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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.