The brown trout is a salmonid and is also known as German brown trout, German trout, Lochleven trout, or European brown trout.

Distribution

Brown trout naturally occur throughout Europe and western Asia. They range from Finland south to North Africa, west to Iceland and as far east as Afghanistan. Introduced throughout the world, they were first placed in Canadian waters in 1890. Today they are found in rivers, lakes and coastal areas in much of North America, and all provinces except Manitoba, Prince Edward Island, and the Northwest Territories.

Sea-run populations occur in Atlantic Canada and Quebec.

Physical Characteristics

Brown trout get their name from the brown or golden brown hue on their bodies. Here are some other characteristics:

• their sides are silvery or yellow and bellies are white or yellowish;

• dark spots, sometimes encircled by a pale halo, are plentiful on the back and sides;

• spotting also can be found on the head and the fins along the back;

• rusty-red spots also occur on the sides;

• the small adipose (or fatty) fin in front of the tail has a reddish hue;

• sea-run brown trout have a more silvery coloration and the spotting is less visible.

• They closely resemble Atlantic salmon and rainbow trout, but salmon have no red coloration on the adipose fin and rainbow trout have lines of black spots on the tail. Young brown trout (parr) have 9-14 dark narrow parr marks along the sides and some red spotting along the lateral line.

• Brown trout can grow to be quite large, especially sea-run fish. Fish weighing up to 31 kg (68 lb) have been recorded in Europe and a specimen weighing 13 kg (28.5 lb) was caught in Newfoundland. Typically they range 2.3-3.2 kg (5-7 lb) but reach 5.9 kg (13 lb) in Guysborough Harbour.

Apart from moving upstream to spawn, adults tend to stay at the same place in a river with very little movement to other stream areas. They can be found at these stations day after day, even year after year! Others move to or from estuaries in the spring or fall. The closest relative of the brown trout is the Atlantic salmon (Salmo salar). The brown trout's name (Salmo trutta) means salmon trout.

The largest brown trout ever taken was hooked recently in Arkansas, U.S.A., weighing just over 40 pounds.

Natural History

Brown trout prefer cool clear rivers and lakes with temperatures of 12-19øC. They are wary and elusive fish that look for cover more than any other salmonid. In running waters they hide in undercut banks, instream debris, surface turbulence, rocks, and deep pools. They also take shelter under overhanging vegetation.

Brown trout are meat-eaters (carnivorous). They eat insects from water and land, and take larger prey such as worms, crustaceans, mollusks, fish, salamanders, and frogs as their size increases.

Brown trout spawn in the fall and early winter (October to February) at the same time speckled trout spawn, or later.

They return to the stream where they were born, choosing spawning sites that are spring-fed headwaters, the head of a riffle, or the tail of a pool. Selected sites have good water flows through the gravel bottom. The female uses her body to excavate a nest (redd) in the gravel. She and the male may spawn there several times. A 2.3 kg (5 lb) female produces about 3400 golden Coloured eggs that are 4 to 5 mm in diameter. Females cover their eggs with gravel after spawning and the adults return downstream. The eggs develop slowly over the winter, hatching in the spring. A good flow of clean, well-oxygenated water is necessary for successful egg development.

After hatching, the young fish (alevins) remain buried in the gravel and take nourishment from their large yolk-sacs. By the time the yolk-sacs are absorbed, water temperatures have warmed to 7 to 12øC. The fish (now known as fry) emerge from the gravel and begin taking natural food.

Brown trout fry are aggressive and establish territories soon after they emerge. They are found in quiet pools or shallow, slow flowing waters where older trout are absent. They grow rapidly and can reach a size of 165 mm (6-5 in) in their first year.

Yearling brown trout move into cobble and riffle areas. Adults are found in still deeper waters and are most active at night. They are difficult to catch and are best fished at dawn or dusk. Brown trout living in streams grow to about 1.8 kg (4 lb), but lake dwellers and sea-run fish grow larger. They mature in their third to fifth year and many become repeat spawners.

In sea-run populations, brown trout spend 2 to 3 years in freshwater then migrate downstream to spend 1 or 2 growing seasons in coastal waters near river mouths and estuaries. There they feed on small fish and crustaceans. Most return to their home streams to spawn, but some straying occurs. Brown trout live up to 14 years and can spend as long as 9 years in the sea.

Published With Funding from the Canada-Nova Scotia Cooperation Agreement on Economic Diversification, Resource Competitiveness Program.