Prevalence, mean intensity and pathology of ectoparasite infections in nile tilapia (oreochromis niloticus) in aquaculture production systems in Morogoro urban and rural areas, Tanzania
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Date
2008
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Publisher
Sokoine University of Agriculture
Abstract
A cross sectional study was carried out between September 2007 to September 2008 in order to investigate the prevalence, mean intensities and pathology of ectoparasite infections on the gills and skin of Nile tilapia (Qreochromis niloticns) in selected ponds in urban and rural areas of Morogoro, Tanzania. Pond area, fish size and water quality were also determined. On-farm oral interviews using structured questionnaire were carried out on each farm involved in the study to establish management practices. Two types of ectoparasite namely: Trichodina species and Monogeneans were identified. Trichodina spp were more prevalent (P < 0.001) than Monogeneans. Gills
were the most affected organs than skins with a high number of parasites as well as pathological damage to the tissues (P < 0.001). Main pathological lesions observed on
the gills were hyperplasia, sloughing and necrosis of the lamellar epithelium, clubbing
and fusion of secondary lamellae. The physico-chemical parameters of water in the
ponds and management practices were different from one another in the study area;
however, there was no strong correlation between water quality and parasite
prevalence and mean intensities of the parasites. Prevalence and mean intensities of
parasites in fish varied in different ponds with some ponds having very high
prevalence and mean intensity and others with very low. This might be explained by
the different management systems based on the knowledge the farmers had on fish
husbandry and different weather conditions in the study area. There were significantly
higher parasite infections in fish in the urban than in the rural areas (P< 0.05). The
overall prevalence in the study area was 68% and on average the mean intensity was
5.3. The ectoparasites seem to pose a threat to the aquaculture industry in Morogoro
urban and rural areas as observed in this study. To rescue the situation, educational
intervention and further research on tilapia parasitic diseases is needed. Farmers have to be trained on proper husbandry and good management practices of fish farming. There is also a need for the government to promote aquaculture as the country has a great potential for it.
Description
Msc. Dissertation
Keywords
Nile tilapia, Qreochromis niloticns, Ectoparasite infections, Aquaculture production systems, Morogoro Urban, Rural areas