ez Aquaculture Glossary

Average Body Weight - The average weight of all targeted organisms in the measured population.

A water volume equivalent to one surface acre with a depth of one foot; equal to 325,850 gallons or approximately 2,718,000 pounds of water.

The mixing of air and water by wind action, or by air forced through water, generally refers to a process by which oxygen is added to water.

The ability of a mineral solution to neutralize hydrogen ions; usually expressed as equivalents of calcium carbonate.

The gas NH3 highly soluble in water. Ionized ammonia (NH4+) is relatively non-toxic to fish while the un-ionized form is extremely toxic. The percent of the total ammonia in the un-ionized form is a function of pH and temperature.

Also called total ammonia. The summed weight of Nitrogen in both the ionized (ammonium, NH4+) and molecular (NH3) forms of dissolved ammonia (NH4 - N plus NH3-N). Ammonia values are reported as N (the hydrogen being ignored in analyses).

The ionized form of ammonia, NH4+ .

A situation where the amount of Dissolved Oxygen in the water is reduced to zero. The end result is a localized area that is not capable of supporting biological activity.

A plate, usually constructed of concrete or steel attached around a drain pipe and extending about two feet outward. It is buried in the pond levee to retard the seepage of water through the levee along the drain pipe.

The overgrowth of algae, marine invertebrates, and other organisms on nets, intake pipes, and structures in the water. Biofouling can restrict water flow and access to oxygen and food by the growing shellfish.

Water with salt concentrations ranging between 5-15 ppt salinity and suitable for aquaculture production for certain species.

The parental breeding flock, both males and females, which are used to produce the ‘seed’ of the cultured organism (fish-fry, shrimp post-larvae, etc) for stocking the aquaculture facility

Chemical capable of taking up or giving up hydrogen ions and sustains pH within a narrow range.

A production method in which barrow pits, farm ponds, or lakes are used for fish production by containing the fish in cages placed in the water.

A colorless, odorless gas, CO2, resulting from the oxidation of carbon-containing substances; highly soluble in water. Toxic to fish at high levels. Toxicity to fish increases at low levels of oxygen. May be used as an anesthetic.

The population, number, or weight of a species that a given environment can support.

Species, such as catfish, which spawn in a cavity along the bank of a pond. In commercial aquaculture a container such as a milk can is substituted.

Generally, fish that spawn in water temperatures below 55°F. The main cultured species are trout and salmon. See Cool water Species; Warm Water Species.

Generally, fish that spawn in temperatures between 40° and 60° F. The main cultured cool water species are muskellunge, sauger, walleye, and yellow perch. See Cold water Species; Warm Water Species.

A marketing unit of measurement equal to number per pound. For example, a 20 count would be the same as 20 per pound.

A situation where a dense population of an organism, e.g. a bloom of phytoplankton, depletes the resources from their immediate environment that are necessary to support their life processes. This results in the population, as a whole, dying within a short time interval.

Flow rate equal to 449 gallons per minute.

Removal of the residual hypochlorite or chloramine from water to allow its use in fish culture. Charcoal is used frequently because it removes much of the hypochlorite and fluoride. Charcoal is inadequate for removing chloramine.

A chemical process that is mediated by bacteria in the sediment and that converts organic Nitrogen (in the form of ammonia, nitrite, and nitrate) to elemental Nitrogen (in the form of Nitrogen gas).

A disease pathogen that is capable of infecting its host organism directly from a previous host of the same species.

In the aquatic environment , the life supporting gas – oxygen – is present dissolved in solution with the water and must be extracted from the water by living organisms using specialized respiratory structures, such as gills. If the level of Dissolved Oxygen drops too low, then respiratory distress leading to death may occur.

The residue of all dissolved materials when all water is evaporated.

Aquaculture system that is designed and operated on a sustainable basis, minimizing long-term environmental impact.

An environmental condition where excess nutrients, in the form of Nitrogen, are introduced into a water body leading to increase growth of micro and macroalgae.

The stage in a fish's life between 1 inch and the length at which it is restocked for grow-out to market size.

The volume of water moving past a given point in a unit of time, usually expressed as cubic feet per second (cfs) or gallons per minute (gpm).

A ratio of food intake to body weight gain; more generally, the total weight of all feed fed to a lot of fish divided by the total weight gain of the fish lot. The units of weight and the time interval over which they are measured must be the same. The better the conversion, the lower the ratio.

Water containing less than 0.05% total dissolved salts by weight.

Fish larvae upon hatching from eggs.

The process of sorting fish by size, usually with some sort of screen or cage.

An acronym for the phrase "Generally Recognized As Safe" under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act.

Added biomass per unit time, measured as gram per day. The value varies as a function of fish species, fish size, culture conditions and feed.

The ability of water to neutralize soap, due to the presence of Cations such as calcium and magnesium; usually expressed as parts per million equivalents of calcium carbonate. Refers to the calcium and magnesium ion concentration in water on a scale of very soft (0-20 ppm as CaCO3), soft (20-50 ppm), hard (50-500 ppm) and very hard (55+ ppm).

The aquaculture production stage in which crop organism hatches from eggs and grows to stocking size.

An odorous, soluble gas, H2S, resulting from anaerobic decomposition of sulfur-containing compounds, especially proteins.

A situation where excess nutrients, primarily Nitrogen, are introduced into the aquatic environment resulting in eutrophication.

A situation where the amount of Dissolved Oxygen in the water is reduced to a level significantly lower than its theoretical maximum resulting in induced stress in aquatic organisms due to lack of oxygen for normal metabolism.

Period from fertilization of the egg until it hatches.

A disease pathogen that is not capable of infecting its host organism directly from a previous host of the same species but rather it must pass through an alternate host before becoming infective to the target organism.

Those aquatic organisms that exist buried in the sediment as opposed to those that live at the sediment surface or in the water column.

Aquaculture production strategies, differing in stocking densities and yield potential, according to the Production Capacities of the production systems.

Rearing of fish at densities greater than can be supported in the natural environment; utilizes high water flow or exchange rates, aeration, and requires the feeding of formulated feeds.

Fish less than one year old. Also refers to fingerlings.

Crops require mineral elements from the soil (such as calcium, magnesium, Nitrogen, phosphorus, potassium), hydrogen and oxygen from water, and carbon from CO2 in the air.

Calcium Oxide, Quicklime, or Burnt Lime used as a disinfectant for fish-holding facilities (produces heat and extreme alkaline conditions). Agriculture lime is used to increase the alkalinity of water in pond settings. Sodium bicarbonate is used to increase the alkalinity in water recirculating systems.

A form of oxygen cooled to a liquid state and used commonly in recirculating aquaculture systems because it is cheaper per unit than gaseous oxygen.

The rate at which a population or organisms are dying due to adverse environmental conditions, a disease situation or some other stress impacting the population.

A practice where very small fish are held under conditions that promote growth while protecting them from predators and other environmental hazards.

A variety of chemical compounds that are necessary to promote growth of plants and animals. In the marine environment, the most common nutrient that is limiting for plant growth is Nitrogen in the form of nitrate (NO3-).

A disease-causing organism that cannot live in the marine environment on its own and must reside in the host tissue to survive.

Aquaculture production procedures which maximize natural processes and avoiding artificial, made inputs.

A condition, normally occurring at night, in which oxygen dissolved in pond water has been depleted mainly because of the decomposition of organic matter and respiration of organisms in the pond.

A situation where a disease organism is commonly found in the local environment and presence of the disease in local populations of the host organism is routinely observed.

Any type of biological entity that causes disease through infecting a host organism.

Fish elevator used for harvesting live fish from pond harvesting pit, to Fish Sorting Machine or Fish Transfer Tanks.

An expression of the acid-base relationship designated as the logarithm of the reciprocal of the hydrogen-ion activity; the value of 7.0 expresses neutral solutions; values decreasing below 7.0 represent increasingly acidic solutions; values increasing about 7.0 represent increasingly basic solution.

Microscopic plants suspended in water with little or no capability for controlling their position in the water mass; frequently referred to as algae.

The various, mostly microscopic, aquatic organisms (plants and animals) that serve as food for larger aquatic animals.

The ability of fish to take on approximately the same body temperature as the ambient temperature of their environment. Also referred to as cold-blooded.

A food production system, which grows several species simultaneously in the same space. In aquaculture, growing multiple aquatic organisms in the same water body.

The biological interactions occurring between different organism populations developing within the aquaculture ponds. In open aquaculture systems, this usually includes water organisms: primary producers (algae), secondary producers (zooplankton) and bottom populations which include bacterial populations and higher organisms.

The building structure that houses the processing equipment and auxiliary systems, used in the fish Processing Plant, for the purpose of preparing fish portions prior to marketing. Processing equipment include machines for cleaning, sorting, scaling, eviscerating, filleting, trimming, cooling or freezing and packing fish and fish portions, prior to marketing.

An aquaculture system in which the culture media is continuously re-used, by its recirculation through biological and mechanical filters, which remove the organic matter and nitrogenous wastes

The utilization of oxygen in the breakdown of carbohydrates and releases carbon dioxide and water as by-products.

A measurement of the amount of salt that is dissolved in water and is normally reported in parts per thousand (ppt). Normal seawater has a salinity of 30-35 ppt.

Farms that concentrate on partial production mainly the grow-out phase, from nursed fingerling to market-size. Satellite Farms are associated with a Central Farm, which produces the seed-fry and/or post larvae and the processing, packaging and marketing.

Nets used to harvest fish from ponds. Seines are usually 25% longer than the width of the pond and have a depth 25% deeper than the maximum depth of the pond.

A chemical compound (NaHCO3) used as a buffer in recirculating aquaculture systems.

Act of obtaining eggs from female fish and sperm from male fish.

Adding the fish population into the pond or tank, to initiate the production cycle.

Any condition that forces an organism to expend more energy to maintain stability.

Species of animals which spawn on substrate such as gravel, rock, perlon mats, or other material.

A group of freshwater fish species belonging to the family Cichlidae, native of Africa and the Middle East, including three genera: Oreochromis, Sarotherodon, and Tilapia. The most commonly used commercial strains are Oreochromis niloticus and Oreochromis aureaus. Tilapia is an omnivore. In advanced commercial aquaculture systems tilapia feeds on regular or extruded pellets 22-25% protein. The main commodity feed ingredients include: Soy, Corn, Wheat middling, Cottonseed mill, fishmeal, meat meal and others.

A measurement of the total ammonia that occurs in water. Chemically, these two forms are represented as NH4+ and NH3. NH3, unionized ammonia (abbreviated as UIA), is the form which is toxic to fish. Water temperature and pH will effect which form of ammonia is predominant at any given time in an aquatic system.

All of the solids in the water, including dissolved, suspended, and settleable components.

A relative measure of the ability of a chemical to be toxic. Usually refers to the ability of a substance to kill or cause an adverse effect. High toxicity means that small amounts are capable of causing death or ill health.

Presence of suspended or colloidal matter or planktonic organisms that reduces light penetration of water.

A nitrogenous waste product of mammals containing two Nitrogen ions.

Essential nutritive factors required in small amounts for the regulation of metabolism.

Generally, fish that spawn at temperatures above 60°F. The chief cultured warm water species are basses, sunfish, catfish, and minnows. See Cold Water Species; Cool Water Species.

As it relates to fish nutrition and general fish health, involves dissolved minerals, gases, suspended, and settleable solids found in fresh water.

A virus found in wild and farmed crustaceans, such as: shrimp. The disease resulting from WSSV is lethal to shrimp and highly virulent. Transmission of the virus often occurs through ingestion of diseased tissue or cohabitation with virus carriers. The virus is killed by cooking and does not pose danger to humans.

A class of naturally occurring yellow and orange plant pigments added to fish feeds to enhance the color of skin pigments or muscle. In white flesh fish, xanthophylls impart an undesirable yellow color.

A component of fish feed, especially for larvae feeding used for its high protein content.

Minute animals in water, chiefly rotifers and crustaceans, that depend upon water movement to carry them about, having only weak capabilities for movement. They are important prey for young fish.