OYSTER ( Crassostrea virginica ) RECRUITMENT STUDIES IN THE GREAT BAY ESTUARY, NEW HAMPSHIRE

Oyster populations in New Hampshire’s Great Bay Estuary have experienced dramatic declines similar to populations along the east coast. These declines have caused ecosystem degradation in estuaries and prompted a focus on oyster reef restoration. Despite the large use of procured funds dedicated for oyster reef restoration, few quantifiable successes have occurred. Currently, there is no rigorous method for determining where a restored reef would have the highest probability for long-term success. However, consistent and substantial natural recruitment is a major factor to consider. In this research, I identify historic trends in oyster populations, quantify the success and failures of restored reefs, and examine how proximity to a native oyster reef affects recruitment. Oyster populations throughout the Great Bay Estuary declined significantly after the introduction of two diseases, MSX and Dermo, in 1995. Although, populations rebounded after large spatfall events, three to four years after these events population levels declined, probably mainly a result of disease. My results suggest oyster recruitment is significantly greater on natural oyster reefs compared to restored reefs. There was also a significant increase in recruitment on restoration reefs less than 1 km from a native reef compared to restoration reefs greater than 1 km from a native reef. Furthermore, recruitment decreased significantly as proximity from a native reef increased. Results suggest that restoration efforts should consider extending the natural boundary of native oyster reefs to provide the greatest potential for natural recruitment and thus long-term reef development