Open AccessEvaluating the Effect of the Hydrotechnical Works from the Danube’s Caleia Branch on the Spawning Migration of Sturgeons
Author(s) -
Tiberius-Marcel Danalache,
György Deák,
Elena Holban,
Marius Raischi,
Diana Simona Fronescu,
Cristian Andi Nicolae,
Mihai-Alexandru Cristea
Publication year - 2020
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/616/1/012025
Subject(s) - sill , spawn (biology) , fish migration , sturgeon , surge , hydrology (agriculture) , fishery , environmental science , oceanography , geology , geomorphology , geotechnical engineering , biology , geochemistry , fish <actinopterygii>
Over the years, to maintain navigation along the Danube, the implementation of a series of hydrotechnical works was imposed in order to ensure the continuity of economic activities. Between 2011 and 2014, one such project was built in the vicinity of the county of Braila, on a secondary branch of the Danube - The Caleia branch. The main goal was to redistribute water discharge from the secondary channel to the main branch by construction of a bottom sill. The bottom sill and subsequent discharge redistribution led to hydrodynamic alterations caused by increased water current velocities. These modifications of the hydrodynamic regime may affect the migration of anadromous sturgeon species that swim from the Black Sea to spawn upstream, therefore making the monitoring of the impact paramount. Considering the fact that the anadromous migrating species are internationally protected species, by a series of agreements and conventions, and that the stocks of the species are still in decline, a complex monitoring program was implemented in the affected area. This study presents important information regarding the site utilization during spawning migration and an evaluation of the behavior of sturgeons tagged with ultrasonic transmitters that migrated upstream over the bottom sill. During the monitoring period, the studies show that five sturgeons passed the bottom sill during their upstream migration, swimming against maximum water current velocities of 2.5 m/s.