Meeting Abstract
The 2008 Indian River Lagoon Comprehensive Conservation and Management Plan and Canaveral National Seashore’s Water Resources Management Plan (2001) express concerns about the negative impacts of recreational boating activity in the Indian River Lagoon (IRL), and more specifically the northernmost part of the IRL, Mosquito Lagoon (ML). Our research is focused on the direct impacts of boat wakes on intertidal reefs formed by the eastern oyster Crassostrea virginica. There has been a 24% loss of oyster habitat in ML since 1943, where natural oyster reefs have been replaced by dead reefs which do not serve the same ecological function. All dead oyster reefs were found adjacent to channels with boating activity which were too narrow to generate significant wind-driven wave action. However, no studies to date have confirmed dead reefs can be a direct result of boat wakes. Therefore, we addressed the following questions in ML: “What wake heights and intensities do different boat types generate that contact intertidal oyster reefs?,” and “What amount of sediment erosion, dislodgment, and oyster movement do these boat wakes generate?” A series of boat pass experiments in ML addressed the first question; these results were utilized in experiments at Florida Institute of Technology’s wave tank to observe oyster movement at specific wake heights. The field and wave tank experiments combined provide compelling evidence to conclude that wave energy resulting from boat wakes in ML is sufficient to dislodge oyster clusters from sediment and ultimately cause them to move, resulting in dead reefs. Model selection is being used to determine which variables most influence the observed responses.
