We in the Lowcountry know that February is peak oyster eating time, the Lowcountry Oyster Festival and Sullivan’s Island Fire Department Roast are annual events that celebrate the oyster and the social aspects of an oyster roast. Oysters at these events are likely from Apalachicola, Florida or the east coast of Texas not the Lowcountry. This is mainly because they serve single oysters which are easier to eat than cluster oysters which we have here in the Lowcountry. However, most folks also know that the local oysters are the best oysters in the world. The sweet combination of oyster meat and the salt water make for an aphrodisiacal cocktail that can not be beat.

The area north of Charleston Harbor to the Santee River has some of the most prolific oyster beds in the North America. Charleston and Beaufort County generate over 90% of the state’s oysters. These oyster beds, particularly those adjacent to Mount Pleasant and Awendaw, are being threatened by pollution over-harvesting, over-development and human activities that destroy their habitat. Eastern oysters, Crassostrea virginica, grow on intertidal reefs of dead and live oysters. They begin their life as males and then switch gender to female to spawn the millions of gametes (eggs and sperm) into the water column. During the warm months between May and October, these spat seek a place to make their home. Dead oyster shells are the preferred structure for these baby oysters to attach themselves to. They are also known to cluster or spoon one another to form large masses of oysters, which eventually suffocate their predecessors into the pluff mud as their weighty mass slowly sinks. The oyster filters water for its food. These bivalves open their shell and they take in water, 20 to 30 gallons per day, from which they get the nutrients to grow and live.

Good Water Quality = Good Oysters

An oyster’s dependence on water for nutrients is one of many reasons environmental water quality is so important. Oysters are considered to be a keystone species and good indicators of the health of estuaries. The SouthCarolina Department of Health and Environmental Control (SCDHEC) has water quality standards they monitor to ensure that oysters harvested for human consumption are grown in water that meets these standards. Mount Pleasant Waterworks (MPW) is held to strict standards for our wastewater discharge to Charleston Harbor. Stormwater runoff, rain water that picks up soil contaminants such as petroleum, pesticides, or fertilizers, contributes the majority of the pollution load on our local ecosystem. That is why SCDHEC closes oyster beds after large rains, when the pollution load is highest. They also close beds near marinas or wastewater discharges. In 2003 SCDHEC closed over 167,000 acres (over 30%) of shellfish beds, due to water quality issues or their proximity to marina or discharges.

Protecting our Precious Resources

Almost all of our human activities create pollution, our cars leak oil and airborne emissions that eventually end up in the water, we over fertilize our lawns and runoff carries the excess nutrients into the water, and we dump human waste and chemicals from our homes and businesses into the public wastewater system. MPW treats and removes about 95% of the pollutants, but a small amount eventually makes it into the water. MPW takes its role as a steward for the environment very seriously and works to provide a clean water environment for the oyster population to flourish in.

Not only do people enjoy eating oysters, live reefs help clean the water and provide habitat for all sorts of other animals such as sponges, small crabs, and fishes. Through filtration, oyster reefs can improve water quality a small amount by removing pollutants and controlling algal blooms. As we do our part to protect the oysters they are doing their small part to help the environment as well. Loss of oyster structure hinders the proliferation of the Eastern oyster. Since oyster health is highly contingent upon water quality, we must consciously reduce our impact on our ecosystem every day in a multitude of ways. One additional way is to reduce boat wakes which can cause clusters to dislodge and die. It is comforting to know there are ongoing efforts by the South Carolina Department of Natural Resources and federal agencies like National Oceanic and Atmospheric Administration to help restore and enhance oyster reefs, as well as, provide drop sites for shell recycling. Check out http://score.dnr.sc.gov for more information and the closest drop site. And remember, clean water means good oyster eatin’.

(Clay Duffie is General Manager of Mount Pleasant Waterworks and has more than 30 years of experience in water and wastewater management practice. He is a past President of the South Carolina Water Pollution Control Association and the SC Section of the American Water Works Association (AWWA) and has led numerous national seminars on environmental leadership and utility management issues.)