Aqua Culture: Oyster Farming

Oyster Farming – What’s to know

Oyster farming is a practice where oysters are cultivated for human consumption. This has most likely developed at the same time as pearl farming which oysters were farmed in order to produce pearls. Oyster farming is not a new practice, it has been around since Roman times. They cultivated oysters in the United Kingdom and then shipped them off to Italy. France has been dependent on farmed oysters since the 18th century.

So how are they grown?

Oysters like to grow in estuaries whose waters are not as salty as seawater but are more saline than freshwater (known as brackish water). When they are being cultivated, the water temperature and salinity are carefully controlled. This ensures optimum conditions for mating and development. There are three main methods used when cultivating oysters. Each time, the oysters are grown to the size of “spat” which is the stage that they attach themselves to a substrate, which is known as the culch or cultch. The loose spat may be then allowed to develop and mature to form oysters with small shells (also known as seed). At either spat or seed stage, then they are set out to mature. It is at this maturation stage that the choice is made.

Method 1 – the ‘baby oysters’ are distributed over the oyster beds and left to mature naturally. Then they will be harvested using the methods used for fishing for oysters – methods such as dredging.

Method 2 – the spat or seed are but in bags, sacks or cages and suspended from the bottom. When they are ready, then the bags are lifted and the mature oysters retrieved or they wait till the bags/cages/racks are exposed at low tide then get them then. This method is pricey but it helps preservation of wildlife

Method 3 – the baby oysters are placed in a culch and then put in an artificial maturation tank. This is usually fed with specially prepared water which accelerates the the growth of the oysters. Minerals such as calcite, aragonite and carbonite minerals are in the water which helps the development of their shells at a more rapid rate. Although this means that the oysters are the least susceptible to predators, it is expensive.

Oyster farming is relatively easy on the environment but it is not without its problems. Although the farms are there to protect against predators, it can interfere with the movement of marine life such as fish and otters. If boats are used to maintain the farm, then that could mess with the natural environment. But remember, oysters help the environment, by filtering out micro-organisms that can become problematic and unhealthy -and they keep water chemistry in balance.

So I got the facts, so how much is the average fresh oyster?

Well, they tend to be sold in batches although you can get them individually priced. Expect to pay about $1-3 per oyster. If you want to know more, click here. They are pricey but worth it.

Which ones are good for cultivating?

The Eastern oyster (known as the Atlantic oyster or Virginia Oyster) are the most popular commercially. The Pacific Oyster, Belon Oyster and Southern mud oyster are also popular.

After they have been harvested, how long will they keep?

They can be kept alive for a few days in a fridge operating at about 5-8 degrees centigrade (40-45୦F). DO NOT take them out of the fridge. Do not “seal” them in a container. They will die if not in exposed to air.

When should I throw them out?

Well obviously, if they start to smell bad, get rid of them. Any that are gaping and fail to close when they are tapped should be discarded.

Is there a difference between farmed oysters and wild caught oysters?

There shouldn’t be. It is just the way they are brought to maturity and harvested that is different. But hey, why don’t you try them and let us know what you think.

Did you know…that the average oyster filters up to 15 gallons of water (that’s 68 litres or 120 pints to you and me!) which removes nitrogen from the water…Awesome!

Hope you have enjoyed this. Enjoy the ocean’s aphrodisiac knowing that they are good for the environment whether they have been farmed or caught and that you are doing  your heart (maybe not your wallet…but hey like the L’oreal advert says, they’re “worth it” ) a load of good…

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