UTILIZING SHORELINE RIPRAP FOR STOCKING EASTERN OYSTERS (Crassostrea virginica)

The decline of Eastern oyster populations over the past century is due to various common factors. Two basic restoration techniques exist: restore substrates or increase broodstock. Millions of dollars are spent yearly on oyster restoration practices, yet small community based restoration programs are still an effective technique to improve aquatic habitat impacted anthropogenically. Creating a patchwork of oyster habitats throughout an estuary, such as placing oysters in multiple riprap locations, may be the best method to effectively restore ecosystem functionality in the Delaware Inland Bays. The Delaware Oyster Gardening Program increases broodstock by growing oysters in floating aquaculture gear. In order to make room for a new oyster cohort biennially, oysters are collected from the volunteer gardener's floats every spring. These oysters are either utilized for research or restoration efforts, as the oysters are not eaten or sold. Numerous resources are required to constructed oyster reefs, which make oyster enhancement projects difficult, and are not always successful. Riprap has increased the complexity of shorelines in developed regions, thus providing suitable substrate for oyster stocking at no extra cost to managers. Two year old oysters were planted between rock crevices, and after one year in the riprap, showed 50% survival. Medium sized ripraps (0.4-0.6m rock diameter) are ideal for conducting survival experiments and general oyster stocking. It is important to note that all riprap is not homogeneous in nature, as size and depth of boulders vary, which will influence site selection depending on the goals of the oyster restoration program. Also, a number of sites monitored in this research are in close proximity to the recommended sites for oyster aquaculture and may provide important comparison for future aquaculture research.