and pesticides also has occurred over the last 70 years, chiefly due to agricultural land conversion and emphasis upon maximizing crop yields.

Heavy metal concentrations in sediment and in fish tissue had become an issue in the latter half of the twentieth century; however, considerable progress has been made beginning in the 1980s with implementation of provisions of the U.S.Clean Water Act, involving attention to smelter and paper mill discharges along the Columbia.

Some large demersal fish species occurring in the Columbia Basin are the 610 centimeter (cm) white sturgeon (Acipenser transmontanus), the 76 cm Pacific lamprey (Lampetra tridentata); the 55 cm Brown bullhead (Ameiurus nebolosus); the 61 cm largescale sucker (Catostomus macrocheilus); the 64 cm longnose sucker (Catostomus catostomus catostomus); and the 65 cm Utah sucker (Catostomus ardens).

The Columbia River Basin of western North America is an important habitat for the 55 centimeter (cm) long brown bullhead (Ameiurus nebulosus) The Columbia River is the largest North American watercourse by volume that discharges to the Pacific Ocean. With headwaters at Columbia Lake, in Canadian British Columbia, the course of the river has a length of approximately 2000 kilometers and a drainage basin that includes most of the land area of Washington, Oregon and Idaho as well as parts of four other U.S. states and two Canadian provinces.

The hydrology and aquatic habitat of the Columbia River basin has been adversely altered by numerous large dams. There are over 250 reservoirs and around 150 hydroelectric projects in the basin, including 18 mainstem dams on the Columbia and its main tributary, the Snake River.

Water quality has deteriorated over the last century, due to agricultural runoff and logging practices, as well as water diversions that tend to concentrate pollutants in the reduced water volume. For example nitrate levels in the Columbia generally tripled in the period from the mid 1960s to the mid 1980s, increasing from a typical level of one to three milligrams per liter. Considerable loading of herbicides and pesticides also has occurred over the last 70 years, chiefly due to agricultural land conversion and emphasis upon maximizing crop yields.

Heavy metal concentrations in sediment and in fish tissue had become an issue in the latter half of the twentieth century; however, considerable progress has been made beginning in the 1980s with implementation of provisions of the U.S.Clean Water Act, involving attention to smelter and paper mill discharges along the Columbia.

Other large demersal vertebrate species occurring in the Columbia Basin are the 76 centimeter (cm) Pacific lamprey (Lampetra tridentata), the 61 cm largescale sucker (Catostomus macrocheilus); the 64 cm longnose sucker (Catostomus catostomus catostomus); and the 65 cm Utah sucker (Catostomus ardens). Other large benthopelagic fish in the Columbia are the 63 cm northern pikeminnow (Ptychocheilus oregonensis) and the 45 cm Tui chub (Gila bicolor).

Habitat Type: Freshwater

Comments: Habitat includes ponds, lakes, sluggish creeks and small to large rivers, sloughs, backwaters, and reservoirs. Usually this bullhead occurs in vegetated shallows over sand, rock, mud, or silt (most often soft substrates), in clear to turbid water (Lee et al. 1980, Page and Burr 2011). It may burrow into soft bottoms and become inactive in winter. Eggs are laid in open excavations in sand, gravel, or (rarely) mud, often in shelter of logs, rocks, or vegetation, or in holes, burrows, or debris. Nest made by one or both sexes usually are around shores or in coves or creek mouths.

demersal; freshwater; brackish; depth range ? - 40 m (Ref. 1998)

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

Depth range based on 129 specimens in 3 taxa.
Water temperature and chemistry ranges based on 1 sample.

Environmental ranges
  Depth range (m): 0.06 - 63
  Temperature range (°C): 7.970 - 7.970
  Nitrate (umol/L): 4.522 - 4.522
  Salinity (PPS): 32.029 - 32.029
  Oxygen (ml/l): 6.960 - 6.960
  Phosphate (umol/l): 0.673 - 0.673
  Silicate (umol/l): 3.669 - 3.669

Graphical representation

Depth range (m): 0.06 - 63
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Depth: 0 - 40m.
Recorded at 40 meters.

Habitat: demersal.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Nocturnal and benthic, preferring stagnant waters of swamps and lakes (Ref. 10294, 11243). Common length rarely goes beyond 33 cm SL (245 g at 8 years). Juveniles are carnivores surviving on invertebrates, insect larvae, insects and eggs and larvae of other fishes. The main food of adults consist of crustaceans, small fish and frogs (Ref. 11243).

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

Comments: Bottom feeder. Young eat chironomid larvae and small crustaceans. Adults eat larger insect larvae and fishes, also fish eggs, mollusks, carrion, and plant material (Becker 1983, Moyle 1976).

Brown bullhead are predatory fish and prey on other animals.

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:

• northern pike (Esox lucius)
• muskellunge (Esox masquinongy)
• walleye (Sander vitreus)
• snapping turtles (Chelydra serpentina)
• water snakes (Nerodia species)
• green herons (Butorides virescens)
• minnows (Pimephales species)
• minnows (Notropis species)
• yellow perch (Perca flavescens)
• sunfishes (Lepomis species)

Anti-predator Adaptations: cryptic

Ictalurus nebulosus (Ictalurus nebulosus (brown bullhead)) is prey of:
Salvelinus fontinalis

Based on studies in:
USA: New York, Bridge Brook (Lake or pond)

This list may not be complete but is based on published studies.

Epitheliocystis. Bacterial diseases

Enteric Septicaemia of Catfish. Parasitic infestations (protozoa, worms, etc.)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: This species is represented by a large number of occurrences (subpopulations).

>1,000,000 individuals

Comments: Total adult population size is unknown but probably exceeds 1,000,000.

Moves widely in large lakes, as much as 26 km from point of release (Moyle 1976).

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

Comments: Mostly nocturnal. May burrow into soft bottom and become inactive at low temperatures (Becker 1983).

Nests are built by one or both sexes. After a period of caressing each other with their barbels, male and female settle over the nest, face opposite directions (while maintaining body contact) and spawn. Although eggs are cared for by one or both parents, there have been reports of parents eating their own eggs. Caring entails fanning by the paired fins, moving and stirring by the barbels, and may be picked up and ejected from the mouth; this ensures hatching.

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 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 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 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.

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)

Spawns in late spring and summer. Eggs hatch in 6-9 days. Parents stay with eggs and hatchlings. Usually first breed in third year (Becker 1983, Moyle 1976).

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 14 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 22
Specimens with Barcodes: 69
Species With Barcodes: 1

Rounded Global Status Rank: G5 - Secure

Reasons: Large range extent in central and eastern North america; large population size;stable or increasing trend; no major threats.

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

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Global Short Term Trend: Relatively stable (=10% change)

Comments: Trend over the past 10 years or three generations is uncertain but probably relatively stable.

Global Long Term Trend: Relatively stable to increase of >25%

Comments: Range extent and abundance probably have increased over the long term as a result of introductions outside the native range.

Comments: No major threats are known.

Not Evaluated

fisheries: minor commercial; aquaculture: commercial; gamefish: yes

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

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

Comments: Has been used in carcinogenesis testing (Metcalfe 1989).