Distribution and Utilization of Freshwater Oyster, Etheria Sp. (Bivalvia, Unioniforme, Etheriidae) in the Major Rivers of Northern Volta Basin of Ghana

Abstract

A survey was conducted to gather information on indigenous knowledge on the freshwater oyster (Etheria sp. Lam.1807), its distribution and utilization along the major rivers (i.e. Oti, the White Volta and Black Volta) forming the northern Volta Basin of Ghana. The occurrence of the oyster in the major rivers entering the Volta Lake indicates a widespread distribution of this mollusc in Ghana. The river Oti in the north-east serving as an international boundary between Ghana and Togo, the Black Volta on the north-west also serving as international boundary between Ghana and La Cotê d'Ivoire, and the White Volta running through the central portion, all harbor populations of the freshwater oyster. Etheria sp. has been a staple food for the inhabitants along the rivers where the oyster occur for many years. The oysters are collected from the riverbed mainly during the dry season, when the water level is low using locally manufactured implements like hoes, chisels and hammer. Biochemical analysis of the smoked meat from Nawuni, on White Volta, showed that it contained 40.7% protein, 27.4% carbohydrate, 8.6% fat, 3659 mg/100 g calcium and 2210 mg/100g phosphorus. Proximate biochemical composition on dry matter of the species compared favourably with other edible bivalves in West Africa. The freshwater oyster shells are currently, not being utilized for any known purpose in Northern Ghana, though marine oysters are utilised in livestock feed production. This paper serves as a baseline study on the freshwater oyster in northern Ghana, which has opened up more areas for further research.