Monday, June 4, 2007 - 1:30 PM
24

An Evaluation of Estimators of Mussel Abundance in a Large Lowland River in the Southeastern United States

Jason R. Meador and James T. Peterson. Georgia Cooperative Fish and Wildlife Research Unit, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602

Accurate population estimates are crucial for the development and facilitation of effective freshwater mussel conservation strategies. Mark-recapture designs are commonly used to estimate population parameters, but design-specific assumptions must be met to obtain reliable estimates. We evaluated the efficacy of various sampling designs and estimators for estimating the abundance of three mussel species in the Altamaha River in Georgia. We found count based indices were substantially biased by incomplete detection and temporary emigration into the substrate. Temporary emigration also affected estimates from traditional mark recapture designs. Pollock’s robust design, which allows for relaxation for certain assumptions, was found to be the best estimator.  Our results emphasize the importance for estimating detection and emigration of mussels rather than relying solely on raw count data or traditional capture recapture methods. We also believe that this design is well suited for freshwater mussels not specific to the Altamaha River, and encourage implementation of the design in other systems.