Prevalence of monogenea trematodes in different developmental stages of <i>Clarias gariepinus</i> in Delta State, Nigeria

Abstract

Monogenea trematodes are ectoparasitic worms of numerous species including the two super – genera (Dactylogyrus and Gyrodactylus). They infect freshwater organisms, primarily fishes. They are harmless at low infestation, but heavy infestations cause wounds and gills hypertrophy which compromises respiratory functions. Out of 231 fish examined in this study, a total of 72 specimens were infected with an overall prevalence of monogenea trematodes infections of 31.17%. Dactylogyrus sp. was recorded in juveniles, post juveniles, and adults with a total prevalence of 23.6%. No Dactylogyrus sp. was found in fry and fingerlings. The total prevalence of 76.39% was recorded for Gyrodactylus sp across all stages. Gyrodactylus sp. infected the gills of all the stages in different frequencies, juvenile recorded the highest and fry the least. Dactylogyrus sp were found more on the skin of adult Clarias gariepinus than the gill. The water quality parameters recorded were pH, dissolved oxygen, ammonia, water and atmospheric temperatures.