Prevalence and intensity of parasitic infestation on developmental stages of Clarias gariepinus reared in different water renewal culture systems

Abstract

Fish disease is a significant factor in aquaculture that causes negative impact. Therefore regular updates of epidemiological data must be ensured indicating the level of exposure to infections which prompted this study. 487 Clarias gariepinus comprising different developmental stages were collected from the water renewal systems; daily (DWR), weekly (WWR) and bi-weekly (BWR). The prevalence and mean intensity of infection were determined using standard parasitological methods. Water parameters were measured using recommended methods. Descriptive statistic (percentages and mean) was used for analysis. The parasites observed were protozoans - Trichodina spp., Vorticella spp., Tetrahymena spp Chilodonella spp., Ichthyobodo spp., Piscinoodinium spp., and Ambiphyra spp.; monogenean trematodes - Dactylogyrus spp., Gyrodactylus spp., and suspected Salmonichus spp.; crustacean parasites – Argulus spp. and unidentified Nematode. The highest prevalence and intensity of 80% and 55.50 ± 18.63 respectively were recorded in Trichodina spp infection in fingerlings, under the BWR. With Trichodina spp and Dactylogyrus spp prevalence of 80% and 40% on the gills respectively and 60% prevalence of Trichodina spp on the skin, the gills and the skin are the most preferred predilection sites for Trichodina spp, while Dactylogyrus spp has the gills as its main predilection site. The rate of single infection was higher than co-infection in all the culture systems for all developmental stages of C. gariepinus.