Prevalence and Densities of Contracaecum sp. Larvae in Liza abu (Heckel, 1843) from Different Iraqi Water Bodies

In monthly samples of Liza abu collected, June 2001-May 2002 from three localities (Hilla river, Al-Furat fish farm and Al- Mahaweel drain), Babylon province in the middle of Iraq. Fishes were infected with the third larval stage of the nematode Contracaecum sp. The infection of Contracaecum sp. larvae were analyzed according to the season, sex, host length, and sampling localities. Its prevalence and intensity was 11.9% and 1.1 larvae per fish respectively for the Winter, and the Summer had 47.6% and 3.5 larvae per fish respectively. The incidences were increased greatly during the Summer season, being higher in the females than the males for both the seasons of the year. There were slightly significant differences (p 0.01) between the infection of male and female fishes in the cases ofthe monthly variations of infection with Contracaecum sp. Infection with Contracaecum sp. larvae were positively correlated according to fish length, increased gradually in the larger fishes. Infection rates and mean intensity also varied with sampling stations (p 0.05).Generally, the changes in the percentage prevalence coincided with the changes in the mean intensity of infection.