In January of 1996 the tank barge, North Cape, struck ground off the coast of Rhode Island spilling approximately 828,000 gallons of No. 2 heating oil into Block Island Sound. The results of over 30 studies of potential resource injuries caused by the spill were reviewed and a variety of experts in relevant scientific and technical disciplines were consulted. Based on this work, it is believed that the spill caused significant injuries to biota in the offshore and salt pond environments and to a variety of birds. A comprehensive restoration plan was developed and projects were implemented for shellfish, American lobster, piping plover, common loon, and sea ducks. Projects were also implemented to restore alewife runs in the salt pond watersheds as compensation for lost recreational fishing opportunities, and open space lands have been protected to compensate for losses to other marine and salt pond organisms. This particular case study focuses on the shellfish restoration project which was an effort to restore quahog, bay scallop and oyster populations in the coastal Rhode Island salt ponds following injuries caused by the North Cape oil spill.
Approximately 1.0 million kilograms of bivalve biomass were lost (direct mortality plus production foregone). The majority of the injury was to surf clams, (Spisula solidissma), of which 19.4 million animals were killed, resulting in a loss of 970,400 kilograms biomass. The goal of the restoration was to fully address the impacts to shellfish by returning injured natural resources to their pre-spill (baseline) conditions as well as compensate for interim losses of the shellfish resources. This was attempted by replacing the quantity of biomass (direct mortality plus forgone production) lost due to the spill. This replacement biomass is measured as the wet tissue weight of animals added to the system (stocked) plus weight added by the growth of stocked shellfish. Aspects of the restoration included stock enhancement and restoration of quahogs, bay scallops and oysters through nursery, spawning sanctuaries, and reseeding projects.
Results from the research studies and monitoring have aided in developing effective methods for restoration and management of shellfish species. Cost effective methods of rearing shellfish have been developed, factors effecting survival (seed size, stocking density, available habitat, disease, etc) have been identified, the importance and value of monitoring has been demonstrated, and community interest and awareness of Rhode Island's premier shellfish industry has been fostered by recruiting citizens to be actively involved in the restoration. The knowledge gained through these restoration activities will aid in the future management of shellfish so that they continue to provide ecological services to the Rhode Island salt ponds and Narragansett Bay.