Interspecific hybridization in natural sturgeon populations of the Eastern Black Sea: the consequence of drastic population decline?

Abstract The eastern part of the Black Sea and its tributaries are suitable habitats for several sturgeon species, among which Acipenser gueldenstaedtii , A. stellatus nudiventris persicus sturio H. huso well documented. However, different threats have led these species to a dramatic decline, all them currently listed as Critically Endangered some Locally Extinct in that area. We tested 94 wild samples from Rioni River by analyzing mitochondrial Control Region nuclear markers hybrid identification. data analyses (1) assessed diversity samples, (2) identified their (3) indicated instances hybridization. collected, besides confirming sharp decrease catches Beluga Stellate recent years, also revealed four juvenile hybrids between Russian sturgeon, providing first evidence natural interspecific hybridization Rioni. present communication raises concerns about status this area underlines urgent need conservation programs restore self-sustaining populations.