Parasite communities of oreochromis niloticus baringoensis (Trewavas, 1983) in relation to selected water quality parameters in the hot springs of Lorwai swamp and Lake Baringo, Kenya

Abstract

Parasites are universal and are associated with many living organisms making them a vital component of any ecosystem. Fish parasites lead to a decline in market value of infected fish and may lead to mortalities in high intensities. Some parasites are zoonotic. Anthropogenic activities within the riparian and catchment areas of aquatic systems that lead to deterioration of water quality possibly increase the incidences of parasitic infections. Although fish parasites have been studied in lakes and ponds, parasites of fish found in swamps are rarely studied. This study aimed at evaluating the parasite communities of Oreochromis niloticus baringoensis in relation to selected water quality parameters in the two hot springs of Lorwai Swamp and Lake Baringo, Kenya. Using seine nets 347 fish were captured in July and August, 2018. They were transported alive to the laboratory at the Department of Biological Sciences, Egerton University, where they were killed by cervical dislocation and dissected after recording their lengths and weights. The fish were examined and parasites recovered, identified and quantified. Some of the recovered parasites were preserved in 4% formalin for identification and others in absolute ethanol for further genetic analysis. The parasite infection parameters were calculated using standard formulae. Selected physico-chemical parameters namely; Dissolved Oxygen (DO), temperature, pH, Electrical Conductivity (EC) and turbidity were measured in situ using appropriate meters. In addition, water samples were collected in triplicates from each sampling site for nutrient analysis. The correlation between the parasites prevalence and the selected water quality parameters were determined by Principal Component Analysis (PCA) using SPSS version 20. Results of the length-weight relationship indicated that the population in the hot springs had a good growth ratio while the mean Fulton‟s condition factor indicated that the population was in a very good condition and healthy despite the high water temperatures of up to 36.4 °C. Cichlidogyrus sclerosus and Clinostomum sp. were common in all sites and there were significant differences among the abundance (one-way ANOVA, F = 11.08, df (2, 9), p = 0.03), mean intensity (one-way ANOVA, F = 9.96, df (2, 9), p = 0.01) and prevalence (one-way ANOVA, F = 45.90, df (2, 9), p = 0.02) of the recovered parasites from the three sites. Amirthalingamia macracantha and Contracaecum sp. correlated positively with nitrogen compounds whereas Clinostomum sp. and Tylodelphys sp. correlated negatively with dissolved oxygen. In general, the study revealed that the parasitic infection parameters correlated with the water quality parameters and therefore measurable water pollution controls within the drainage basin should be put in place and the public should be sensitized on the importance of properly cooking the fish.