Spawning period and sexual maturity of the fishes Scardinius erythrophthalmus Linnaeus, 1758 and Rutilus rubilio Bonaparte, 1837 in the reservoir of Sidi-Salem (NW Tunisia)

IMED DJEMALI^1*, AMOR EL ABED¹ and OTHMAN JARBOUI²

1 National Institute of Sciences and Technologies of the Sea, 28 rue du 2 Mars 1934, Salammboω, 2025 Tunis, Tunisia
2 National Institute of Sciences and Technologies of the Sea, Sfax, 3018 Sfax, Tunisia

Abstract

Overall 1447 specimens of Rutilus rubilio and Scardinius erythrophthalmus were collected in the reserve of Sidi-Salem dam (NW Tunisia) for the determination of the spawning period based on the monthly variations of the gonadosomatic index, hepatosomatic index and the condition factor (K). Samples were collected from January to December 2001. The results showed that the spawning period of R. rubilio ranges from March to April, whereas that of S. erythrophthalmus from April to September. The size (total length) at first sexual maturity (L₅₀), was assessed based on the logistic function and was 7.8 ± 0.23 cm (females) and 8.5 ± 0.43 cm (males) for R. rubilio and 7.9 ± 0.49 cm (females) and 8.5 ± 0.19 cm (males) for S. erythrophthalmus, respectively.