New biological data on the brown ray, Raja miraletus (Chondrichthyes: Rajidae), off the coast of Senegal (eastern tropical Atlantic)

Abstract

A total of 483 specimens (236 males and 247 females) of the brown ray Raja miraletus were collected off the coast of Senegal (eastern tropical Atlantic). The hepatosomatic index (HSI) and gonadosomatic index (GSI) were calculated in both males and females, and the oviducosomatic index (OSI) in females. Both HSI and GSI increased significantly with specimen size and the three maturity stages considered (juveniles, subadults, and adults). The monthly HSI of adult males did not show significant variations throughout the year. In contrast, the HSI of adult females, GSI of both adult males and females, and OSI of females showed significant variations throughout year. This suggests that monthly variations occurred in the production of gonadal products even though vitellogenetic activity was observed throughout the year.

Keywords

• Chondrichthyes
• Rajidae
• Raja miraletus
• liver
• gonads
• oviducal glands