NCDMF Glossary of Fisheries Terms



DMF Home	About DMF	Contact DMF	DMF Offices

Landings - The number or poundage of fish unloaded at a dock by commercial fishermen or brought to shore by recreational fishermen for personal use. Landings are reported at the points at which fish are brought to shore. Note that landings, catch, and harvest define different things.

Latent Species - A species of fish that has the potential to support a directed fishery.

Length Frequency - A breakdown of the different lengths of a kind of fish in a population or sample.

Length-Weight Relationship - Mathematical formula for the weight of a fish in terms of its length. When only one is known, the scientist can use this formula to determine the other.

Limited Entry - A program that changes a common property resource like fish into private property for individual fishermen. License limitation and the individual transferable quota (ITQ) are two forms of limited entry.

mm - See millimeter.

M - See natural mortality.

MEY - See maximum economic yield.

MRFSS - See marine recreational fishery statistics survey.

Magnuson Act - See Fishery Conservation and Management Act.

Mariculture - The raising of marine finfish or shellfish under some controls. Ponds, pens, tanks, or other containers may be used, and feed is often used. A hatchery is also mariculture but the fish are released before harvest size is reached.

Marine Mammal - Animals that live in marine waters and breathe air directly. These include porpoises, whales and seals.

Marine Recreational Fishery Statistics Survey (MRFSS) - An annual survey by the National Marine Fisheries Service (NMFS) to estimate the number, catch, and effort of recreational fishermen. It serves as a basis for many parts of fisheries management plans.

Mark-Recapture - The tagging and releasing of fish to be recaptured later in their life cycles. These studies are used to study fish movement, migration, mortality, and growth, and to estimate population size.

Maximum Economic Yield (MEY) - This is the total amount of profit that could be earned from a fishery if it were owned by an individual. An open entry policy usually results in so many fishermen that profit higher than opportunity cost is zero. See economic rent.

Maximum Sustainable Yield (MSY) - The largest average catch that can be taken continuously (sustained) from a stock under average environmental conditions. This is often used as a management goal.

Mean - Another word for the average of a set of numbers. Simply add up the individual numbers and then divide by the number of items.

Meristics - A series of measurements on a fish, such as scale counts, which are used to separate different populations or races of fish.

Millimeter (mm) - Metric measurement of length 1/25 of an inch long.

Model - In fisheries science, a description of something that cannot be directly observed. Often a set of equations and data used to make estimates.

Mollusk - A group of freshwater and saltwater animals with no skeleton and usually one or two hard shells made of calcium carbonate. Includes the oyster, clam, mussel, snail, conch, scallop, squid, and octopus.

Morphometrics - The physical features of fish, for example, coloration. Morphometric differences are sometimes used to identify separate fish populations.

Multiplier - A number used to multiply a dollar amount to get an estimate of economic impact. It is a way of identifying impacts beyond the original expenditure. It can also be used with respect to income and employment.

NMFS - See National Marine Fisheries Service

National Marine Fisheries Service (NMFS) - A federal agency - with scientists, research vessels, and a data collection system - responsible for managing the nation’s saltwater fish. It oversees the actions of the Councils under the Fishery Conservation and Management Act.

National Standards - The Fishery Conservation and Management Act requires that a fishery management plan and its regulations meet seven standards. The seven standards were developed to identify the nation’s interest in fish management.

Natural Mortality (M) - A measurement of the rate of removal of fish from a population from natural causes. Natural morality can be reported as either annual or instantaneous. Annual mortality is the percentage of this fish dying in one year. Instantaneous is the percentage of fish dying at any one time. The rates of natural mortality may vary from species to species.

Nursery - The part of a fish’s or animal’s habitat where the young grow up.

Back to the glossary Index.