oysters develop their shells faster and may also be included in the water processing prior to introduction to the tanks. This latter cultivation technique may be the least susceptible to predators and poaching, but is the most expensive to build and to operate. The Pacific oyster M. gigas is the species most commonly used with this type of farming. Boats During the nineteenth century in the United States, various shallow draft sailboat designs were developed for oystering in Chesapeake Bay. These included the bugeye, log canoe, pungy, sharpie and skipjack. During the 1880s, a powerboat called the Chesapeake Bay deadrise was also developed. Since 1977, several boat builders in Brittany have built specialized amphibious vehicles for use in the area's mussel and oyster farming industries. The boats are made of aluminium, are relatively flat-bottomed, and have three, four, or six wheels, depending on the size of the boat. When the tide is out the boats can run on the tidal flats using their wheels. When the tide is in, they use a propeller to move themselves through the water. Oyster farmers in Jersey make use of similar boats. Environmental impact The farming of oysters and other shellfish is restorative environmentally, and holds promise for relieving pressure on land-based protein sources. Restoration of oyster populations are encouraged for the ecosystem services they provide, including water quality maintenance, shoreline protection and sediment stabilization, nutrient cycling and sequestration, and habitat for other organisms. Since there has been a decline in oyster population Oyster reef restoration has been huge in the past decades and a native Olympia oyster restoration project has taken place in Liberty Bay, Washington. Oyster farming in the Chesapeake Bay has minimal to positive impacts on the surrounding environment, and numerous oyster restoration projects are underway in the Chesapeake Bay. In the U.S., Delaware is the only East Coast state without oyster aquaculture, but making aquaculture a state-controlled industry of leasing water by the acre for commercial harvesting of shellfish is being considered. Supporters of Delaware's legislation to allow aquaculture cite revenue, job creation, and nutrient cycling benefits. It is estimated that one acre can produce nearly 750,000 oysters, which could filter between 15 and 40 million gallons of water daily. Other sources state that a single oyster can filter 24–96 liters a day (1–4 liters per hour). With 750,000 oysters in one acre, 18,000,000-72,000,000 liters of water can be filtered,