The success of an oyster garden depends on both the site and the amount of effort the gardener puts into it. For those who are interested and able, oyster gardening can be a pleasurable and tasty pastime. Just like a traditional vegetable garden, an oyster garden must be planted with seed, tended during the growing period, protected from pests, and harvested when ready. The most successful gardeners, vegetable or oyster, are those who are best educated about all aspects of their “crop.”
It is vital that you adhere to all rules and regulations regarding the culture of oysters in your state waters. A permit may be required, and there may be regulations for handling or harvesting oysters. Before starting your garden, contact your local marine resources management agency to find out what regulations apply. Not all coastal states permit individual oyster gardening.
It is important that your oyster garden neither interfere with navigation nor adversely affect natural resources, such as shading submerged aquatic vegetation.
Consuming contaminated oysters can cause serious illness. Commercial shellfish harvesters are strictly regulated to ensure that a wholesome, healthful product is delivered to the public. Oyster gardeners must understand the potential health risks and be prepared to follow the same rules and regulations that govern commercial production. Not doing so can put your health and the welfare of the commercial oyster industry at risk. Contact your state shellfish sanitation control agency (which is usually associated with the state department of health) for their rules and regulations regarding oyster gardening. Your state shellfish sanitation control agency is responsible for classifying waters as to their appropriateness for harvesting oysters for consumption. Raising oysters in “other-than-approved” waters is not advised because they will accumulate bacteria and viruses that could cause illnesses.
Even pristine waters can contain bacteria that can cause illnesses at certain times of the year. The website for the Interstate Shellfish Sanitation Conference (www.issc.org) contains information on shellfish safety and provides the contact information for state shellfish sanitation control agencies.
For more information on the health implications of oyster culture, see SRAC Publication No. 4902, “Shellfish Handling Practices—Shrimp and Molluscs.”
If oyster gardening is a legal pastime in your area, the next step is to determine whether your gardening site is conducive to raising oysters. To evaluate a potential site, consider water salinity, water depth, site exposure, dissolved oxygen, and food availability. The presence of wild oysters at your site is a good sign that your location will support your gardening activities. Additional information can be found in SRAC Publication No. 432, “Cultivating the Eastern Oyster, Crassostrea virginica.”
The salinity of the water at your site will influence the growth rate of your oysters and whether they may become exposed to oyster-specific diseases. Generally, oysters require water salinity of at least 8 parts per thousand (ppt). The higher the salinity, the faster oysters grow.
Water salinity is measured as grams of salt per liter of water, or ppt. You can measure salinity at your location using inexpensive equipment such as a hydrometer, which can be found at pet stores that sell saltwater fish. It is a good idea to keep records of the salinity at different times of the year, under varying environmental conditions (for example, after a rainfall), and at different tidal cycles. This could help you make decisions about your oyster gardening activities.
There are two diseases specific to oysters than can have a devastating effect on your crop, though the diseases do not affect humans. Both diseases are caused by protozoans.
The first is MSX (Haplosporidium nelsoni), and the second is Dermo (Perkinsus marinus). MSX organisms cannot live in salinities below 10 ppt. In fact, the pathogen can be completely eliminated from infected oysters if the oysters are held in salinities below 10 ppt for 2 weeks. Dermo can survive in salinities below 10 ppt, but it will not kill oysters at that level. Should the salinity level rise above 10 ppt, Dermo can become quite deadly to oysters.