Prevalence of ecto-and endo-parasitic infections of farmed tilapia and catfish in Nyeri County, Kenya

Abstract

The objective of the present study was to determine the prevalence of fish parasites in farmed tilapia and catfish in Nyeri Central and Tetu sub-counties of Nyeri County, Kenya. A total of 366 live fish comprising of 89 (24.3%) catfish and 277 (75.7%) tilapia were caught using a seine net and purchased from 15 fish farmers between August 2014 and November 2015. One hundred and fifty eight (158/366; 43.2%) fish were from liner ponds while, 108/366 (56.8%) were from earthen ponds. Eyes, skins, gills, muscles, stomachs and intestines of the farmed fish were examined for parasites using dissecting and compound microscopes.

The results showed that 115 of the fish were infected with one species of ecto- or endo-parasite in the gills, skin, muscle, eye or gastro-intestinal tract, giving an overall prevalence of 31.4%. Parasitic infection rate was significantly higher (p < 0.05) in tilapia (67.8%; 78/115) relative to catfish (32.2%; 37/115) and there was no significant difference (p > 0.05) in fish parasite infestation rates between earthen (52.2%; 60/115) and liner (48.8%; 55/155) ponds. The prevalence of liner pond parasitic infection was relatively similar between catfish (56.4%; 31/55) and tilapia (43.6%; 24/55). However, in earthen ponds, there were significant differences (p<0.05) between catfish (10%; 6/60) and tilapia (90%; 54/60).

Nearly 15% (57/366) of fish examined had gill monogenean flukes (Dactylogyrus spp.), 8.2% (30/366) had metacercariae nodules of Clinostomum spp. in the muscles, 2.7% had leeches on the gills and 1.9% had Diplostomum spp. in the eyes. Other parasites identified were Trichodina spp. (1.4%), Acanthocephala spp. (0.8%),Contracaecum spp. (0.5%), Gyrodactylus spp. 0.5% and Paracamallanus spp. (0.5%), respectively. The parasites reported may affect thse health and quality of fish leading to condemnation at inspection