Scientific Research Results of Affinity between Anadromous Salmon and Catadromous Trout of Black Sea Kumzha

Abstract

In Georgian Waters inhabit two species of Kumzha and 2 species of trout: anadromous salmon and freshwater catadromous trout of the Black Sea Kumzha inhabit the Black Sea Georgian coastal and water bodies, while anadromous salmon and catadromous river trout of the Caspian Sea Kumzha are common in water bodies of East Georgia. For a long time, scientists recognized anadromous salmon and freshwater trout as two independent species. Today many experiments have proved the transformation of anadromous salmon into river trout and vice versa, the transformation of river or lake trout into true salmon. Anadromous salmon and freshwater catadromous trout of the Black Sea Kumzha are two ecological forms of Black Sea Kumzha, a species of the Salmonidae Family. Through diadromous migrations, there is constant exchange and complementation of genetic and paratypic elements between the catadromous river and anadromous metapopulations. The life cycle of salmons is divided into two periods: sea (fattening) and river (genital products maturation and spawning). Adults typically make annual anadromous migrations to their native river for spawning and spend 6 months there, i.e. as long as in the sea. Conditionally resident trout in rivers and streams live there for only one or two years, then undergo internal osmoregulation, acquire silvery appearance and migrate to the sea. Black Sea Salmon population size and area totally depend on the generations obtained by reproduction of salmon and trout in a spawning river, most of which, after reaching the age of one year, migrate to the sea from early spring to late autumn, thus permanently replenishing and increasing the salmon population. 60-70% of salmon - trout subpopulation in the Georgian coastal rivers are the under yearlings - the single reproduction fund of migrating and resident ecotypes of Black Sea Kumzha.