Glossary of Aquaculture Terms
Aeration – To supply with air or expose to air circulation. Typically used to increase
dissolved oxygen (D0).
Alkalinity – Also called “buffering capacity.” Measured as mg/L CaCO3 it is the ability of a
solution to resist changes in pH, which can stress fish. Buffers (carbonates and bicarbonates
in water) absorb excess acids and bases. In most aquaculture systems alkalinity should be
maintained above 50 mg/L
Anesthetic – Chemical approved and used for handling fish to reduce activity and
vulnerability to damage.
Aquarium Trade Fish – Also known as “ornamental fish.” Fish species (e.g. koi, goldfish,
guppies) typically reared by hobbyists in small ponds or small RASs. These fish are raised
primarily for aesthetics.
Aquifer – Underground bed or layer yielding ground water for wells and springs etc.
Artesian Well – A well drilled through a water impermeable strata into strata that receive
water from a higher altitude so that pressure forces water to flow upward.
Bacteria – Any of the unicellular prokaryotic microorganisms of the class Schizomycetes,
which vary in morphology, oxygen and nutritional requirements, and motility. They may be
free-living, saprophytic, or pathogenic in plants or animals.
Biofilter – Component of RAS system which houses beneficial bacteria to assist in the
Biological Oxygen Demand (BOD) – The amount of oxygen required by aerobic
microorganisms to decompose the organic matter in a sample of water.
Cage Culture – The practice of raising fish in supported, relatively small enclosures of
plastic mesh that are anchored in a body of water. Cage culture provides easier access to fish
when feeding, sampling, and harvesting; and also facilitates use of waters otherwise
unsuitable to aquaculture such as rivers, lakes, and ponds with irregular bottoms.
Chemical Oxygen Demand (COD) – the amount of oxygen consumed by a liter of
solution: a measure of the amount of organic compounds in water.
Colloid – A suspension of finely divided particles in a continuous medium from which the
particles do not settle out rapidly and are not readily filtered.
Constructed Wetland – Man-made habitat used to facilitate the cleansing of wastewater
before its reintroduction to local watersheds. Plants routinely serve as primary filters and
secondary trickling beds; although other organisms such as bivalve mollusks, crayfish and
annelids can also rejuvenate water by removing suspended solids.
Culturist – A fish farmer.
Deterrent Method – Any process implemented to keep predators away from fish stocks
Dissolved Oxygen (DO) – Level of oxygen in water and available for living organisms.
Measured as mg/l, ppm, or percent saturation.
Drug – A substance used in the diagnosis, treatment, or prevention of a disease
Flocculant - A chemical that causes suspended particles in liquids to aggregate and then
participate because of their accumulated mass. They are used to improve the sedimentation
in water, reducing cloudiness.
Groundwater – Subsurface water which supplies wells and springs.
HACCP – (Hazard Analysis and Critical Control Points) – A management system that
identifies, evaluates and controls hazards that are significant for food safety.
Oxygenation – The act of adding supplemental oxygen to a body of water, in contrast to
aeration when atmospheric air is used to add oxygen to water.
Parasites – Organisms that uses another organism as a host for an unspecified length of
pH – A measure of the concentration of hydrogen ions present in a body of water indicating
acidity. Measured on a scale from 1 to 10; 7 is neutral.
Pond Culture – The raising of fish in small bodies of static water.
Predator – Any animal preying on or possessing a threat to stocks.
Raceway – Culture system which typically uses gravity to move water through system. The
inlet is located higher than the outlet and the base of these typically rectangular units that
slopes downward, supplying a rapid flow of water.
Recirculating Aquaculture System (RAS) – A sophisticated fish rearing system which
reuses water and utilizes less than 10% replacement water daily. Systems typically include a
fish holding unit, sediment removal system, biological filter, aeration or oxygenation, pump
and plumbing. All nutritional and environmental requirements for the species cultured are
provided by the grower.
Settling Pond – Basin of reduced flow designed to collect solid waste contained in
discharge waters from a culture system.
Turbidity – A measure of the clarity of water. Turbidity is closely related to total suspended
solids (TSS), but also includes plankton and other organisms as well as dissolved material in
Viral – of or relating to an infectious disease caused by a virus.
Water Quality – The condition of water as measured by a number of parameters including
pH, ammonia, alkalinity, etc.