In contrast to Atlantic salmon that migrate at sea, the landlocked salmon is a freshwater form that remains in lakes. The French name, ounaniche, means “little lost one” or “he who is everywhere” in Montagnais.
Highly prized by sports anglers for their spectacular jumps, landlocked salmon are found throughout the regions occupied by sea-run salmon in Canada.
- Taxonomy -
- Salmo salar ouananiche McCarthy, 1894
- Common name
- Landlocked salmon
- Physiology -
The body of the landlocked salmon is elongated with slightly compressed flanks, like the Atlantic salmon, but somewhat smaller, averaging 0.9 to 1.8 kilograms.
Landlocked salmon have brown, green or blue backs with many small black spots. The sides are silvery and the dorsal fin also has large black spots. During the spawning season, the colouring becomes more bronze and the males develop red spots on the body. After spawning, the skin turns darker, almost black.
- Life cycle -
The life cycle of landlocked salmon can be divided into three phases:
Returning to the river
In early summer, landlocked salmon return to the river where they were hatched.
Selecting the spawning grounds
Landlocked salmon leave the pools of the river to move to the spawning grounds upstream, seeking areas with shallow water, a swift current and a gravelly bed.
Males are distinguished from females by their “kype,” a pronounced upward hook of the extended lower jaw. While the females are locating favourable spawning spots, the males will attempt to establish a territory around each female. Only the most aggressive males manage to defend their territory against the tireless attempts of other males to approach the females despite continuously being chased away by the dominant males. Violent confrontations between males are sometimes observed.
Preparing the redd
At the spot she chooses, the female digs several “redds” in the gravel, each about 10 to 20 centimetres deep. With a quick, strong fanning movement of her tail, she tosses the gravel up. The current washes the gravel disturbed by the females, so groups of redds in spawning grounds can be easily recognized by the pale yellow colour of this washed gravel.
During spawning, the male and female are positioned side by side. The male’s whole body shakes or quivers as he stretches and gapes. Thus stimulated, the female does the same. When the quivering subsides, the female deposits her eggs and the male fertilizes them by releasing his milt.
Protecting the eggs
Each female lays between 1,500 and 1,800 eggs (5 to 7 mm in diameter) per kilogram of body weight. She covers them with gravel to prevent other species from devouring them.
Returning to the lake
After spawning, landlocked salmon return to the lake or spend the winter in a pool of the river, only moving downstream to the lake in the spring.
Growth in the stream
Buried under the gravel and oxygenated by the water constantly flowing through the gravel bed, the eggs deposited in the fall will develop all winter. However, in addition to predators, many dangers await the eggs: fungi; fine sediments filling the interstices between the gravel; freezing of the eggs; and scraping of the riverbed by ice.
The eggs hatch in May, releasing the tiny alevins. The alevins burrow a little deeper into the gravel, which keeps them safe from being carried away by ice scraping the bottom of the riverbed during the spring break-up. They stay buried for about five to six weeks while being nourished by their attached yolk sac. In June, the fry emerge from the gravel and begin to feed on small insect larvae. They frequent shallow areas of the river where the current is weak. At this stage, many fry become victims of predation.
The first year of growth
At the end of their first summer, the fry are about 5 centimetres long and are now called “parr.” Needing more food, they spend more time in rapids and whitewater habitats where insect larvae are carried by the strong currents. Parr are well adapted to this environment, with well-developed fins that allow them to stay at the bottom of the river, waiting for prey. They become progressively territorial as the season advances. Those that do not fall victim to predation will spend the winter buried under large pebbles and stones.
The subsequent years of growth
The parr will remain in the river for two to seven years. After reaching 12 to 18 centimetres in length, they prepare to move downstream to the lake. At this stage, they are called smolts. They also memorize the scent of their river at this stage, and develop the silvery colouring that is almost identical to that of adults.
Growth in the lake
Migration in the lake
After the downstream migration, the smolts remain in the lake feeding on the abundant resources in these waters that allow them to grow rapidly.
Return to natal rivers
After one to three years in the lake, instinct drives the salmon to return to the river where they hatched in order to spawn. Guided by currents and other mechanisms that remain obscure (stars, magnetic fields), they approach their natal river where the scent finally guides them home.