Romanogobio uranoscopus (Agassiz, 1828)
Gobio uranoscopus (Agassiz, 1828): Drensky, 1951: 84; Karapetkova, Zivkov, 1995: 118.
Conservation status: in Bulgaria: Endangered EN [A1a+3; B1b+2b], BDA-II; International: IUCN [DD], BeC-III, HD-II.
General distribution. In the basins of the rivers Danube and Vardar and in some Greek rivers (the Aliakmon and the Pinios). It is found mainly in the eastern part of the Danube basin: in the middle and upper reaches of its tributaries. Its finding is reported in Bulgaria, Romania, Slovenia, Serbia and Hungary. Single speciemens are caught in Austria and Slovakia.
Distribution and abundance in Bulgaria. It is found only in the Danube tributaries. Initially, it was recorded in the Iskar River near Sofia , and later, in the rivers Ogosta, Beli Vit, Cherni Vit, Osam and Yantra [2, 3, 4]. The species was also recorded in the Alexander Stamboliyski Reservoir , immidiatly after its damming, as well as in the rivers Vidima, Rositsa and Yantra . In the last 20 years, it has been found in the rivers Vit and Palakariya [7, 8], as well as in the rivers Skat, Lom, and the upper reaches of the rivers Negovanka and Belitsa (the Yantra River basin) [our data].
Habitats. It inhabits only the upper reaches of permanent rivers with swift current, cold water and sandy or gravelly bottom.
Biology. Poorly known. A typical reophilic species. Spawning takes place in shallow water with rapid currents. The age of sexual maturity is not known. It feeds on benthic invertebrates and diatoms. The life span is up to 6 years .
Similar species. The gudgeon (Gobio gobio), the white-finned gudgeon (Romanogobio albipinnatus) and the Kessler's gudgeon (R. kesslerii), from which it is differentiated by the darker colour, longer snout and the interrupted medially lower lip.
Negative factors. Fluctuations in river discharge as a result of river regulation activities; deforestation (especially in the mountain regions); water pollution.
Conservation measures taken. The species was included in Annex II of the Biological Diversity Act (2002).
Conservation measures needed. Restriction on the regulation activities and micro-hydro power development in the upper reaches of the Danube tributaries; control of deforestation in the mountain regions; protection of the rivers against pollution.
References. 1. Drensky, 1921; 2. Chichkoff, 1937; 3. Chichkoff, 1939; 4. Drensky, 1951; 5. Dimitrov, 1957; 6. Karapetkova, 1972; 7. Dikov et al., 1988; 8. Dikov et al., 1994; 9. Banarescu et al., 1999.
Authors: Tihomir Stefanov, Teodora Trichkova