Garlov PE*, Bugrimov BS and Rybalova NB
The strength of the baltic population of Atlantic salmon, salmo salar in our North-western region at present is minimal and is supported mainly by Salmon-Breeding Factories (SBF). Factory producers of origin return is about 2% of the total number of released juveniles, which testifies to its low survival rate and the need to improve the biotech cultivation (Reports of the college of the RF federal fisheries agency for periods 2009-2014). The greatest waste factory juveniles occur in the final stages of the biotechnical production and especially when its release into the natural environment. It is customary to explain its lack of survival in the environment because the degrees of development and growth of juvenile fish in the river factory, reaching smoltification. It is important that the occurrence and extent of the freshwater salmon dwarf males among factory juveniles are much higher than in nature. The mass planting material-weight standard of juveniles shall be not less than 30 grams. However, many salmon fish factories in all or a significant portion of the recruit let out it at a much smaller mass. That often explain by the high planting densities due to lack of outgrown (basin) areas.
In recent years, also abnormally high summer temperature, which violate all links the process of reproduction, forcing emergency order to produce non-growth juveniles (fingerlings) sample 2 g-8 g, forcing SBF to release them near their territories. The problem of obtaining enough major planting of enhanced bio-technique development can solve-intensive growing of juveniles. So, more trout farms in north region (Karelia) from 1999 grow up 2-years age lake salmon 23 g-50 g. However, changing the conditions of factorial fry (transportation and containing in cages) markedly increases the departure for several days of acclimation. In our northern region the survival of juvenile salmon (smolts) from release to return is only 0.02%-0.43%, survival at sea is about 0.09%-2.16% and waste in the river is between 32%-93%. Experience of growing factory recruits in sea cages in the ocean salinity (35%) also shows the ineffectiveness of the existing biotechnology her cultivation. This is due primarily to the lack of preparedness of juveniles for release in natural conditions and its replacing into the marine environment, because of the lack of pre-adaptation process (stage).
Published Date: 2023-06-30; Received Date: 2021-05-27
