Volunteers get oysters growing to help clean local waterways


“Honey, did you remember to water the oysters?”

Coastal Point • Monica Fleming: Dr. Allan Allenspach points out a baby oyster about same size as his fingernail. The oysters are grown in floats on shells until they reach about 1 to 1.5 inches in size, at which time they are transplanted near rocky riprap.Coastal Point • Monica Fleming
Dr. Allan Allenspach points out a baby oyster about same size as his fingernail. The oysters are grown in floats on shells until they reach about 1 to 1.5 inches in size, at which time they are transplanted near rocky riprap.

People who want to try out their green thumbs can grow vegetables, flowers or shrubs – or they could get really “green” and take a shot at growing oysters.

Because of a combination of pollution, over-harvesting and disease, oyster populations have diminished in the Delaware inland bays over the years. As an adult oyster can filter about 50 gallons of water a day simply by existing, they are considered an essential part of keeping the bays clean.

Oyster Gardening, a program managed by the Center for Inland Bays, allows volunteers to grow baby oysters, or spat, that range in size from microscopic to about 10 millimeters and beyond. About 110 to 115 volunteers throughout the inland bays watershed volunteer for the program and interest is so plentiful that there is a waiting list to join.

Volunteers just have to have a dock or bulkhead and access to the water. The CIB gets the larval oysters – a variety that is grown specifically to be disease-resistant – from the Rutgers University Institute of Marine and Coastal Sciences. They take a ferry ride to the University of Delaware’s College of Marine Studies in Lewes. Then the larvae are matched up with empty oyster shells recycled from local restaurants and placed in a big Jacuzzi-type pool of water so they can attach themselves to the shells. After that, the bags of inoculated shells are given to the volunteers, who drop them in their Taylor floats to grow.

Dr. Allan Allenspach, block captain for the oyster gardening program in the Bethany and South Bethany area, has been oyster gardening for about five years now. A former professor of zoology at Miami University in Oxford Ohio, one of the first things he did after retiring to South Bethany in 1998 was befriend the scientists at UD’s Lewes lab.

“It’s my scientific outlet,” he said of the program. He added that he many participants feel it is their small way of changing things for the better.

“It’s one of the few projects where volunteers can actually do something,” he said. “They can’t control the power plant or the fertilizer or pesticide runoff, but they can, in their own little way, having the floaters out here, and oyster gardening, do their part to clean the waters.

“Our little effort is like spitting in the ocean, but they love to do it,” he said of the volunteers.

He added that they are grateful to the South Bethany Property Owner’s Association, who contributed the $700 to buy the million or so larvae they needed to get their oyster gardening started this year.

Because it is a social project, many times neighbors just have to see a neighbor with oysters to want to get involved, said E.J. Calabala of the CIB.

“It’s easy public outreach because, once a week, we ask that the volunteers hose them off, and it’s pretty easy for the community to see what’s going on.”

While in the floats, they are constantly feeding on algae and the excess nutrients in the water, which allows for them to aid in water filtration. And, because the floats aid in keeping predators away from the spat, the oysters can easily survive – and thrive – to the point where they can be taken out of their equivalent of a baby’s playpen, usually two seasons after they started as larvae.

At the point they reach about 1 to 1.5 inches in size, the young oysters are taken out of the floats and placed into area of riprap, with hopes that they will mature and spawn – and, hopefully, continue growing. Because the canals have muddy bottoms, they don’t have much to grab on to there, so they are moved to the rocky areas near riprap.

“Just like the babies attach to the shells, the bigger oysters attach to rocks,” explained Allenspach. “And, if they have enough, maybe they’ll even reproduce and make more in other years.”

Calabala said 300 to 350 oysters can be in one float – so that, multiplied by 50 gallons (or about 15 while they are not yet adults), adds up to a lot of water filtration. The filtration the oysters provide, in turn, helps to clean up the inland bays.

For more information on oyster gardening and how to get involved, visit inlandbays.org.