Assessing Habitat Suitability of Ribbed Mussels (Geukensia Demissa) in Georgia Salt Marshes by Examining Predicted Mussel Densities and Mussel Population Parameters

Geukensia demissa (ribbed mussel) is an ecology important bivalve that has the potential to contribute to salt marsh restoration. Understanding the factors that contribute to the distribution of mussels can help inform managers on choosing locations to optimize the survivorship of mussels in restoration projects. This study sought to model mussel densities across the coast of Georgia and to compare predicted mussel densities with mussel population parameters as means to gauge habitat suitability. Mussel densities were collected through field surveys across a range of salt marshes along the coast of Georgia and were compared with spatial data such as distance to creek heads (the ends of intertidal creeks which flood the marsh platform), elevation, and slope. Highest predicted mussel densities occurred at an elevation of 0.7m relative to NAVD 88, close to creek heads and far from subtidal creeks. Using the predicted mussel densities from the model, low, medium and high density mussel sites were selected at two geographic locations, Cannon’s Point Preserve, St. Simons, Georgia and Dean Creak, Sapelo Island, Georgia, to conduct mussel growth, predation, and recruitment experiments. In areas with higher predicted mussel densities, mussel recruitment and growth rates were the highest. Despite being statistically significant, differences in growth rates may not be biologically meaningful. While not statistically significant, predation risk was lowest in areas of high predicted mussel densities and increased with decreasing density. This indicates that in areas of low predicted mussel densities, recruitment and predation risk are likely the limiting factor to mussel densities