Status of the Mussel Fauna of the Poteau River and Implications for Commercial Harvest

—The Poteau River, a major tributary of the Arkansas River, flows through the Ouachita Uplands of eastern Oklahoma and western Arkansas. The river has been harvested for mussels, historically by the Caddo Indians and recently for the pearl industry. We documented the current distribution and abundance of mussels in the river, compared this with historical distributions and examined whether the river can sustain current levels of commercial harvest. The Poteau River retains a rich mussel fauna of 35 species. However, mussel abundance is much lower than in surrounding rivers. Mean total mussel densities in the largest beds in the river are 3.8 individuals/m. Densities of the two commercially harvested species, Megalonaias nervosa (washboard) and Amblema plicata (threeridge), are only 0.15 and 1.25 individuals/m, respectively. Mussel size distributions indicate very low recent recruitment of both M. nervosa and A. plicata. The majority of M. nervosa exceed the shell height limit of 4 inches established by the state of Oklahoma and, thus, are not protected by this regulation. Our data indicate that the Poteau River cannot sustain commercial mussel harvest. A recently established mussel sanctuary should be retained and further commercial harvest of mussels should be avoided.