Comparison of parasitic helminth infection between the different age groups of Clarias gariepinus from Asa dam Ilorin, north-central Nigeria

A total of 160 specimens of Clarias gariepinus comprising three age groups – juveniles (standard length 10.0 – 29.9 cm), sub-adults (fish length 30.0 – 39.9 cm) and adults (fish length 40.0 – 59.9 cm) were collected over a period of 8 months from Asa dam, a major river in Ilorin. The fish length and weight ranged from 12.5 to 41.0 cm and 152 to 597 g respectively. They were subjected to parasitological examinations. two cestode types - Amonotaenia sp and Polyonchobothrium clarias; two nematode types - Paracamallanus sp and Procamallanus laevionchus and one acanthocephalan – Neoechinorhynchus rutili were detected. Eighty-eight parasites were recovered. 27.5% of all fish examined showed parasitic infection. Helminth infection was found in juveniles and sub-adults only. Infection rate was higher in sub-adults than in juveniles