Porcine spawning is the process of hatching eggs in several stages, in separate portions that mature sequentially. Each portion is timed to coincide with the time of increased food availability of the hatched juveniles. The interval between the laying of individual portions is equal to the duration of the first stage of larval development. This phenomenon is peculiar mainly to fish of the tropics and subtropics, in temperate latitudes portion spawning is established in crucian carp, bleak, ruff, to a lesser extent in bream, Caspian herring, and in the Arctic there are almost no portion spawning fish.