Parasites of fish at Lake Tana, Ethiopia

Abstract

This study was conducted at Lake Tana Ethiopia, to identify parasites of fish from a total of 1766 fish of different species sampled during 1998–1999. The study showed that Contracaecum spp. were the most common larval nematode parasite that were identified from the mesentery of 52 (41.94%) Catfish (Clarias gariepinus), 17(24.64%) Barbus acutirostris, 102 (9.44%) Barbus tsanensis, 14(12.84%) Barbus brevicephalus, and from the pericardial cavity of 52 (59.8%) Nile tilapia (Oreochromis niloticus). The other larval nematodes identified from the mesentery included Amplicaecum spp. and Eustrongylides spp. Cuccullanus spp. (new geographic record) were recovered from the intestinal lumen of 2(0.19%) B. tsanensis. Among the digeneans, Clinostomum spp. were identified from the branchial cavity and skin of 50 (57.47%) and 4 (1.15%) O. niloticus, respectively. The Euclinostomum spp. were recovered from the kidney of 4 (4.6%) and branchial cavity of 2 (2.3%) O. niloticus. Mixed infection by Clinostomum spp. in their branchial cavity and Contracaecum spp. in the pericardial cavity was observed in 35 (40.23%) O. niloticus. Allocreadium sp. (new geographic record) was recovered from the intestinal lumen of 1 Barbus dainellii and Tetracotyle spp. (new geographic record) from the mesentery of 6 (50.0%) Barbus nedgia. Ligula intestinalis was the most prevalent cestode affecting 88 (8.14%) of B. tsanensis, 20 (40.0%) other small barbs and 32 (54.24%) of B. trispilopleura and it was considered as a significant pathogen. Proteocephalus spp. (new geographic record) was recovered from the intestinal lumen of 9 (0.83%) B. tsanensis. Among the crustaceans Dolops ranarum was recovered from the caudal fin of 1 C. gariepinus. The prevalence and pathogenic significance of the parasites as causes of diseases to fish related to the diverse fish fauna of the lake is discussed.


Key words/phrases: Cestodes, digeneans, fish parasites, Lake Tana, nematodes


SINET: Ethiop. J. Sci Vol.26(1) 2003: 31-36