INNOVATIVE BY-PASS SOLUTION FOR IRON GATES I TO RECONNECT THE HISTORICAL MIGRATION ROUTES OF WILD ANADROMOUS STURGEON SPECIES, IN ORDER TO IMPROVE THEIR CONSERVATION STATUS

The anadromous sturgeon species in the lower Danube are currently critically endangered and based on the studies of the INCDPM expert team and the 2022 report of IUCN-SSG (Sturgeon Specialist Group) it appears that the future prospects of these populations are unfavourable. This situation occurs mainly as a result of anthropogenic impacts, especially due to intensive fishing, poaching and hydrotechnical constructions (e.g.: dams, immersed obstacles such as the bottom sill on Bala Branch). The dams interrupted the historical spawning migration routes of these species and the bottom sill can interrupt them in the future. In this context, INCDPM has elaborated an innovative by pass solution for the Iron Gates I, based on the longterm monitoring of ultrasonically tagged sturgeons from the Black Sea to the Iron Gates. This article presents the methodology developed by INCDPM in order to ensure the implementation of the innovative by-pass solution with minimal risk of unseccesful restoration of the historical migration routes. The study aims to present the specific migration conditions and the actual routes, which have been determined by over a decade of in-situ monitoring of ultrasonically tagged specimens. Additionally, simulations of upstream migration will be conducted and GIS maps will be developed to present historical migratory routes, with consideration given to hydrodynamic conditions and climate change scenarios.