author(s)
Suleymanov S Sh, Azizov AP and Seyid-Rzayev MM

abstract
On material based on trawling shootings and the netting catches carried out near the western coast of Caspian Sea in 2014 - 2015, and also according to commercial statistics, the periods of spawning migrations of herrings (Alosa) are analyzed. Features of behavior of herrings inhabiting the western shelf of Caspian Sea, including periods, ways and the reasons of their migrations from southern to the northern Caspian are studied. It is shown that environmental factors can influence to some extent the time of the beginning of spawning migration what that might be related to processes of evolution of these species which are shaped by natural selection. It is without doubt that the origin and development of migratory ways are also connected with the geological past of the basin. Dependence of spring migration of herrings from horizontal and vertical migrations of plankton prey is established. For the first time we established connection of external factors of the environment with internal factors and their interactions. Spawning migrations depend not only on external factors, but also on the sexual hormones which actively influence development of gonads.