Quantifying the nutrient bioextraction capacity of restored eastern oyster populations in two coastal bays on Long Island, New York

Abstract

Degradation of coastal areas due to eutrophication is becoming evident on a global scale. Like many estuaries, Jamaica Bay and Great South Bay, NY have been impacted by eutrophication at varying degrees. The eastern oyster, Crassostrea virginica, has been suggested as a way to remediate eutrophication through nutrient bioextraction. Eastern oyster populations were once abundant in both Jamaica Bay and Great South Bay. Overfishing, habitat destruction, and pollution have caused ecological extinction of populations in these regions. The abundance of oysters that once existed in these regions may drive the desire for restoration in these areas. Although appealing, invested individuals must be cautious to start restoration based on historical populations as indicators of potential for restoration. In order to determine the potential of eastern oysters to act as bioextraction tools in these areas a two year aquaculture-based assessment in Jamaica Bay and a five month aquaculture-based assessment in Great Bay were implemented. Our assessments revealed fast growth rates in shell height and tissue growth in these regions. Mean values of shell and tissue growth in the first-year season of growth (mid-June to mid-October) in Jamaica Bay 2010 were approximately 50.40mm and 1.54g, respectively. In 2011 in Great South Bay mean values over the same growth period were approximately 33.64mm and 0.84g. Results also showed high cumulative survivorship by the end of the first growing season. Average cumulative survivorship was 95.5% in Jamaica Bay and 75.5% in Great South Bay. Information from these physiological assessments was combined with a quantification of nutrient assimilation by oyster tissue and shell. Total nitrogen content of aquacultured oysters was of particular interest and was quantified by measuring total nitrogen content in the tissue and shell of oysters after the first growing season. Results reveal the average sized oyster to be approximately .19gN in Jamaica Bay and .11gN in Great South Bay.