Oyster Farming & Aquaculture
There are four main techniques for raising oysters in North America. Beach or Bottom Cultured (or Intertidal Cultured), Rack & Bag Cultured, Longline Cultured, Suspended Tray or Suspended Lantern Cultured. Each method imparts different qualities to the oyster flavor profile, texture, and shell characteristics. Two additional variations are Bag to Beach and Tumbling. Bag to Beach is a combination of Rack & Bag cultivation & Beach cultivation. Tumbling is a variation of Suspension Cultivation where suspended oysters are tumbled to increase shell strength and meat texture.
Beach/Bottom Cultured Oysters, also called Intertidal Cultured Oysters, are oysters which are raised on tidal beaches with sandy or rocky bottoms. These oysters are accustomed to fighting the tides, clamping tightly shut during low tides to preserve their “liquor” and to protect themselves against predators. Because of this “tough” life, beach raised oysters are hearty. They have hard, sturdy shells which shuckers like to work with. And their ability to close tightly, coupled with their hard shells, gives them a longer shelf life. Examples of beach cultured oysters include: Bald Point, Dosewallips, Fanny Bay, Marrowstone, and Totten Virginica.
Rack & Bag cultured oysters (also called On Bottom Cages) are grown in mesh cages or bags which are generally staked about one to two feet off the bottom. Oysters raised by the rack & bag method are protected from predators and do not become cramped for space as they grow. They also do not have to filter as much sand & mud in order to get nutrients, thus they grow faster. They develop a deeper cup than beach cultured oysters. However, if the oyster is raised entirely this way then they are pampered and their shells are brittle which makes them difficult to shuck without breaking. Examples of rack & bag cultured oysters include: Chelsea Gem, Hawk’s Point, and Jorstad.
Longline culture is a variation of off bottom culture where long ropes with seedling oysters attached are suspended. This suspension method is usually done horizontally and staked about one to two feet above the bottom in an intertidal region. But sometimes the lines are suspended vertically in deep water. Longline cultured oysters have a sturdier shell and firmer meats than suspension tray raised oysters because the longline does allow for more interaction with the environment and requires more tenacity for the oyster to remain attached to the line whereas cage oysters simply sit there. Examples of longline cultured oysters include: Shigoku
Suspended Tray Cultured Oysters
Oysters which are cultivated by the suspension method are the prima donnas of oyster. They are suspended, in mesh trays or a Japanese lantern shaped nets, in deep water their entire lives, protected from predators, mud, sand and silt. They have beautiful shells with deep cups, but they are an oyster shucker’s nightmare because their shells are brittle since they never had to fight for survival. Because of their brittle shell, it is best to use the Chesapeake Oyster Shucking Style, going in through the lip. Using the traditional Hinge Oyster Shucking Style on brittle shelled (new shell) oysters tends to result in breaking the shell of suspension cultivated oysters. The oyster flavor profile of suspended oysters tends to be clean, sweet & light, with meats which are tender. Examples of suspension tray cultured oysters include: Chef’s Creek, Emerald Cove, Pearl Bay, Sinku, and Snow Creek.
Bag to Beach Cultured Oysters
Oysters raised by the bag to beach method combine two oyster farming methods. Rack & bag oysters are taken from their pampered environment and put into the beach culture environment during their last 6 months before harvesting. This allows them to “toughen up” a bit, giving them stronger, less brittle shells and firmer meats. Examples of bag to beach cultured oysters include: Barron Point, Hammersley, and Little Skookum.
Some oysters which are raised by the suspension method are put through an additional step where they are periodically tumbled. This strengthens their shells and adds firmness to the meats. It also adds a distinctive look to the shell as it becomes smoother and develops a deeper cup from tumbling. The Kusshi Oyster is an example of this additional process in practice.
Tidal Basket or Tide Tumbled Suspension Tray
This is a relatively new cultivation method which was developed by Taylor Shellfish around 2008 and made its debut appearance with the Shiigoku oyster in 2009. Taylor’s method uses a stationary horizontal line to which suspension trays are attached. Each tray has floats attached to it in such a manner that as the tides eb and flow the trays naturally rise and fall causing the oysters to be gently tumbled. Thus the oysters are tumbled twice a day, which chips the edges of the shells giving them a uniquely smooth, “clean” edge and deep cups.
This tumbling process also helps to give the meats more firmness. Normal suspension tray cultivated oysters have very little “chew” to them because the oyster just sits there and does nothing. But a tumbled oyster has to work a little to protect itself during tumbling to keep its shell closed tight.
Additional Oyster Cultivation Info
For an in depth explanation of oyster cultivation including growing of oyster spat, varieties of spat, nurseries, spawn management, upwellers and so on checkout this info about Oyster Culture.
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