Part Per Thousand (ppt)

A concentration at which one unit is contained in a total of one thousand units. Seawater (35 ppt) is normally expressed in ppt.


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.


The formation of carbohydrates from carbon dioxide and water that takes place in the chlorophyll-containing tissues of plants exposed to light; oxygen is produced as a by-product.


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


Aquaculture practice involving finned fish.


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 closed production system in which excavated soil is used to build levees and provide a gradual bottom slope.

Pond acreage

Area committed to extensive aquaculture holdings at a fish farm or company.

Pond Levee

The wall of a pond which is constructed to hold in the water.

Potamodromous fish

Migratory fish that move within fresh water only.

Predacious Fish

A fish species that eats other fish.