Current status of endemic mussels in the lower Ocmulgee and Altamaha rivers

Abstract

The Altamaha River Basin is well known among malacologists for its high percentage (ca. 40%) of endemic mussels. While little historical data exists to quantify changes in mussel abundance, many biologists believe that some species are declining. We assembled a large database of mussel occurrence records from surveys conducted since 1967 and used this data to assess the current status of endemic mussels in the lower Ocmulgee and Altamaha rivers. The percentage of sites occupied and the ranges of the Altamaha arcmussel, Altamaha spinymussel, and inflated floater have declined over the past 10 years. The remaining endemic mussel species occupy a large percentage of sites and appear to be stable. We recommend the development of a long-term monitoring program for Altamaha basin endemic mussels. Success of this program will require both probability-based sampling to estimate mussel density and detection probabilities along with qualitative sampling to document occurrences at new sites.