The impact of anthropogenic pressures on sturgeon migration in the Lower Danube

Abstract

Abstract The Black Sea sturgeons are anadromous fish species [1], which migrate upstream on the Danube River for breeding. The distance traveled in the migration process varies depending on each species, from tens to hundreds of kilometers [2]. After breeding, the anadromous sturgeons return to the Black Sea and go back to the Danube after a time that varies depending on the species between 3 and 5 years [3]. All sturgeon species that migrate in the Danube basin are on the IUCN Red List of Threatened Species [4]. Considering that sturgeon migration is a condition of the existence of species [5], INCDPM developed in 2011-2017 extensive research studies of their behavior. Using ultrasonic telemetry, unique information volumes have been obtained on the behavior during sturgeon migration in different hydrodynamic conditions and under the pressures caused by anthropogenic activities. The intensity of poaching was also analyzed, resulting in that this pressure represents a real threat to the existence of sturgeon species. Over 70% of the total specimens monitored in research studies, developed by INCDPM during the over 7 years of research, were poached. The research was conducted in Ml compliance with the provisions of the EU Biodiversity Strategy for 2030 [6], which aims to conserve endangered habitats and species, including by reducing and eliminating by-catches.