Salmon fishes of the Salmo genus are the important object for fishing, artificial breeding and sport fishing. Currently, for some reasons, the size of the salmon population is in a depressed state. For some salmon fish population in the north of Russia became possible to solve some problems of their preservation with the development of artificial reproduction. However, the quality of juvenile salmon reproduced in the factory, the transportation and release of juveniles are not effective enough therefore the most of the fishes die after release them into natural water soon. The cause of their death is the lack of physical strength and endurance of juveniles in river conditions. At present moment the normative criterion for the quality of juveniles is a hinge of released fishes. One of the alternatives for assessing the quality of whitebaits can be the use of device “Fish Sprint”, whose action is based on the registration of the traction force by a dynamometer developed during the fish motor reaction to the anode in response to the action of a direct or current electric field (anode reaction). Researches have shown that the pulling power of fishes changes significantly in the seasonal aspect and determines primarily by the temperature of the habitat. For juvenile Atlantic salmon it is observed a gradual increase of physical strength at a temperature from 3.5 to 16 ° C, and in the future the pulling force remains almost unchanged. The physical strength of wild spotted trout (age 2+ - 4+), living in river conditions, was higher, compared with factory ones of Atlantic salmon. Salmon juvenile with the same morphological indicators of length and mass, living in natural conditions (rivers) develops physical strength higher twice in comparing juvenile grown in the factories.