Monday, 26 May 2008

Oyster gardening

Ecologists are so enthused by the role of the oyster, that a series of oyster gardening programmes have been devised for hobby farmers with access to the water to grow on their own spat and help restock the reefs. The Maryland programme alone has more than 1000 volunteers. It is not as difficult as it might seem.

The spat are reared in hatcheries and given to the volunteers to grow on in either wire cages dropped by the side of a pontoon or in floating baths which have the advantage of keeping the oysters 24/7 in the richer diet of plankton near the surface. To be a good oyster gardener you have to keep watch that your float or cage does not bang against the sides or the noise frightens the oysters and causes them to close up. You also have to be diligent in winter to make sure they are always under the water because although an oyster can tolerate sub zero temperatures in the water, a frost in the air will kill them if they are exposed.

Instead of digging, an oyster gardener will have to lift their garden out of the water once or twice a week to desiccate the garden, to allow the sunlight and the dryness to kill off invading algae. They also need a good shake each day to make sure any dirt or debris falls away and does not clog up the garden, and once a week a good watering with a hose pipe to keep them clean. Plus the good oyster gardener has to keep a canny watch for oyster predators, especially worms.

In estuarine ecology oyster reefs have particular attractions. They make use of local materials, they are self sustaining, they have a dramatic impact on the marine environment, they protect the banks from erosion, all of which represent a low cost, low energy natural resource to stabilise the rivers.