Preliminary data of life history traits of Mormyridae (Actinopterygii: Teleostei) in the Upper Sanaga River, Central Region of Cameroon

Abstract

The present study on some biological aspects of the Mormyridae fishes, was conducted between May and August 2015 in the Upper Sanaga at Lékié Department (Monatélé Town), Center Cameroon. For this purpose, 125 specimens collected by local fishermen were used. Fishes were identified and measured, and their feeding and reproductive parameters were obtained after dissection. The catch composition of 4 species (Campylomormyrus phantasticus, Mormyrops anguilloides, Mormyrus macrophtalamus, Mormyrus tapirus) of Mormyridae identified in the region was very low (17%–30%). The mean ± standard deviation of total weight and total length were 103.14 ± 37.83 g and 27.47 ± 4.84 cm, respectively. The minimum and maximum size (of 21.1 cm and 43 cm) were recorded from C. phantasticus and M. anguilloides, respectively. The mean ± standard deviation of the relative length and mass of the digestive tract were 0.35% ± 0.20% and 5.27% ± 23.20%, respectively confirming that Mormyridae fish species have a strict carnivorous diet and consume prey that are difficult to digest. The size frequency distribution of the Mormyridae fishes showed that the majority of the fish caught are small sizes in classes 23–26 cm and 26–29 cm in C. phantasticus, M. macrophthalamus and M. tapirus. M. anguilloides did not record small specimens, however, it recorded larger sized specimens (41–44 cm) compared to the rest. The sex ratio ranged from 1M: 1.14F (M. anguilloides) to 1M: 4F (M. tapirus), mean 1M: 2.04F has been generally in favour of females. The gonadosomatic index (GSI) was generally low in all species. However, it was higher in females of C. phantasticus and M. anguilloides compared to other species. The hepatosomatic index (HSI) was weakly correlated with the GSI in these species.

Keywords

• Mormyridae
• Endogenous species
• Reproduction
• Tropical river