Edad y crecimiento de Barbus graellsi Steindachner, 1866, en el curso inferior del rio Ebro (NE España) (Pisces, Ciprinidae)

Abstract

This study deals with the age and growth of Barbus graellsi Steindachner, 1866. This species has been considered until now a subspecies of B. mendionalis Risso, and has been caught in the same watershed (Ebro) as well as the usual form (B. m. mendionalis). The specimens were caugth in the last 50 km of Ebro river, through nets and electrofishing. The age determination is carried out reading directly the scales by means of a microfilms reader. The oldest females found were 16 years old with a maximum of 474 mm while the oldest males were 11 years old with a maximum lenght of 338 mm. The relation between lenght and weight is more exponential in males than in females, thoug according to age, females reach a larger weight than males. The trends of the lineal and ponderal growth curves are similar in both sexes, but females grow more than males.