Oyster Aquaculture

By: Katie Doran and Mary Levine

What is Oyster Aquaculture?

Oyster Aquaculture is also referred to by "Oyster Farming". This means oysters are grown by humans for human consumption.

Where is Oyster Aquaculture used?

Oyster farms are found all over the world. The majority of them located in the United States, France, Japan, Korea and China. With many different farms found in each of those countries.

Some pictures of Oysters being harvested

How does Oyster Aquaculture work?

Most farms buy oyster seeds which they will grow. But about 12 oyster farms in the United States grow their own seeds. They choose the best oysters they have they put them into a warm tank, so the oysters grow gametes. Once they are ready, the oysters are moved onto spawning trays where millions of gametes are released. The gametes or now "free swimming larvae" are taken to another tank where calcium carbonate is added to the tank. Some farmers put ground up old oyster shells in the tank to provide calcium carbonate, while others now put the them into a calcium carbonate bowl. The larvae are kept under a constant flood of water and algae for about 5 weeks. Then they get moved to upwellers which again gives the oysters a constant flow of nutrients and water. After the oysters have grown big enough they are moved into black mesh bags and put in the river for about 6-8 weeks. Then the oysters will be big enough to move to the nursery which are a bunch of cages that sit on the bottom of the bay, where they will be located for about 2-3 months. The oysters are then tossed freely onto the bottom of the muddy bay where they will grow for 1.5-2 more years before they are ready for human consumption.

Government Regulations

There are different permits and licenses needed in order to harvest or farm oysters. Anyone taking part in oyster aquaculture must have a Commercial Fisherman Registration License (CFRL), Aquaculture Product Owners License, or Aquaculture Harvester License. There are different rules for what permit and license you need in order to participate, but they differ based on location and purpose of oyster farming.

Bycatch numbers?

Due to the ways oysters are harvested, the bycatch of other species is rare when collecting oysters. The bycatch of oysters is also rare because fishers try to avoid oyster farms as oysters can cause damage to their nets.

What would happen if the government banned Oyster Aquaculture?

There would not be enough wild oysters to sustain human consumption and the oyster population would quickly decline. This means that there would not be enough oysters to help clean the water as well as provide habitats for other fish. Also, without oyster aquaculture, it could severely affect the economy, seeing as oyster aquaculture is a main revenue source in many states.

Is Oyster Aquaculture environmentally sustainable?

Oyster farming is environmentally sustainable because oysters have little to no impact in the ocean. Oysters are self sustaining creatures meaning they do not require fish to survive, but they instead feed on tiny particles or plankton. Oyster farming does not require any chemicals or antibiotics in order to take place, so it does not affect the ocean or the environment around it. Lastly, oyster farming is beneficial to wild oysters because it reduces the amount of wild oysters that are caught. This is important because wild oysters have been suffering from population loss.

Why is Oyster Aquaculture not harmful for the ecosystem health?

Oyster aquaculture provides a variety of services to the ecosystem. The first is the creation of a habitat for myriad juvenile fish and crustaceans. As they grow, they form reefs in which these species live in. Oyster farming also stimulates nutrient cycling. This nutrient cycling is also known as denitrification. Denitrification is when the oysters remove nitrogen from particles that they eat through filter feeding. They use this nitrogen to either build tissues or they release it to the sediment in a biodeposit. This sediment breaks down the nitrogen and releases it into the atmosphere. This is very important in the ecosystem because nitrogen is one of the leading causes of algal blooms.

Ocean Acidification

One problem facing oyster farmers today is ocean acidification. The ocean water being used in hatcheries is directly from the ocean but it is very corrosive, which means it is eating the oyster shells before they have even developed. This means there is a shortage of oyster seeds to send out to the farms. Oysters need a high level of pH in order to grow. The increase of carbon dioxide in the ocean has made it more corrosive. Now nurseries monitor the imported ocean water and add sodium carbonate and eelgrass to help make it not as corrosive. But as more carbon dioxide is released in to our ocean, oyster aquaculture will continue to suffer.