McDowall (1990) describes the brown bullhead as a \"stout fish with a thick body and ventrally flattened head. The back is moderately arched and there is a distinct hump behind the head. Four pairs of barbels are present around the mouth, with a single long one at each corner of the mouth, a pair in front of the eyes on the snout, and two pairs beneath the chin. The skin is thick and leathery with a layer of mucuous. Scales are absent. Colouration is a dark brown to greenish olive on the back, with slightly paler sides. The underside of the head and lower jaw are a buttery yellow colour, which pales to a creamy white or pale grey on the belly\".
Resistant to domestic and industrial pollution, therefore able to survive in heavily degraded waters. Reported to bury itself in mud to avoid adverse environmental conditions (FishBase, 2004). Brown bullhead are scavengers as well as predators, locating their prey in the substrate through the use of their sensory barbels (McDowall, 1990). A painful wound can be inflicted by the sharp spines in the fins of brown bullhead catfish if they are not handled carefully. Toxins released by the fish contribute to the pain of the wound (McDowall, 1990).
Found in sluggish, often weedy, streams and rivers. Also occurs in impoundments, lakes, lagoons and ponds. The brown bullhead can tolerate waters with high carbondioxide and low oxygen concentrations, as well as temperatures up to 31.6°C (FishBase, 2004). It can live out of water for long periods if kept moist (McDowall, 2000).
Spawning occurs in a nest, a shallow depression in the substrate, built by one or both parents. Eggs are guarded, with the attendant fish moving them with its barbels and fanning them with its fins to encourage development. Hatching occurs in around a week, with the young dispersing in small shoals. (FishBase, 2004; McDowall, 2000).
Feeds on a wide variety of items including snails, freshwater crayfish, fish eggs, worms, insects (adults and larvae), fish and algae (FishBase, 2004; McDowall, 2000).The main prey of adult brown bull head in Lake Taupo, New Zealand are freshwater crayfish (Barnes, 1996).
Principal source: McDowall, R. M., 2000. The Reed field guide to New Zealand freshwater fishes. Auckland, Reed.
FishBase, 2004. Species profile Ameiurus nebulosus
McDowall, R. M.1990. New Zealand Freshwater Fish a natural history and Guide. Heinmann and Reed MAF Publishing Group.
Barnes, G.E., 1996. The biology and general ecology of the brown bull head catfish (Ameiurus nebulosus) in Lake Taupo. MSc Thesis, University of Waikato, Hamilton.
Rowe, D.K and Graynoth, E, 2002. Lake Managers Handbook- Fish in New Zealand Lakes. Ministry for the Environment, Wellington.
Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement)
Review: Dr. David Rowe, NIWA (National Institute of Water & Atmospheric Research). Hamilton New Zealand.
Publication date: 2006-04-11
Recommended citation: Global Invasive Species Database (2016) Species profile: Ameiurus nebulosus. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=612 on 26-07-2016.