The fact that some species of fish are capable to postpone until several million berries for one spawning is considered well-known. But what requires such huge amount of caviar?
The majority of species of fish does not burden itself with care of posterity. Having gathered for a spawning area, females just release in ovum water, and males impregnate them. As a result, percent of the survived larvae it is insignificant it is small. From all berries postponed by females have chance to turn into adult fishes only 3-4. Germs become food for adult fishes, perish because of the shortage of oxygen, caviar dries up during otliv. Often larvae are the cast waves ashore.
It is clear, that at such approach, preservation of population of fishes requires huge amount of vymetanny caviar. The catfish and a pike are capable to postpone for spawning on 100 thousand berries, a bream - 250 thousand. The burbot throws to five, and a crash up to nine million berries for once. In order that berries of the fishes who are not caring for the posterity had chance to survive, they are in a certain way adapted for the environment. At the majority of the fishes spawning on fast currents, caviar has glutinosity. Thanks to it larvae stick to stones, plants or soil, as allows them to remain in the water environment. Only some species of fish take parental care of the posterity. And, as a rule, males, but not females fulfill a parental duty. Some males I do special poles at the bottom, and invite females to lay in them caviar. After that they carefully protect the posterity until larvae are removed. Males blow in caviar fins, put away litter and the died berries. At other species of fish the males go further away - they build the real nests in sinks, crevices and small caves. At some breeds the males just store caviar in a mouth. Owing to such care, the number of the surviving whitebaits is rather great. Therefore just such species of fish also do not differ in special fertility - they can lay off from dozens to hundreds of berries for once.