PETROMYZONTIDAE

Family PETROMYZONTIDAE View in CoL

Genus Caspiomyzon Berg 1906

1. Caspian lamprey Caspiomyzon wagneri (Kessler, 1870) .

This is an anadromous, historically valuable commercially important species, endemic to the Caspian Sea basin. It is found throughout the sea, but there are no precise data on its distribution by depth and feeding grounds ( Orlov et al., 2022 a, 2022b). It enters the Volga, Ural, Kura, Terek, Aras and Iranian rivers to spawn, forming independent populations ( Nikitin, 2016). Before the construction of hydroelectric dams, this lamprey migrated into the Volga as far as Tver, the Kama as far as Chusovaya, the Oka as far as the Moscow, the Terek as far as the mouth of the Baksan, the Kura as far as Mtskheta, and the Ural as far as Orenburg ( Bogutskaya et al., 2013). Fishing for Caspian lamprey has been banned since 1997. Currently, this species is listed in the RDBs of the Russian Federation ( Pavlov, 2021), the Astrakhan Region ( Pilipenko et al, 2014), the Republics of Kalmykia ( Ochirov, 2014) and Dagestan ( Magomedov, 2009), as well as Turkmenistan ( Annabayramov, 2011) (category IV with undetermined status) and Kazakhstan ( Meldebekov, 2010) (category II as a species declining rapidly within its range), but has an inappropriate IUCN Least Concern conservation status ( IUCN, 2024). Conservation measures aimed at maintaining the Caspian lamprey population are currently not effective ( Orlov et al., 2022 a, 2022b). The reasons for the decline in Caspian lamprey abundance observed in recent decades include overregulation of the Volga River flow ( Nikitina, 1998), IUU fishing ( Nikitin, 2016), water pollution, dredging and many other factors ( Nazari et al., 2017; Orlov et al., 2022 a, 2022b). The impact of these factors dictates the creation of additional conservation measures.