RESUMEN
In the Caspian Sea were found typically marine form--Pseudotracheliastes stellatus, specific for Acipenseridae, Thersitina gasterostei typical for sticklebacks rather euryhaline hosts, and Ergasilus briani, E. sieboldi, Paraergasilus rylowi, Lernaea elegans, L. esocina, Caligus lacustris, Argulus coregoni, A. foliaceus and Achtheres percarum normally infested the fishes in fresh water. The last one is characteristic for only Percidae, the remaining fresh-water crustaceans have far more wide host range. The majority of the parasitic crustaceans are noted in the coastal shallow areas of the Caspian Sea. Only P. stellatus is met too in the fairy deep places, where they are brought by Acipenseridae, which perform migrations of considerable extent.