Scientific name: Salmo salar sebago
Other names: salmón encerrado.
Until 1868, landlocked salmon population existed in only four rivers in Maine State: St. Croix River, including West Grand Lake in Washington County, Union River, including Green Lake in Hancock County, the Penobscot River, including Sebec Lake in Piscataquis County and the Presumpscot River, including Sebago Lake in Cumberland County.
At present, there are landlocked salmon in 176 lakes of the U.S., mainly in Maine, one of the largest sport fisheries for this species in the world. This fish needs to be farmed as populations are not big enough for sport fishing, reason why restocking measures must be followed in order to avoid their disappearance.
Weight and measures: As landlocked salmon remains in freshwater and never migrates to the sea, it is smaller than the Atlantic salmon. Adult fish average size varies from 16 to 24 inches, and can weigh 1 to 3 pounds. However, it is not rare to find larger fish, as happened in Traful River –Argentina, where a 20 pound salmon was caught.
Distribution: The landlocked salmon is native of the United States. In Argentina, eventhough its population has greatly diminished, it can still be found in some environments such as: Traful Lake, Traful River, Meliquina Lake, Futaleufu Lake, the entire chain of lakes and rivers of the Alerces National Park, Cholila Tigre River, Cholila Tigre Lake, Huechulaufquen Lake, Currhué Grande Lake, Epulaufquen Lake, rarely in the Limay River and Alicurá Reservoir in Rio Negro.
As regards worldwide distribution, is found in some lakes in Russia, the United States and Canada.
Habitat and life cycle: As a freshwater salmon fish, it never migrates to the Atlantic Ocean; it migrates from river to lakes between the ages of 1 to 4 years.
Most males reach sexual maturity after 3 or 4 years of life, and females when they are between 4 and 5 years. If compared to farmed salmons, wild populations have slower growth rates and shorter lives. The oldest landlocked salmon on record in Maine was 13 years old.
Features: It is more slender than the trout. Its head is small, the trunk and tail are fine tuned, especially the caudal peduncle, and the caudal fin is forked in a pronounced "V" shape.
Adults are generally silvery with bluish back and small X-shaped markings on the back and upper sides. Note that these spots are not surrounded by a clear halo as in brown trout. Juvenile salmon have a dark red spot between each pair of marks. Mature males develop a “kype,” or hooked jaw, during the spawning season, reason why they can also be taken as a brown trout.
Diet: Landlocked salmon feeds mainly on fish (rainbow trout are the main forage species in Maine lakes, so we assume that something similar happens in Argentina), and a low proportion of insects and aquatic invertebrates. In Patagonia, these salmon’s main diet components are fish and crustaceous, while insects and other aquatic organisms are secondary.
