Mariculture

People grow food in the sea.

This is called mariculture. Farmers grow fish like salmon in big nets. They also grow plants like seaweed.

Some farms use tanks on land. These tanks hold salt water from the sea. Farmers also grow shrimp and oysters. They can even make pearls for jewelry.

It is a busy way to farm the ocean.

Mariculture is a way to farm in the sea.

People grow many things in saltwater. They grow fish like salmon and cod. They also farm shellfish. This includes shrimp, oysters, and clams. Some farmers even grow pearls for jewelry.

There are different ways to farm. Some farms are on land. These use tanks or ponds filled with seawater. This is called onshore mariculture. Other farms are in the ocean. These use nets or cages.

Some cages sit near the shore. These are inshore farms. Other farms sit far out in the deep, open ocean. This is a new way to farm.

Farmers also grow plants called algae. This includes seaweed. Algae can be used for food or fuel. It can even help clean pollution. Some people use seaweed to help wild fish populations.

Farmers must be careful. They must pick the right spot. They look at water depth and storms. They also watch for waste. They want to keep the ocean healthy for everyone.

Mariculture is a special way of farming that happens in seawater. People use it to grow many different living things for food and other products. This can include finfish like salmon and cod, or shellfish like shrimp and oysters. Some people even farm algae, which includes tiny plankton and seaweed. Mariculture is important because it provides many things we use every day. It can produce fish meal, cosmetics, and even cultured pearls for jewelry.

There are three main ways that mariculture works. Onshore mariculture uses manmade ponds, tanks, or raceways filled with seawater. In this method, the water itself provides the food and nutrients for the species. Inshore mariculture happens in coastal waters like bays or estuaries where the tide moves the water. Farmers here might use nets, pens, or long-line arrays of floating cages. Finally, open ocean aquaculture happens in the deep, high-energy parts of the sea. This is a newer way to farm using cages that are moored or towed.

History shows that people have long understood how to work with the sea. For example, the Māori people of New Zealand have traditions of farming shellfish. This includes the ancient practice of moving species like the toheroa to new areas. Today, mariculture is growing very fast because of new technology and better food for the animals. Scientists are also learning more about how different species live in the water. This helps farmers grow more food while keeping the animals healthy.

Many different places around the world now use these farming methods. In the United States, commercial facilities have raised threadfin near Hawaii and cobia near Puerto Rico. The largest deep water open ocean farm in the world is currently raising cobia. This farm is located 12 km off the northern coast of Panama. Other countries using open ocean methods include Australia, Chile, China, France, Ireland, Italy, Japan, Mexico, and Norway.

Farmers must be very careful to protect the ocean environment. They have to pick sites with the right water depth and current speeds. If they feed fish too much, waste can fall to the seafloor and change the habitat. Sometimes, fish can accidentally escape from their pens into the wild. In 1999, a storm caused 5,000 Siberian sturgeon to escape into a French estuary. To prevent this, some farmers use land-based tanks that are completely isolated from the sea.

Mariculture is a specialized branch of aquaculture focused on the cultivation of marine organisms within seawater. This practice involves raising various species for food, animal products, and industrial uses. It is a vital part of global food production and resource management. Mariculture can produce high-value items like cultured pearls for jewelry and cosmetics. It also provides raw materials such as fish meal, nutrient agar, and even bioplastics. By farming in the ocean, humans can harvest resources in a way that mimics natural ecosystems.

The mechanism of mariculture depends on the specific environment used for cultivation. In onshore mariculture, farmers use manmade tanks, ponds, or raceways. These structures are supplied with seawater rather than fresh water. A key feature is that the water column provides the necessary nutrients. This reduces the need for artificial feeding and preserves the natural diet of the species. Inshore mariculture takes place in littoral waters or estuarine environments like bays and brackish rivers. Here, the tides help move and refresh the water. Farmers use tools like artificial reefs, nets, or long-line arrays of floating cages moored to the seabed.

There are three distinct types of mariculture based on their location. Onshore mariculture is often used for farming algae, such as plankton and seaweed, as well as shellfish like shrimp and oysters. Inshore mariculture focuses on species in tidal zones, using pens or cages. Open ocean aquaculture, or OOA, is a newer and more complex approach. It involves raising organisms in exposed, high-energy environments far from the coast. OOA uses cages or long-line arrays that are either moored or towed. This method has the potential to combine with offshore energy systems, such as wind farms, to use ocean space more effectively.

History shows that marine farming is both an ancient and a modern science. The Māori people of New Zealand have long-held traditions of farming shellfish. This includes the practice of *ahumoana tawhito*, or ancient aquaculture, where species like the toheroa were translocated. Modern mariculture has expanded rapidly over the last twenty years. This growth is driven by new technology and better formulated feeds. Improved biological understanding and better water quality in closed systems have also helped. Today, commercial open ocean facilities are active in many nations, including Chile, China, Norway, and Japan.

The scale of these operations is significant and global. In the United States, commercial facilities have operated in Hawaiian and Puerto Rican waters. The largest deep-water open ocean farm in the world is located 12 km off the northern coast of Panama. This specific facility focuses on raising cobia in highly exposed sites. In the realm of algae, researchers are exploring "marine permaculture." This concept uses artificial upwelling and submerged platforms to replicate natural seaweed ecosystems. If seaweeds sink below a depth of one kilometer, they may help sequester atmospheric carbon.

Different species require different management techniques within these systems. Shellfish farming is often a self-supporting system. Species like mussels, clams, and abalone do not require added feed, fertilizers, or antibiotics. They can even be used in integrated multi-species cultivation to utilize waste from other organisms. Finfish, such as salmon and cod, are managed differently. In intensive systems, farmers often use manufactured, nutritionally complete pelleted feed. This is sometimes delivered by automated computer-controlled systems to ensure efficient growth.

Despite its benefits, mariculture faces environmental and social challenges. One concern is the accumulation of waste from cage cultures. If fish are overfed, excess food can settle on the seafloor and smother invertebrates. Another major issue is the escape of farmed animals into the wild. For example, in December 1999, a storm caused 5,000 Siberian sturgeon to escape into the Gironde Estuary in France. Such escapes can lead to genetic pollution or the introduction of invasive species. To manage these risks, farmers must carefully select sites based on water depth, current speeds, and storm shelter.