Towards the Establishment of Marine Protected Areas in the Russian Part of the Caspian Sea: Marine Distribution of the Most Threatened Cyclostomes and Bony Fishes

Conserving the biodiversity of the Caspian Sea aquatic biota, given its high endemism, is of not only regional but also of global importane against climate change, sea level fluctuations, and increasing anthropogenic impact. Particular attention should be paid to the Caspian Sea ichthyofauna, a key component of the ecosystem. It is economically significant and has experienced considerable natural and anthropogenic pressure in recent decades. In the current situation, the establishment of Ecologically or Biologically Significant Marine Areas (EBSAs) is particularly important among comprehensive measures aimed at conserving the Caspian Sea biological resources. The spatial distribution and migration patterns of threatened anadromous fish species have been well studied within their spawning (freshwater) ranges. However, the distribution patterns of these species at sea during their feeding season (particularly non-sturgeon species) remain virtually unknown, hindering the development of measures aimed at protecting their marine populations. This paper attempts to map and describe the distribution of single species of cyclostomes (Caspian lamprey Caspiomyzon wagneri) and seven species of bony fishes (Volga shad Alosa volgensis, Caspian barbel Luciobarbus caspius, Bulatmai barbel Luciobarbus capito, Aral barbel Luciobarbus brachycephalus, Caspian vimba Vimba persa, Caspian inconnu or sheefish Stenodus leucichthys, and Caspian trout Salmo caspius) in the marine part of the Caspian Sea adjacent to the coast of the Russian Federation based on all available information (published and from open public databases). The presented data may serve as the basis for establishing EBSAs in Russian waters of the Caspian Sea in areas where populations of the aforementioned species are most vulnerable.