A Bayesian Approach for Estimating Mortality Rate of Oyster Mussel at Wallen Bend, Frost Ford and Swan Island, Clinch River

The oyster mussel (Epioblasma Capsaeformis) has declined 80% during the last several decades and is now listed as a federally endangered freshwater bivalve of United States. The restoration of the oyster mussel population is urgently needed. However, some vital rates, such as mortality rates, fertility rate and recruitment rate, are still poorly understood for this species, which may hamper the conservation of oyster mussel. In view of the observation inaccuracy in the age determination of mussels, we developed an age-length transition model to transit age frequency to length frequency depending on a stochastic von Bertalanffy growth model. A Bayesian statistical model was then developed to investigate population natural mortality rate at three sites in the Clinch River, Wallen Bend, Frost Ford and Swan Island, which represented the upper, middle and lower boundaries of the study reach. Three Bayesian diagnostic procedures were performed to evaluate convergence of the Markov Chains. Our results showed that the natural mortality rate varies over site. Considering the different population dynamics characteristics at different site, we suggested that the restoration of oyster mussel should be conducted properly based on different habitat.