Invertebrate Animals (Metazoa: Invertebrata) from the Bulgarian Black Sea Coast

Description

A total of 19 types, 39 classes, 123 orders, 477 families and 1590 species are known from the Bulgarian Black Sea. They include 1059 species (66.6%) marine and marine-brackish forms and 531 species (33.4%) freshwater-brackish, freshwater and terrestrial forms, connected with water. Five types (Nematoda, Rotifera, Annelida, Arthropoda and Mollusca) have a high species richness (over 100 species). The vertical distribution has been analyzed for 805 species (76.0%) – marine and marine-brackish forms. The marine and marine-brackish species are divided into 162 zoogeographical categories, combined into 4 main groups and 16 subgroups. The main portion of the Black Sea fauna has an Atlantic-Mediterranean origin and represents the impoverished Atlantic-Mediterranean fauna (740 species – 69.9%). Cosmopolitan, Atlantic-Indian, Atlantic-Pacific, endemic and Caspian relict forms are represented. The benthic (115 species – 97.5%) and marine (114 species – 96.6%) forms of the Black Sea endemics (118 species – 11.2%) predominate. The brackish endemics (11 species – 9.3%) most often are Caspian relicts.