Prevalence Of Nematode Contracaecum And Cestode Ligula Intestinalis Parasites Infection In Two Fish Species At Lake Tana

A cross sectional study was conducted from November 2011-April 2012 in two species of fish from Southern Gulf of Lake Tana to determine the prevalence of Contracaecum and Ligula intestinalis parasite infecting fish. A total of 400 fish comprising of 200 49.5 Tilapia nilotica Oreochromis niloticus were caught by gill nets of variable size and 200 22.5 small barbus were caught by the help of scup net. Of all fish examined 161 40.25 were found to harbor Contracecum helminth parasite on both fish species. A significantly higher infection was found in Tilapia nilotica fish species p0.05. There was no significance variation p0.05 revealed in the occurrence infections between different size categories in both fish species but there was a tendency of increasing infection with body length in large Tilapia nilotica. The study demonstrated that Contracecum from pericardial cavity was the most prevalent nematode with prevalence of 49.5 and 31 in Tilapia nilotica and small barbus respectively. Ligula intestinalis was detected only in small barbus fish species and the prevalence is 22.5. 8 4.97 small barbus fish were found to harbor both Ligula intestinalis and Contracaecum helminthes parasite. Even though no statistical significance difference were observed between the two sex groups in each fish species 64 39.75 males and 8955.28 female were infected by Contracecum parasites. From results of the study it was concluded that the parasite was found either free and or encysted in the pericardial cavity. On average of 4 larvae of Contracecum and a maximum of 3 worms of Ligula intestinalis per fish were collected. The observed infection rates are predominantly related on the distribution of piscivorours birds which are more abundant in area where there are high fishing activities and increase number of discarded filleted wastes.