Effect of host species, sex, length, diet and different seasons on the parasitic infection of Tilapia fish in lake Manzalah

الملخص EN

Tilapia nilotica, Tilapia zilli, Tilapia galilaea and Clarias lazera were taken from Lake Manzalah to carry out this investigation.

A total number of 264 Tilapia fishes and 50 specimens of Clarias lazera (as a comparative group) were examined for parasitic infection.

The effect of some factors, on the incidence of the parasitic infection on the host fish is carried out.

I'he results of this study show that, 57.6% of the examined Tilapia fishes are infected with different types of parasites.

These parasites are: Protozoa (Trichodina), Monogenea (Dactylogyrus) Copepoda ( Lernaea and Ergasilus) and Acanthocephala ( Acanthosentis).

The prevalence of infection is highest in Tilapia zilli and lowest in Tilapia nilotica.

Female fishes are heavily parasitized than males.

The large sized fishes are more subjected to parasitic infection than smaller ones.

A definite seasonal effect is noted for the three Tilapia species under consideration.

Winter is found to be the season of severe parasitic infection of fishes, where the percentage of infection is obviously higher than the other seasons.

The lowest percentage of infection is recorded in summer.

The kind of food is a fairly factor in determining the type of helminth parasites which can be found in a fish.

Orientocreadium, a digenetic trematode is found in the intestine of Clarias lazera which is a carnivorous fish and of different mode of habits than Tilapia fishes.