The objetive of this study was to investigate the relationships between fish condition and environmental variables in populations of Sclater’s barbel (Barbus sclateri) from semi-arid reservoirs in the south-eastern Iberian Peninsula. These artificial ecosystems are characterised by waters of greater salinity. Weight-length relationship was used to test differences in fish condition between 6 populations of Sclater’s barbell from reservoirs with different environmental parameters. Significant differences in fish condition among populations studied (ANCOVA, p < 0.05) were found. The condition of Sclater’s barbel was dependent on ecological variables related mainly to water quality and, consequently, with the substrate and management of the basin. Water conductivity was the variable which affected in the most significant way the fish condition. In conclusion, salinization and high water conductivity of reservoirs could have a negative effect on fish condition. These effects should be considered when such populations are subjected to sports fishing regulations, recovery programmes or any other management programme. | El objetivo del presente trabajo fue analizar la relación entre la condición de los individuos y las variables ambientales en poblaciones de Barbus sclateri de embalses localizados en una zona semiárida del sureste de la Península Ibérica. Estos ecosistemas artificiales están caracterizados por una alta salinidad de sus aguas. Las relaciones Peso-Longitud de los individuos fueron utilizadas para la determinación de diferencias en la condición entre 6 poblaciones de Barbus sclateri de embalses con diferentes parámetros ambientales. Fueron obtenidas diferencias significativas en la condición entre las poblaciones estudiadas (ANCOVA, p