Scaridae fish species including Scarus psittacus, S. frenatus, S. genazonatus, S. fuscopurpureus and S. niger, were collected from Red Sea in Egypt. The DNA fingerprints of these species were identified using RAPD-PCR technique with eight decamer primers. A total of 93 bands were scored in all species using the selected primers, with the size range varying from 190 to 2500 bp. On average, each primer amplified 11.63 bands per species. Each species had both monomorphic and polymorphic DNA bands. The polymorphic bands represent 34.41% in all fish species. The highest similarity index (70%) was found between Scarus psittacus and S. frenatus, while the lowest one (51%) was between Scarus psittacus and S. niger, S. genazonatus and S. fuscopurpureus and S. genazonatus and S. niger. Therefore the phylogenetic relationships among the five studied scaridae species were clearly resolved in dendrogram, they were clustered into four clusters groups: the first one comprised, S. fuscopurpureus and S. niger, the second included S. psittacus, S. frenatus and S. genazonatus, the third included S. genazonatus and the fourth branch contained S. psittacus and S. frenatus. In conclusion, the obtained results exhibited that the five Scarus species are distinctive ones. In addation, the RAPD patterns are suitable tools to differentiate between fish species.

Oreochromis niloticus and Tilapia zilli are important sources of protein food for the Egyptians. It provides about 70% of the total fish production in Egypt (EI-Zarka, 1961). Digenetic trematodes and their metacercariae take a great interest as they were one of the most widely distributed parasites infecting fish causing low weight gain, high mortality and some of them may have zoonotic importance (Hernandez et al., 1998). Biotic factors as parasite life cycles and fish age/size and abiotic factors such as water temperature, current and/or depth also affect the distribution of parasites which may be aggregated or over dispersed in the host (Iyaji and Amana, 2015). Ramadan (1991) reported that the host species affect the rate of infection. He recorded the rate of infection in T. nilotca, T .zilli and T. galilaea fish in Lake Manzala. The highest rate of infection was found in T. zilli while, the lowest rate of infection was found in T. nilotica.

No abstract