COMMERCIALIZATION OF HARD CLAM (Mercenaria mercenaria) MARICULTURE IN SOUTH CAROLINA: PRELIMINARY REPORT1

Results from both previous and ongoing investigations on hard clam culture in South Carolina indicate a reasonable commercial potential for intensive clam culture on an industrial scale. To assess this potential and provide an appropriate economic feasibility analysis, the State of South Carolina, in cooperation with private industry and the U.S. Office of Sea Grant, has established a demonstration scale hard clam culture project near Charleston, S.C. The project operates on a two-stage grow-out protocol: raceways are used to provide initial grow-out (to 10 mm) and allow acclimation and disease monitoring for imported seed; final grow-out is accomplished in field units which provide protection from predators and substrate for support and orientation. Seed clams ranging in size from 300 μ to 10 mm are imported from commercial hatcheries, held in the raceway system for growth and observation and transferred to field units as they acclimate or attain minimum field planting size. Using this protocol, over 2.7 million seed are being planted in South Carolina estuaries over a 13-month period (October 1980-October 1981). Field units are stocked at three densities, 2,150, 4,300, and 6,450 m-2, using both intertidal and floating (raft) formats and a variety of substrates (crushed granite, chromium oxide slag, coarse sand, etc.). Units are sampled monthly to determine growth and survival, and these data are correlated with coincidental monitoring of various environmental parameters (temperature, salinity, particulate, dissolved, and total organic carbon, chlorophyll a, and turbidity). This paper reviews results to date and provides descriptive data concerning the raceway system, field units, and support equipment.