Study of some ecological parameters in nematode parasites of freshwater fish in the Senegal and Gambia rivers

Abstract

This study was conducted in the rivers of Senegal and the Gambia over three consecutive years, during both dry and wet periods. A total of 1216 fish were sampled during this period, with 551 from Gambia and 665 from Senegal. The fish were classified into 29 species. Chrysichthys mauris Valenciennes, 1840 is the host fish with the broadest spectrum of parasites, with ProCamallanus and Contracaecum being the most common genera of nematodes. Chrysichthys mauris Valenciennes, 1840, Clarias gariepinus Burchell, 1822, Synodontis annectens Boulenger, 1911, and Synodontis nigrita Cuvier et Valenciennes, 1840 exhibit the highest biodiversity indices, which vary depending on the seasons and sex of the fish. The overall prevalence of fish parasites varies by locality and sex. Only Citharinus citharus Geoffroy Saint-Hilaire, 1809 shows significant differences in weight and size, with respective values of 6.3e-08 and 0.01653.