Comparison of Parasite Prevalence in Marine Fish Sardinella maderensis (Teleostei: Clupeidae) According to Different Length and Fish Sex in the Waters Near the Coast of Benin, West Africa

Abstract

Aims: This study was designed to assess the diversity and the occurrence of parasites in Sardinella maderensis and the relationship between the prevalence of infestation and the fish length and sex. Place and Duration of Study: Fish samplings were realized in the Artisanal fishing port of Cotonou between November 2019 and March 2020. Methodology: During the study, 101 males and 64 females were sampled. They were kept on ice and transported into the laboratory. Each specimen was labeled and the length was mesure. Then, they were dissected to get the internal organs for endoparasites examination. After parasite identification and counting, the prevalence, mean abundance, and mean intensity were assessed. Ecological indices for parasite community analysis such as Shannon Wiener index, Piélou equitability index, and Jaccard’s Similarity index were determined. The chi-square test was performed to appreciate the probable significant variation between sex prevalence and length classes.  Results: A total of 742 individuals and eleven (11) species of the harvested parasites were distributed in five groups such as Monogenea, Digenea, Cestoda, Nematoda, and Copepoda. Nematoda were mostly represented in terms of number of recorded species and mean abundance. Total prevalence was 92.12%. No significant difference was recorded between prevalence in males and females (chi2 = 1.168; P = 0.279) on one hand and prevalence in fish length (chi2 = 2.41 ; P = 0.66). Cestoda exhibited a high prevalence while the high mean abundance was encounterd for nematoda. Nematoda has encountered 4 species whereas the two Trematoda were represented by only one species, each one. Ecological index record were representative of the equilibrium in parasite distribution between hosts sex. Conclusion: Parasitism in S. maderensis was characterized by an important fauna of parasites mainly represented by Nematoda and Digenea. The prevalence of parasites was not related to the host’s length or sex. These results, however, need further work to validate reliability.