RECOVER MAP 3.2.4.4 Present and Past Distribution of Oysters in South Florida Coastal Complex - Whitewater Bay, Oyster Bay, Shark to Robert's Rivers

This project examined that past and present distribution of oyster reefs in the western Everglades from Lopez River to Shark River / White Water Bay complex. Using geological, geochemical, and biological techniques, the distribution of oysters (past and present) and the influence of environmental factors on oyster reef development were examined. The study examined two phases: (1) the past distribution and history of reef development during late Holocene and the influence reef development has had (or not had) on coastal geomorphology, and (2) the present distribution of oyster reefs and their physiological and ecological state in the Everglades coastal complex. This distribution and state of health is presumably indicative of the water quality, specifically the salinity and sedimentologic regimes of these watersheds.
To quantify the distribution of extant reef-building organisms within the study area, oyster reefs within seven estuaries were mapped and a spatial analysis was performed. Furthermore, the presence of oysters encrusting fringing mangrove prop-roots was mapped to determine whether apparent trends in oyster reef distribution were the result of water quality or substrate limitation. The spatial analysis was conducted by calculating the total area of oyster reefs within five quadrants located along the estuarine axis within the Chatham, Lostmans, and Broad Rivers. These data were then compared to the results of Savarese et al. (2004) that used similar techniques to quantify the distribution of oyster reefs within Blackwater Bay, Pumpkin Bay, Faka Union Bay, and Fakahatchee Bay of the Ten Thousand Islands (TTI). Results from the comparison show that oyster reefs are relatively well distributed throughout the TTI, while the distribution of oyster reefs within the estuaries composing the Everglades Estuarine Tract (EET) are restricted to the mouths of these rivers. This is likely the result of regional differences in watersheds producing distinct water quality in the EET and TTI.
In order to document historic coastal processes and predict future responses of those processes to accelerated sea-level rise (SLR) associated with global warming, a stratigraphic study was undertaken. To document the regional stratigraphy five sediment core transects, each containing 4-6 cores, were completed from the Fakahatchee estuary (TTI), Chatham River (transition region), Lostmans River (EET), Broad River (EET), and the inner bays of the EET.
To characterize the present distribution of oyster reefs, in addition to spatially mapping their distribution, oyster health measures (disease prevalence and intensity of the oyster disease Perkinsus marinus, condition index, reproduction, spat recruitment, growth and survival of juveniles, and living densities of oysters) were examined along a salinity gradient in a typical estuary, Lostmans River.