For several years, SeaWeb has acted as a leading voice for sustainable aquaculture by identifying and analyzing key issues and solutions in aquaculture and promoting related science and industry breakthroughs that advance ocean conservation. From 1998 to 2005, SeaWeb ran the SeaWeb Aquaculture Center (previously the SeaWeb Aquaculture Clearinghouse) as a strategic resource for NGOs, foundations, media and policy makers. The Center provided scientifically credible information to a variety of stakeholders on the complex issue of aquaculture.

Today, SeaWeb maintains a comprehensive collection of regularly updated aquaculture resources that enables us to remain a leading voice in this evolving field.

Glossary of Aquaculture Terms

  • Aquaculture: Farming of aquatic organisms including crocodiles, amphibians, finfish, mollusks, crustaceans and plants, where farming refers to the rearing of these organisms to their juvenile and/or adult phase under captive conditions.
  • Biological pollution: Biological pollutants are animals, plants, or other organisms, the pollution of which refers to the introduction of an exotic species into a specific, non-native habitat.
  • Bottom culture: The culture of species such as oysters and other mollusks on the seafloor.
  • Effluent: The material flowing from an aquaculture facility into a treatment system or a nearby water body. The waste stream can include uneaten feed, feces, chemicals, and escaped fish.
  • Eutrophication: The gradual increase in nutrient concentration in a body of water. Eutrophication is a natural process, which happens gradually over time; however, it can be accelerated through the actions of human activity. An increase in nutrients leads to an increase in primary production. When the plants die the decomposition process depletes the water of oxygen resulting in anoxic conditions, thus rendering the environment unsuitable for most species of aquatic organisms.
  • Fishmeal: The primary protein source for farmed carnivorous fish. Small pelagic fish, such as anchovy, pilchard, herring, sardine, sand eel, sprat, and capelin, are caught, processed into fishmeal pellets, and fed to cultured organisms.
  • Flow-through system: Flow-through systems, or raceways, are a type of aquaculture system. Water continuously flows through concrete troughs or tanks - fresh water enters the system and remains in the holding tank area until discharged when the water quality has declined. The constant water flow can occur by natural means through the diversion of rivers or streams, or it can be pumped from wells.
  • Hydroponics: A method of raising plants in nutrient-rich water, rather than soil. A polyculture operation can be set up in conjunction with a hydroponic system in which plants feed off of the nutrients contained in fish wastes.
  • Netpen system: An aquaculture system that consists of mesh enclosures (or sometimes cages), typically placed in coastal areas. The outside structures may be rigid or semi-rigid. The system design relies upon dilution as the solution to pollution. There is no effective barrier between the netpen interior and the ocean. Wastes are emitted directly into the surrounding waters. The system design also creates the potential for farmed individuals to escape into the wild.
  • Ocean ranching: Release of farm-raised juveniles into the wild to supplement wild fisheries. The release of the captive-reared individuals is common in areas where stocks of fish are depleted due to overfishing, habitat destruction or pollution. The term ranching is also used to refer to the aquaculture practice of capturing juvenile fish from the wild and rearing them in cages. The fish are kept in cages and are fattened up until harvested at their optimal size and weight. This practice is common in Australia and the Mediterranean with bluefin tuna.
  • Organic aquaculture: An aquaculture system in which food production is managed as an integrated, whole system where all individual parts are meshed together. All parts of the operation are connected to each other: the nutrient inputs, the animals, the environment, and the wastes. The use of antibiotics, genetically engineered organisms, or animal products in the feed is prohibited under most organic culture system standards.
  • Polyculture: The raising of two or more species in the same aquaculture system. It may involve animals, plants, or plants and animals together. One example would be that of rearing of fish within rice paddies, a common type of polyculture practiced in China. The fish keep mollusks and insects in check - these organisms can cause damage to the rice. The fish can also stir up soil nutrients and make them available to the plants.
  • Pond system: One of the earliest types of aquaculture to be practiced. Ponds can either be natural or artificially constructed. They are usually shallow, with sides that are not too steep in order to prevent erosion. Tilapia, catfish, and carp are most commonly cultured in ponds.
  • Recirculating system: Recirculating systems are closed, or semi-closed, systems in which most, or all, of the water is recirculated throughout the system and very little is discharged. Water that would otherwise be discharged as wastes is treated and recirculated for re-use within the system.

Commonly Farmed Species

  • Carp: Carp was one of the first types of fish to be grown in aquaculture systems. In particular, the common carp has been cultured throughout the world. Adult carp tend to be omnivorous, feeding on snails, mollusks, worms, algae, aquatic plants, seeds and detritus and can be reared in inland-based earthen ponds, cage culture, or polyculture systems. They have been incorporated into rice paddies to feed on the insects and other organisms associated with rice culture. Carp are a rapidly growing fish and are able to tolerate less than ideal environmental conditions. They can, however, become a nuisance when cultivated in a non-indigenous area, as has recently been seen in the southern United States following accidental escapes of several kinds of carp from aquaculture facilities in the early 1990s.
  • Catfish: Channel catfish are a freshwater species native to North America. They are primarily vegetarian, thus not reliant upon fishmeal (their feed is grain-based but may contain small amounts of fishmeal). They are typically cultured in earthen ponds.
  • Clams: Clams belong to the mollusk family and are filter feeders, feeding mainly on algae. The type of culture for clams differs according to species. Included among clam species are hardshell clams, surf clams, softshell clams, geoducks and ocean quahogs.
  • Mussels: Mussels are an important part of an aquatic ecosystem. Like clams, they too are filter feeders, and help to maintain good water quality by filtering nutrients, contaminants and sediments from the water. They have been used in polyculture systems to improve the quality of the surrounding environment. Mussels are an important indicator of ecosystem health. They may be cultured using bottom culture techniques, raft culture techniques, or rack culture.
  • Oysters: Like other mollusks, oysters are filter feeders, with the ability to filter nutrients, contaminants and sediments out of the water. Raft, rack and longline practices are well-developed methods for the cultivation of oysters.
  • Salmon: Wild salmon are naturally aggressive predators and inhabit cold-water streams, estuaries and the ocean areas. Native only to the Northern hemisphere salmon were once plentiful in various countries, though many of these wild populations are currently in serious decline. Varieties such as Pink, Coho, Sockeye and Chinook are salmonids whose wild populations are healthy. Atlantic salmon is the farmed salmonid of choice because of its hardiness and ease of farming. Salmon farming generally occurs in two phases: a freshwater phase and a marine phase. The eggs are hatched in land-based freshwater tanks, and then transferred to net pens in the ocean. It is this second stage of salmon farming that has the most damaging effects on nature. Salmon are a carnivorous species and depend on large amounts of protein in their diet, supplied to them through fishmeal, which is produced from wild-caught fish. Currently, efforts are underway to reduce farmed salmon's dependence on fishmeal as the primary source of protein.
  • Shrimp: Shrimp are one of the world's most profitable delicacies. However, the farming of shrimp causes a great amount of environmental damage. Cultured primarily in coastal areas that were once mangrove swamps, shrimp farms tend to salinate the land and render it unsuitable for future culturing in just a few short years. The shrimp culture industry is export-oriented. Cultured mainly in Asia, most shrimp exports are transported to countries such as Japan, the United States, Europe and Canada. The wild populations of shrimp are varied around the world. Some species have been depleted while others remain plentiful. The capture fisheries for shrimp also leave a large impact on the environment. Typically caught through the use of trawls, the capture of one pound of shrimp results in the capture of four to ten pounds of unwanted by-catch, which is most often discarded or left to die.
  • Striped Bass: Also known as the striper or rockfish, the striped bass is one of the most desirable recreational finfish in the country. Striped bass farming methods typically include pond systems and recirculating systems. Oftentimes, the farmed striped bass is actually a hybrid between white bass and striped bass.
  • Sturgeon: Sturgeon eggs, known commonly as caviar, are one of the world's most well recognized delicacies. Sturgeon live in rivers, coastal marine waters, and lakes in the Northern hemisphere and mature at a relatively late age, usually between 15 and 25 years, though they can live to be over 100 years old. Because of this late maturity, their populations are particularly vulnerable to overfishing. Because of declining natural populations, coupled with the continued popularity and profitability of caviar, sturgeon farming has gained more focus on the global scale.
  • Tilapia: Tilapia are native to Africa, but have been introduced and cultured in many countries around the world, and are currently one of the most widely cultured fish in the world. The species most commonly cultured are the blue tilapia, the Nile tilapia and the Mozambique tilapia. They are suitable for culture since they can reproduce easily, are disease-resistant, are omnivorous and eat a wide variety of foods (though their preferred diet consists mainly of algae), and can tolerate various environmental conditions. The common culture practices employed for the rearing of tilapia include pond culture and flow-through tank culture.
  • Trout: Rainbow trout is the most commonly cultivated trout variety in the world because it is a hardy species and easier to cultivate than other varieties. The farming of trout is performed in earthen or concrete raceways with flowing water.