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 gases surrounding the earth; consists of approximately 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and minute quantities of helium, krypton, neon, and xenon, plus water vapor.

Algae Bloom

A high density or rapid increase in abundance of algae.


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.

Ammonia Nitrogen

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+ .

Amphidromous fish

Migratory fish that live in both fresh and salt water, independent of breeding.

Anadromous fish

Migratory fish that live in salt water but breed in fresh water.

Anal Fin

The fin on the ventral median line behind the anus.

Anti-Seep Collar

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 external posterior opening of the alimentary tract; the vent.


also known as aquafarming, it is the controlled growth of aquatic species. The propagation and rearing of aquatic organisms (both marine and freshwater) in controlled or selected aquatic environments for any commercial, recreational, or public purpose. Potential purposes of aquaculture include bait production, wild stock enhancement, fish cultures for zoos and aquaria, rebuilding of populations of threatened and endangered species, and food production for human consumption.

Aquaculture Biotechnology

The use of an aquaculture organism to make a product or run a process. Different aquatic organisms, both animal and plant, are used in industry, farm animal and aquaculture feeds, medicinal treatments, wastewater treatment, and the recycling of gas products. (Maine Aquaculture Innovation Center).