Abstract
Various physical and biological factors influence the larval dispersal and connectivity of benthic species. Physical processes are the primary driver of larval transport, however biological processes have been found to play an important role as well. In this study, we developed and coupled a 2-D hydrodynamic model with an agent-based model to study Crassostrea virginica, oyster larval transport within the Charlotte Harbor estuarine system in southwest Florida. Freshwater flow entering into the southern region of the system, the Caloosahatchee River Estuary, is highly controlled by a series of lock and dams. As a result, considerable interannual variability exists in the amount of freshwater entering the Caloosahatchee River Estuary and this has been identified as a key stressor to the estuary’s oyster population. Oyster spawning in the estuary occurs throughout the wet season months (June-Oct.). Therefore, model simulations were performed during wet season periods of low, moderate, and high freshwater flow into the estuary to determine the impacts varying flows impose on larval transport and settlement in terms of success and connectivity between oyster reefs. The agent-based model was validated using oyster larval settlement data collected throughout a long-term, 2000-2016 study. The model was able to simulate settlement patterns during periods of low freshwater release which ultimately provided insight into the importance of the furthest upstream oyster reef as a larval source to the downstream reefs.
