Brown Trout, Salmo trutta Linnaeus 1758


Other Names: Brownie, Loch Leven Trout, Sea Trout

Brown Trout, Salmo trutta. Source: Eric Engbretson / U.S. Fish and Wildlife Service. License: Public Domain

Summary:

Brown Trout are one of the most popular angling fishes in southeastern Australia. First introduced into Tasmania from the United Kingdom in 1864, the species is now abundant in cool streams, lakes and reservoirs of south-eastern and south-western Australia. Although they breed in the wild, Brown Trout are regularly stocked to maintain populations for recreational anglers.

Unfortunately trout are voracious predators on smaller native Australian fishes.

Stunning footage of from New Zealand showing Brown Trout leaping from the water to catch damselflies.


Cite this page as:
Martin F. Gomon & Dianne J. Bray, Salmo trutta in Fishes of Australia, accessed 20 Nov 2018, http://fishesofaustralia.net.au/home/species/3625

Brown Trout, Salmo trutta Linnaeus 1758

More Info


Distribution

Native to the temperate coastal North Atlantic from Scandinavia to North Africa and east to the Caspian Sea. Known in temperate waters of Australia from north-east New South Wales, the ACT, Victoria, Tasmania to South Australia and south-western Western Australia.

Although Brown Trout inhabit cool, well oxygenated waters, preferring gravelly streams with moderate to swift flow, they are also found in cool, clear lakes and reservoirs. Individuals living in coastal streams occasionally migrate seawards, and anglers in Port Phillip Bay, Victoria have caught sea-run Brown Trout.

Features

Meristic features: Dorsal fin 12-15; Anal fin 10-12; Caudal fin 19; Pectoral fin 12-14; Pelvic fin 9-10; Gill rakers 14-17; Vrtebrae 56-61  

Body moderately deep greatest body depth at dorsal fin origin, 20-24% TL; Caudal peduncle deep; head large, 23% TL; mouth terminal, moderate to large, extending back below eyes; eyes moderate to large, 16-18% of head length in adults; snout rounded; mature and spawning males develop elongated jaws, the lower with a markedly upturned tip (kype) which fits into a groove in upper jaw; teeth developed on upper and lower jaws (pre-maxillary, maxillary, dentary), usually many teeth on head and shaft of vomer, on pala­tines, on tongue in 2 rows, no hyoid teeth. Scales cycloid, small, 120-130 in lateral line. Dorsal fin high on back originating in front of ventral fins; fleshy adipose fin behind dorsal; anal fin short-based, below adipose fin, rounded; caudal fin truncate to square, shallowly forked in young; ventral fins abdominal, relatively small, square to rounded with axillary process at base; pectoral fins long, rounded to somewhat pointed, inserted low on sides.

Size

Although Brown Trout may grow to 140 cm TL and weight of 20 kg in Europe, in Australia, most grow to 90 cm with a maximum weight of 14 kg. Brown Trout may live for 12 years.

Colour

Colour varies with habitat, age and diet. Brown Trout are usually brown or olive overall and may appear silvery (darker on the upper body), with dark spots on the sides (sometimes indistinct), dorsal fin and gill covers. The tail has few if any spots. The body is paler below the mid-line, and most spots are surrounded by a pale halo and are often reddish. Sea-run individuals are olive brown on top, with silvery sides and only a few indistinct spots.

Feeding

Carnivores, feeding on a variety of insect larvae, snails and insects falling from above, aquatic crustaceans and small fishes including native species such as galaxiids and Nannoperca.

Biology

The sexes are separate and fertilisation is external. Female Brown Trout mature at 3 years and males at 2-3 years. Trout migrate upstream to spawn in well-oxygenated gravelly stream beds during winter and early spring. Females make small depressions or holes in the gravel and lay between 500-3000 eggs above each hole (called a ‘redd’).

The eggs are fertilised by a male before they sink into the red. The females then covers them with gravel for protection. The eggs are large, 4-5 mm in diameter, and take 6-20 weeks to hatch, depending on water temperature. The young remain in the gravel for some time absorbing their yolk, before emerging to form small shoals in moderately swift water and commence feeding.

Fisheries

Brown Trout support major recreational fisheries in New South Wales, Victoria, South Australia. The species is one of the most popular recreational freshwater fish throughout southeastern Australia. There is no commercial fishery for Brown Trout.

Government and private hatcheries in New South Wales, Victoria, Tasmania, South Australia and Western Australia breed Brown Trout using aquaculture techniques. Juvenile trout are stocked into streams, lakes and reservoirs to maintain populations for recreational anglers.

The ACT, NSW, Qld, SA and Vic all have legal size limits and catch limits, and Brown Trout cannot be caught during parts of the year in the ACT, NSW and Vic.

Remarks

In 1864 Brown Trout were successfully introduced into what is now called the Salmon Ponds near Hobart, Tasmania. Through migration and stocking programs, the species spread over time into streams, lakes and reservoirs throughout Tasmania and mainland Australia.

Similar Species

As juveniles, Brown Trout are easily confused with juvenile Rainbow Trout, Oncorhynchus mykiss. In life, the adipose fin (the small fleshy fin behind the dorsal fin that lacks rays or spines) of small Rainbow Trout may be spotted with a black margin, and may also be slightly transparent. In contrast, the adipose fin of juvenile Brown Trout is never spotted, is not transparent and may have an orange to reddish dorso-posterior border.

Species Citation

Salmo trutta Linnaeus, C. (1758). Systema Naturae: 308. Type locality: European rivers.

Author

Martin F. Gomon & Dianne J. Bray

Brown Trout, Salmo trutta Linnaeus 1758

References


Allen, G.R. 1989. Freshwater Fishes of Australia. T.F.H. Publications. Pp. 240.

Allen, G.R., Midgley, S.H. & M. Allen. 2002. Field Guide to the Freshwater Fishes of Australia. Western Australian Museum. Pp. 394.

Arthington, A.H. 1991. Ecological and genetic impacts of introduced and translocated freshwater fishes in Australia. Can. J. Fish. Aquat. Sci. 48(Suppl. 1): 33-43.

Cadwallader, P.L. 1996. Overview of the impacts of introduced salmonids on Australian native fauna. Prepared for the Australian Nature Conservation Agency.

Closs, G.P. & P.S. Lake. 1996. Drought, dofferential mortality and the coexistence of a native and an introduced species in a south east Australian intermittent stream. Env Biol of Fishes 47: 17-26.

Crowl, T.A., Townsend, C.R., McIntosh, A.R. 1992. The impact of introduced brown and rainbow trout on native fish: the case of Australasia. Reviews in Fish Biology and Fisheries 2: 217-241.

Davies, P.E. 1989. Relationship between habitat characteristics and population abundance for brown trout, Salmo trutta L., and blackfish, Gadopsis marmoratus Rich., in Tasmanian streams. Aust. J. Mar. Freshwater Res. 40; 341 – 359.

Davies, P.E. & R.M. McDowall. 1966. In McDowall, R.M. (ed.) Freshwater Fishes of South-Eastern Australia. Reed Books. Pp. 247.

Jackson, P.D. 1978. Benthic invertebrate fauna an feeding relationships of brown trout, Salmo trutta Linnaeus, and river blackfish, Gadopsis marmoratus Richardson, in the Aberfeldy River, Victoria. Aust. J. Mar. Freshwater Res. 29:725-742.

Jackson, P.D. & W.D. Williams. 1980. Effects of brown trout Salmo trutta L., on the distribution of some native fishes in three areas of southern Victoria. Aust. J. Mar. Freshwater Res. 31; 61-67.

Lintermans, M. 2004. Human-assisted dispersal of alien freshwater fish in Australia. New Zealand Journal of Marine and Freshwater Research 38: 481-501.

Lintermans, M. 2007. Fishes of the Murray-Darling Basin: an introductory guide. Murray-Darling Basin Commission, Canberra. 166 p.

Merrick, J.R. & G.E. Schmida. 1984. Australian Freshwater Fishes. Biology and Management. John R. Merrick. Pp. 409. Mar. Freshwater Res. 29: 725-742.

Raadik, T. 1993. A research recovery plan for the Barred Galaxias Galaxias fuscus Mack 1936, in Southeastern Australia. Unpublished Report for Endangered Species Program of the Australian National Parks and Wildlife Service. Department of Conservation and Natural Resources, Victoria. 37 pp.

Raadik, T.A. 2008. Family Salmonidae Trouts, Salmon. In Gomon, M.F., Bray D., & Kuiter, R.H. (eds.) The Fishes of Australia's Southern Coast. Reed New Holland and Museum Victoria, 928 pp.

Sanger, A., Fulton, W. 1991. Conservation of endangered species of freshwater fish. Inland Fisheries Commission, Tasmania. Occassional Report No 91-01. 29 pp.

Tilzey, R. D. J. 1976. Observations on interactions between indigenous Galaxiidae and introduced Salmonidae in the Lake Eucumbene catchment, New South Wales. Aust. J. Mar. Freshwater Res. 27: 551-564.

Western Australia Fisheries. 2002. The translocation of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) into and within Western Australia. Fisheries Management Paper No 156. Dept of Fisheries WA.

Quick Facts


CAAB Code:37094004

Fishing:Popular angling fish

Habitat:Clear freshwaters

Max Size:140 cm TL (in Europe)

Max weight:20 kg (in Europe)

Native:Non-native

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