SUMMARY Seventy one heterotrophic bacterial isolates were obtained from Wuras Dam, phenotypically characterized and clustered with the unweighted-pair group method. Three groups were obtained of which the first contained 59 members in several clusters. Overall this group was characterized by a lack of positive characteristics (< 21%) e.g. a low fermentative ability. The second group contained three members exhibiting more positive characteristics (53%) and the third group nine members with 56,7% positive characteristics. Evaluations of the groups and clusters did not suggest any distinct spatial or temporal variations within the groups. Since the bacteria which were studied probably belong to the zymogenous group of Winogradsky (1949), attention should be paid to the presence of autochthonous and/or oligocarbophilic species in the impoundment.