Updated: Aug 19, 2022
Ever wondered how the oysters are grown and how the taste and texture of oysters vary depending on the method of farming. As discussed in a previous post, different culturing methods can produce totally different oysters, and there are many of them! Oysters growers select their preferred grow-out method based on a number of factors like geography, climate, potential predators, and the regulations involved. We're going to touch base upon the most common methods in order to give you a peek into this oyster world and also shed some light on the superfood oysters.
Bottom vs. Off-Bottom
The bottom culture method means the oysters are grown on the ocean bottom, and in the off-bottom culture method oysters are grown without touching the bottom. Oyster farmers may use both methods over the course of an oyster's life to achieve a desired look or yield.
Both the methods have their own advantages and disadvantages. The main benefit of bottom culturing is the ability to produce robust and hearty shells. But the greatest disadvantage to this method is that growers can lose many oysters to mother nature. Oysters may die from suffocating under the bottom, get attacked by predators, or become frozen in ice that takes them out into the ocean. Every oyster lost is one less oyster a grower can sell for income.
Relatively, the off-bottom culture methods are advantageous over the bottom culture in the following respects.
Relatively rapid growth and good meat yield.
Facilities three-dimensional utilization of the culture area.
The biological functions of the oyster such as filtration feeding etc. are carried out independent of the tidal flow,
Silting and predatory problems are negligible.
There is a huge variety of off-bottom methods some of which are:
Cage culture: They house oyster grow-out mesh bags and keep them secure from floating away or touching the bottom. Cages require a pretty stable bottom because they are quite heavy and may sink into the mud if the bottom is too soft.
Rack-and-bag culture: culture: In rack-and-bag culture, oysters are placed into oyster grow-out bags, then tied to a steel rebar rack. This method is highly dependent on the tidal range of an area. The area would need low enough tides for growers to access the bags
Rack-and-tray culture: In the tray culture, oysters are grown in oyster grow-out trays. These trays have the same function as oyster grow-out bags and can be stacked to conserve space.
Suspended culture: In a suspended culture, the oysters are usually suspended from a buoy that floats on the surface of the water. In other words, the oysters are hanging underwater and they rise and fall with the tides. As the tide goes in and out, the bags are constantly flipped and moving up and down. Suspended culture oysters are constantly getting wave action.
Surface culture: For surface or floating culture, growers can choose from many different types of gear, systems, and equipment, but essentially, all surface culture gear will float on the surface of the water. Surface culture oysters typically never go dry and get a ton of wave action that naturally tumbles them.
The farming of oysters and other shellfish is relatively restorative environmentally and holds promise for relieving pressure on land-based protein sources. Restoration of the oyster population is encouraged for the ecosystem services they provide, including water quality maintenance, shoreline protection, sediment stabilization, nutrient cycling and sequestration, and habitat for other organisms.