The current state of Atlantic salmon reproduction in the Keret River, White Sea basin, and how it can be increased

Abstract

The Keret River is one of large salmon rivers in the White Sea basin. The estimated abundance of Atlantic salmon in the river began to decrease in 1991, reaching a maximum in 1997 due to the abruptly increased illegal fishing level and the invasion of juvenile Atlantic salmon by the monogeny of Gyrodactylus salaris. The studies conducted have shown that the salmon population in the Keret River is depressed and that the average distribution density of juveniles aged 1+ and older is 1.6 fish / 100 m2. Atlantic salmon reproduction on fish hatcheries is important for maintaining the population abundance (farm individuals make up over 50% of the population). Artificial Atlantic salmon reproduction in the Republic of Karelia’s rivers is carried out by the Karelian Branch of Glavrybvod FGBU at the Kem and Vyg fish hatcheries. The fish hatcheries could achieve better results by updating the juvenile breeding technology. An example of a new high-intensity biotechnology is the use of physical factors controlling the vital activity of fish in the various periods of ontogenesis. The study of the effect of low-intensity laser radiation in the early stages of ontogenesis has shown that red light over a certain dose range enhances the adaptability of fish by decreasing mortality and accelerating growth, thus decreasing the loss of fish products in fish hatcheries.