Part 4 - Amazing Aquaculture!

An oyster hatchery.

Aquaculture is when people help fish, shellfish, or aquatic (water) plants to grow, often because they can't grow very well on their own anymore. It's like farming, but under water! Aquaculture is not a new invention - it was even practiced by the ancient Greeks! For almost 8,000 years people have been putting oyster "catchers" like shells, tree limbs, ropes, wires, and other objects in areas where gentle currents would bring the tiny baby oysters floating by.

Oysters that have attached to a branch in the water.

The baby oyster "spat" would attach themselves and "set." Later, these young oysters would often be moved to other areas to grow until they were harvest size.

Many countries in Asia have used aquaculture for generations to help raise fish and shellfish for their people. People have always gathered food from nearby waters. As more and more people settle near the water's edge the natural conditions of the waters often changed, becoming more polluted. This makes it difficult for oysters, and other animals and plants who live in the water, to grow and thrive. This has happened on our own Chesapeake Bay and in parts of Asia. Today, people are continuing to develop aquaculture techniques to help critters like the oyster to grow and replenish. Not only are oysters tasty to eat, but remember, they are natural water filters that help to keep our waters clean and clear.

In this country, oysters are often raised in floats.

The oysters are spread across the bottom of the floating wire mesh and PVC (a white plastic pipe) float. The oysters can rise and fall with the tides so they are always close to a good supply of food (algae). These floats can be used over and over.

Oyster shells in mesh bags give baby oysters ("spats") a perfect place to attach to and call home.

Another very inexpensive way to provide a habitat for the tiny oyster spat is to fill a plastic mesh bag with oyster shells. The bags are suspended by rope into the water, usually from a dock. The oyster spat are "seeded," or they can float by and attach to themselves to the shells. Later the bags can be emptied over an existing oyster "bed" so that the little oysters can grow.

U.S. Naval Academy midshipmen volunteers help relocate young oysters into existing oyster "beds."

Volunteers "planting" oysters.

One way that shellfish are raised in parts of Asia is to suspend "bags" of shells along lines that reach down into the water. These aquaculture cages hold shells that the oyster spat can land on and attach to in order to grow.

If you think that you understand some of the ways oysters are "farmed" click on the "Ahead" button to learn about the controversy that faces oysters in the Chesapeake Bay.