Incidence of parasitic infestation on the skin and gills of Clarias gariepinus (Burchell) reared under different culture systems
A total of 140 fish samples of Clarias gariepinus comprising of 20 fry from two hatcheries, 60 fingerlings and 60 adults reared under the water recirculating, water flow-through and the earthen pond culture systems, were clinically examined for presence of ecto-parasites on the skin and the gills. The ectoparasitic fauna observed comprises of 3 protozoans including Trichodina sp, Costia sp and Epistilis sp, and 4 metazoans of which 3 are monogenetic trematodes including Gyrodactylus sp, Dactylogyrus sp and Cleidodiscus sp. The fourth metazoan is a leech; Piscicola sp. Infestation due to Trichodina sp and the monogenetic trematodes were observed in all developmental stages of C. gariepinus and under all the culture systems studied. The highest incidence rate of 100% Trichodina sp infestation was observed on both the skin and the gills of the fingerling stage. The highest parasitic load of 10 organisms per field was also observed on the skin of the fingerlings reared in the earthen pond. Infestation due to monogenetic trematodes was observed to be highest (70%) on the skin of fingerlings reared under the water flow through system, while in the earthen pond system, the incidence rate of 60% was observed for both the fingerlings and the adult fish. Costia sp was observed in all the 3 culture, s;ystems, with the highest incidence of 50% and parasitic load of 2. 5 organisms per field recorded on both the fry and the skin of the fingerlings reared in earthen pond. The incidence of Epistilis sp infestation on the gills of catfish fingerlings reared in the water recirculating system was observed to be low (5%), while Piscicola sp infestation was observed only on the skin of adult C. gariepinus at an incidence rate of 35%, but with a high worm burden of 15 organisms per fish. The fingerlings seem to be more susceptible to Trichodina sp and the monogenetic trematodes, especially under the earthen pond culture system. Catfish hatcheries, especially those producing fingerlings in the earthen ponds must ensure adequate and efficient hygiene practices. They may also need to disinfect their stock appropriately at harvest, prior to distribution to farmers to avoid spread of para sites.
| Main Authors: | , , |
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| Format: | conference_item biblioteca |
| Language: | English |
| Published: |
FISON
2012
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| Subjects: | Aquaculture, Clarias gariepinus, Heterobranchus longifilis, Heterobranchus bidorsalis, Nigeria, freshwater environment, Fish, Parasites, Infestation, Skin, Gills, Fish culture, Recirculating systems, Fish ponds, Fingerlings, |
| Online Access: | http://hdl.handle.net/1834/38785 |
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| Summary: | A total of 140 fish samples of Clarias gariepinus comprising of 20 fry from two hatcheries, 60 fingerlings and 60 adults reared under the water recirculating, water flow-through and the earthen pond culture systems, were clinically examined for presence of ecto-parasites on the skin and the gills. The ectoparasitic fauna observed comprises of 3 protozoans including Trichodina sp, Costia sp and Epistilis sp, and 4 metazoans of which 3 are monogenetic trematodes including Gyrodactylus sp, Dactylogyrus sp and Cleidodiscus sp. The fourth metazoan is a leech; Piscicola sp. Infestation due to Trichodina sp and the monogenetic trematodes were observed in all developmental stages of C. gariepinus and under all the culture systems studied. The highest incidence rate of 100% Trichodina sp infestation was observed on both the skin and the gills of the fingerling stage. The highest parasitic load of 10 organisms per field was also observed on the skin of the fingerlings reared in the earthen pond. Infestation due to monogenetic trematodes was observed to be highest (70%) on the skin of fingerlings reared under the water flow through system, while in the earthen pond system, the incidence rate of 60% was observed for both the fingerlings and the adult fish. Costia sp was observed in all the 3 culture, s;ystems, with the highest incidence of 50% and parasitic load of 2. 5 organisms per field recorded on both the fry and the skin of the fingerlings reared in earthen pond. The incidence of Epistilis sp infestation on the gills of catfish fingerlings reared in the water recirculating system was observed to be low (5%), while Piscicola sp infestation was observed only on the skin of adult C. gariepinus at an incidence rate of 35%, but with a high worm burden of 15 organisms per fish. The fingerlings seem to be more susceptible to Trichodina sp and the monogenetic trematodes, especially under the earthen pond culture system. Catfish hatcheries, especially those producing fingerlings in the earthen ponds must ensure adequate and efficient hygiene practices. They may also need to disinfect their stock appropriately at harvest, prior to distribution to farmers to avoid spread of para sites. |
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