Abdul Amer R. Jassim - Marine Science Center, University of Basrah
Nadra K. Al-Salim - Marine Science Center, University of Basrah
Najim R. Khamees - Department of Fisheries and Marine Resources, College of Agriculture, University of Basrah

Objective: Parasitic diseases cause great losses in fish aquaculture where it considered a mean health problem therefore the present study aimed to recognize the parasitic fauna of grass carp and its source & transmission methods. The study refers to presence of a parasitic nematode i.e., as new record in Iraqi waters. Method & Materials: Nematoda is collected from the intestine of 110 samples of grass carp fishes that collected from three stations in Basrah during the period from March till July 2007. The first station was Basrah University (Experimental Aquaculture Station). The second station was Al-Mudeina station, Located in Al-Midaina Shire and the third station was Faddak station, located in Shat-Alarab Shire. Nematoda was isolated and killed by warm water (60-63 c°). The samples was saved in alcohol-cliciren and after that prepared temporary slides by using lacto phenol and semi permanent by cleciren gel (Garcia and Ash 1979). Results & Conclusion: Cultured grass carp was found infected by the nematodes Pseudocapillara tomentosa . Fishes of Fadak fish station (Basrah,IRAQ) were the only hosts of such parasites in this study. The infection was reported during the period from april till July 2007.The highest percentage of incidence of infection was 88.8% during April, then it dropped to 5.8% during July. This is the first record of P. tomentosa in Iraq and the Middle East. These helminthes did not infect grass carp in other studied fish stations, on other hand, the infected grass carp were fed on aquatic plants which were brought directly from the natural water bodies. Such plants may harboring the infective stages of the parasites. The nematodes infected the outer layers of the intestine (i.e. the mucosa layer) and heavy mucus was noticed in the site of infection. The intestine was emaciated in the site of infection. Females and males of P. tomentosa were both occurred in the infected fish, the males were shorter and thinner than the female parasites. The mean total length of the female nematodes was 5.2 mm. while only 2.5 mm. for the male parasites.

nematode, Capillariidae, Pseudocapillaria tomentosa, grass carp, fish pond