Investigations on spawing, eggs and fry of fish form a separate and important section of scientific work on fisheries, demanding special methods and attack.
As a rule the chief spawning occurs in places with a specific temperature for every species, respective salinity, depth and bottom.
The quantitative distribution of eggs in sea water r-eflects the distribution of spawning shoals.
The finding of newly spawned eggs in the sea allows to judge on grounds, conditions and intensity of spawning.
Besides, the investigation of eggs and fry of fishes may be of some avail in general oceanographical investigations, the direction of the currents being shown by the drifting fry of the fish.
In accord with the importance of the said investigation a Laboratory for the study of Fish Eggs and Larvae was organized by the author in the Institute of Marine Fisheries and Oceanography (formerly Oceanographical Institute) of USSR in the year 1930.
Numerous catches of fish eggs and larvae were organized on expedition ships "Persey", "Knipovich", "Loshkin" a. o., covering the whole Barents-Sea basin.
On the basis of the work performed by the above Laboratory we may already form some judgement on the basic moments of the Natural History of Food Fishes of the Barents-Sea.
The majority of the main food fishes of the Barents-Seaall Gadidae and Pleuronectidaehave pelagic eggs1). The herring, l ) Except Gadus navaga, whose eggs are not floating.