SPECIES COMPOSITION AND ABUNDANCE OF FRESHWATER FISHES FROM THE LOWER REACHES OF THE WHITE VOLTA AT YAPEI, GHANA

Abstract

A study to assess the fish species composition and abundance was conducted over a six month period covering the post flood and dry seasons in the lower reaches of the White Volta River at Yapei, Ghana. Data was taken from fish landings at three main landing sites. Species were sorted and identified according to standard identification keys for the fresh and brackish water fishes of West Africa. Abundance was calculated as weight of a species/weight of total catch 100. Fifty two (52) species belonging to sixteen (16) families were encountered during this six months period of study. Alestes baremoze was the most abundant species. It made up 80.6kg of the total of 462kg of fish caught during the period of study, and thus representing 17.5%. It was followed by Brycinus leuciscus (58.3kg, representing 12.6%) and Brycinus nurse (27.6 kg, representing 6.0 %). All the three top species were semi pelagic omnivorous fish belonging to the family Alestidae which was also the most abundant family in all the landing sites. Alestidae which is a family of six species made up 42.2% of all catches. Synodontis eupterus was the least abundant species. Throughout the period of study, only 0.02kg of Synodontis eupterus was encountered and measured. The family Tetraodontidae which has a single genus; Tetraodon, represented in West African fresh and brackish waters was the least abundant.