Food and feeding habits of the catfish, Bagrus docmak (Forsskal, 1775) (Pisces:Bagridae) in Lake Chamo, Ethiopia

Abstract

The natural food of the catfish Bagrus docmak was studied from February 1995 to February 1996 in Lake Chamo, Ethiopia. The stomach contents of a total of 534 fish samples, ranging in size from 33—99 cm fork length (LF) and 500—17400 g in total weight (WT) were investigated. The diet of B. docmak was composed of insects (larvae, nymphs and adults), aquatic snails and different fish species such as Synodontis schall, Labeo horie, Oreochromis niloticus, Barbus sp. and Hydrocynus forskalii. Juvenile B. docmak (< 40 cm LF) ingested more insects than fish while older fish were largely piscivorous, with fish constituting more than 98% of their diet by weight. S. schall was the most important prey and occurred in more than 81% of all the stomachs of large B. docmak. The prey:predator (S. schall:B. docmak) length ratio varied between 1:2 and 1:6. The feeding habit of B. docmak in Lake Chamo is compared with that of other tropical African lakes that have similar ichthyofauna.

SINET: Ethiopian Journal of Science Volume 24, No. 2 (December 2001), pp. 239-254



Key words/phrases: Bagrus docmak, Ethiopia, Lake Chamo, prey:predator ratio, Synodontis schall