LENGTH-WEIGHT RELATIONSHIPS AND FULTON CONDITION FACTOR (K) OF FRESHWATER FISH SPECIES FROM THE RUSCOVA RIVER, SPAWNING GROUND OF DANUBE SALMON HUCHO HUCHO, LINNAEUS, 1758 (PISCES: SALMONIDAE)

This study is the first reference regarding the length-weight relationships of freshwater fishes inhabiting one of the most important spawning waters of the endemic endangered Danube salmon (Hucho hucho). Fulton condition factor (K) was calculated for 1366 individuals belonging to 16 species from Ruscova River, north of Romania. Length-weight relationships were determined for 1362 specimens from 14 species. The smallest slope value (b) was determined for Romanogobio uranoscopus (b=2.2437) and the highest value for Telestes souffia (b=3.6058). The Danube salmon (Hucho hucho) showed positive allometric growth, having the calculated value of the slope of 3.3879. The mean values of Fulton condition factor (K) for the captured specimens were: Cottus gobio (1.161), Alburnus alburnus (0.3726), Alburnoides bipunctatus (0.8142), Barbus barbus (0.9434), Barbus carpathicus (0.9202), Chondrostoma nasus (0.8867), Romanogobio uranoscopus (0.8196), Phoxinus phoxinus (0.9888), Squalius cephalus (1.137), Telestes souffia (0.898), Barbatula barbatula ( 0.6693), Eudontomyzon danfordi (0.1293), Hucho hucho (0.8454) and Thymallus thymallus (0.9522).