Elementary Ecology: The Benefits of Aquaculture

Dr. Robert Rheault has a shellfish farm called Moonstone Oysters near Point Judith. Also president of the East Coast Shellfish Growers Association and secretary of the Ocean State Aquaculture Association, he is committed to promoting public education about aquaculture.

His enthusiasm captivated South Kingstown's 1st through 5th graders last fall. One would never have guessed that this young audience, unlike his customary graduate students and members of Congress, had drawn beads of sweat across Bob’s brow during his many hours of preparation.

Shellfish live in most of the world's seas and some of its lakes and freshwater rivers. Starting as microscopic specks of dust, one million baby oysters can fit in your hands like grains of sand. Their shells are so transparent you can see their hearts beating.

Some farms grow shellfish in floating upwellers, where plastic mesh cages, bags or baskets let water through while keeping algae out and protecting babies from predators. These are hung, shaken and flipped in the sun to clean the water-blocking algae and sea squirts. This farm gear creates tremendous marine habitats and improves species diversity, serving as artificial reefs where juvenile fish and crustaceans can live, find food and refuge, and breed.

With no books to consult, protecting baby shellfish from predators is a challenge. Blue crabs, for one, just won’t let go and can consume 200 baby clams an hour. Once the size of a quarter, shellfish can resist crabs and starfish, and settle down to grow in sand or on rocks.

Shellfish improve water quality as they feed by filtering microscopic plants from water. One oyster can clear over 15 gallons a day—a small farm, 30 to 100 million gallons. They also remove nitrogen, lower bacterial counts, improve water clarity, and diminish algal blooms. And they filter silt from the water—better light penetration helps oxygenate deeper water and can improve eelgrass survival.

Clean water is critical to marine life, especially when grown for food. Anything thrown down street or indoor drains, especially poisons or chemicals, and excess lawn fertilizer, pet waste, and trash on beaches can damage marine life.

Illustrations and quotes are student reflections when asked, "How does aquaculture help oceans, and what can you do to help keep marine habitats clean?"

“My Place” launched S.K. Schools’ Community Learning Project with local heritage, natural history, and natural resources. “My People” is addressing basic needs and diversity, and in the spring, “My Environment” will focus on natural processes and local flora and fauna.

By Rian Smith