The locked up salmon is a variety of the salmon of the Atlantic that, according to its biological history developed a form confined to the fresh water in regard to a landslide that disrupted the communication of the Sebago lake, of where they are original, in the coast this of North America. Therefore it is a variety that, instead of migrating to the sea to get fat, remains in the inner rivers or lakes. There are locked up salmons of the Atlantic in lakes of Russia, the United States and Canada. The salmons of the Atlantic migrate to this ocean to continue their growth. Unlike the salmons of the Pacific, they do not die after the first egg-laying, thus they can lay eggs one or two more years.
In our country concerted efforts have become of sowing, those that were successful in very few river basins. One even is in the river basin of the Futaleufú lake and all the chain of lakes of the National Park the Larches, arriving until the lake Cholila (Chubut) and Tigre river. Also in the river and Traful lake, the Huechulaufquen lakes, Epulaufquen and Currhué Grande, in Neuquén, and the river Limay and Embalse Alicurá, in Negro River. In the last years some experiences have been made of sowing in the Grande river, Cordova with poor results.
The salmon is esbelto more than the trout. In proportion, its head is smaller than the body. The trunk and the tail are finer, specially pedúnculo of great volume become thin that allows to hold it by this one, without the fish slips as it happens with all the trouts. The fin of great volume more is forked; that is to say, it presents an average crack. The back is bluish with black, some in form of "xs", although little abundant spots; they are not observed in the fins. When they appear in the opérculos they are little. They are not surrounded by I pull ahead clear like in the brown trout.
They are the fish more coveted by the sport fishermen of our region by its great combat efficiency, by the spectacular jumps that make outside the water and its famous ones "run". Indeed its name, salmon, mean "dancer". The quality of its meat is excellent by the color and proportion of musculatura. As far as the sizes, the locked up salmon is minor who the migrador salmon of the Atlantic , and exceptionally has captured itself exemplary superior to 9 kgs. According to data gathered in a series of lakes that include the Sebago lake (place of origin of this salmon, in Maine , the United States ), the locked up salmon mainly feeds on fish and in a low proportion on insects and aquatic invertebrates. In the Patagonia , the fish constitute a so important component of the diet as the crustaceans and in smaller proportion the aquatic insects and other organisms .