ECOLOGICAL CHARACTERIZATION OF THE FISH COMMUNITIES WITHIN LOWER DANUBE RIVER

The main goal of the current study is to analyze the fish species of the Lower Danube River course in the context of river engineering projects that have modified the river bed and river shores and added structures which were necessary for flood protection, converting terrain to agriculture and maintaining the navigation lanes. In order to gain knowledge, the fish species were grouped into fish guilds. The Danubian fish are an important food source for the inhabitants of the Lower Danube River and their populations can act as a good indicator for human pressures, for instance for hydromorphological alterations. In the case of the Iron Gates II – Călărași (rkm 853 – 375), Călărași – Isaccea (rkm 375 – 100) and Danube Delta-Black Sea (rkm 100 – 0) sectors, a fair distribution of the rheophil A and rheophil B, eurytopic, stagnophil and anadromous fish guilds can be observed. The anadromous fish guild in not present upstream of the Iron Gates I in the Baziaș –Iron Gates I river sector (rkm 1075–943). The gobies are present in all sampled river sectors, including upstream of the Iron Gates. The results show no evidence of a shift in the ecological guilds during the intensive monitoring of the Călărași – Isaccea river sector with rheophil B and eurytopic being dominant. Further research is required in order to update the INCDPM Bucharest database and use the findings to consolidate upcoming policies regarding the implementation of measures meant to improve the conservation state of species and habitats