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

Tamar Beridze,Leonardo Congiu,Elisa Boscari,Tamari Edisherashvili,Fleur Scheele,Cort Anderson

doi:10.1007/s10592-021-01413-7

Tamar Beridze, Leonardo Congiu + Show 4 more

Open Access

https://doi.org/10.1007/s10592-021-01413-7

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Abstract

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

Highlights

Sturgeons are among the most endangered species groups in the world according to the International Union for Conservation of Nature (IUCN 2010), with some of the mostTamar Beridze, Elisa Boscari have contributed to this work.The population decline is mainly caused by habitat degradation, including river damming and consequent high sediment flushing, overfishing, and pollution
Conservation Genetics spawning river of the Eastern Black Sea. This was confirmed by monitoring research on sturgeon recruitment in the Rioni conducted by Fauna & Flora International (FFI) between 2018 and 2020
The collected data has unexpectedly indicated the occurrence of interspecific hybrids between two species of sturgeon historically known to reproduce in the Rioni River

Summary

Introduction

Sturgeons are among the most endangered species groups in the world according to the International Union for Conservation of Nature (IUCN 2010), with some of the mostTamar Beridze, Elisa Boscari have contributed to this work.The population decline is mainly caused by habitat degradation, including river damming and consequent high sediment flushing, overfishing, and pollution. Keywords Sturgeons · Interspecific hybrids · Acipenser gueldenstaedtii · Acipenser stellatus · Rioni · Black Sea

Results

Conclusion