Detailed analysis of beluga sturgeon (Huso huso) and stellate sturgeon (Acipenser stellatus) migration in the Lower Danube River

Abstract

The swimming ground speed and swimming depths of beluga sturgeon (Huso huso) and stellate sturgeon (Acipenser stellatus)were investigated using ultrasonic telemetry between 2011 and 2017 in the Lower Danube River (river kilometer (rkm) 0 Sulina–rkm1075 Baziaș). Acoustic telemetry receivers VR2W and V16TP tags (Vemco, Canada) were used to collect data about sturgeon migrationbehavior in the Lower Danube River between the Black Sea and the Iron Gate II dam. The tags, equipped with depth and temperaturesensors, provided data about beluga and stellate sturgeon migration periods, swimming speeds, and depths. Twenty-three belugasturgeon (184–245 cm TL) and twenty-one stellate sturgeon (92–135 cm TL) were ultrasonically tagged and passively tracked usinghydrophone receivers installed in the river between rkm 71 and rkm 860. Three tagged beluga sturgeon returned after 2 and 5 years andtwo stellate sturgeon returned after 2 years since the time of their initial release in the river. This study provides, for the first time, furtherdetails concerning beluga sturgeon and stellate sturgeon migratory behavior patterns, traveled distances, swimming depths, and theirswimming ground speeds during spawning migration.