Qualitative and quantitative changes in the ichtyofauna of the danubian reservoirs after the construction of the iron gates hydropower plant dams

• Main Authors: Lenhardt, Mirjana, Đikanović, Vesna, Hegediš, Aleksandar, Višnjić Jeftić, Željka, Skorić, Stefan, Smederevac-Lalić, Marija
• Format: Conference Object
• Language: unknown
• Published: Serbian Acad Sciences Arts, Belgrade 2018
• Subjects: Danube; human impact; ichthyology; management; pollution; Beluga; Beluga*
• Online Access: http://rimsi.imsi.bg.ac.rs/handle/123456789/1128; https://hdl.handle.net/21.15107/rcub_dais_10626

Human society reaps immense benefits from rivers and in the course of the last century man has considerably altered rivers, using them as waterways, for irrigation, energy production, water intakes, commercial and recreational fisheries, etc. As a consequence of anthropogenic effects, degradation of river courses has occurred and there is great need for preserving and restoring their physical, chemical and biological integrity. The Danube is an international river that connects 17 countries and has been under anthropogenic influence since ancient times. Intensive exploitation of fish in the early Holocene led to human settlements remaining for longer periods along the Danube. Numerous Neolithic archaeological sites demonstrate that fishing was the main economic activity of humans on the Danube. Alterations to the river's course in order to secure navigation through the Djerdap gorge were conducted already in the late 19th century, while significant changes in this part of the Danube occurred after the construction of the Iron Gate I and Iron Gate II dams, in 1970 and 1984, at Danube rkm 943 or rkm 863, respectively. This led to interruption of the Danube's longitudinal continuity and to the curtailment of migration routes of anadromous fish species that migrate from the Black Sea up the Danube for spawning. In the past, the beluga sturgeon (Huso huso) migrated all the way to Straubingin Germany (rkm 2327), and the Black Sea shad (Alosa immaculata) went as far as Budapest (rkm 1650). Overfishing and illegal fishing of sturgeon species for their highly prized caviar, water and sediment pollution, and physical alteration to the bottom and banks of the Danube, as well as the restriction of migration due to dam construction led to a significant decrease in population sizes of sturgeons and shads, which now have only 17.4 kilometers for spawning in the Serbian part of the Danube. At the same time, there was the introduction of non-native (allochthonous) fish species for aquaculture, which later became permanent ...