A Mechanical Oyster Harvester for South Carolina Estuaries

A mechanical oyster harvester has been developed for intertidal oysters (Crassostrea virginica). The harvester is hydraulically powered and mounted on a 16 m steel hull vessel designed for its operation. The objective of this research was to produce a machine that would efficiently harvest oysters while doing minimum damage to the oysters and the fragile shell matrix that supports them. Results of three years' testing show harvest rates of 18 m3/h. Damage to the shell matrix was almost undetectable while damage to the harvested oysters was about 5%. The harvester can operate at depths of 1 to 3 m with the position of the head controlled automatically. Bottom contact force is adjustable and regulated automatically during harvest to minimize bottom damage. The harvesting head can pitch or roll up to 0.35 rad to follow bottom contours. The harvester is being used by the state of South Carolina for oyster bed management and transplanting of oysters from polluted areas to public shellfish grounds.