Glossary


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A

Acceptable Biological Catch (ABC) - A term used by a Fishery Management Council referring to the range of allowable catch for a species or species group. It is set each year by the scientific panel within the Fishery Management Council (FMC or Council). The agency uses the ABC estimate as the basis for setting the annual total allowable catch (TAC).

Administrative Law Judge (ALJ) - When pertaining to the Magnuson-Stevens Act, an impartial hearing officer employed by the Environmental Protection Agency but used by NOAA to review notices of violation brought under the MSA.

Advisory Panel (AP) - A group of people appointed by a fisheries management agency to review information and give advice. Depending on the type of panel, members are usually not scientists, but most are familiar with the fishing industry or a particular fishery. Advisory panels are set for certain managed stocks, and not for the region as a whole.

Age Structure - A breakdown of the different age groups of a kind of fish in a population or sample.

Allocation - Distribution of the opportunity to fish among user groups or individuals. The share a user group gets is sometimes based on historic harvest amounts.

Anadromous - Fish that migrate from saltwater to spawn in fresh water, such as salmon.

Angler - A person who uses hook and line to catch fish, sometimes as only a hobby (with no intent to sell). This includes people releasing the catch.

Annual Catch Limits (ACL) - An amount set by weight of fish that may be harvested from a fishery. Sometimes equal to the Acceptable Biological Catch (ABC), but frequently there is a buffer below the ABC for ACL.

Annual Catch Entitlement (ACE) - An allocation of allowable harvests based on shares used in fisheries that are divided into sectors.

Annual Catch Target (ACT) - An amount of fish set by a Fishery Management Plan (FMP) for recreational fishers. The ACT is determined by reducing the Annual Catch Limit (ACL) by a certain amount to account for management uncertainty, thus setting a buffer. An ACT is put in place where fishing may exceed the ACL. It is based on recent harvest overages, errors in landing estimates, stock status, and whether accountability measures are used.

Annual Mortality - The percentage of fish dying in one year due to both fishing and natural causes.

Aquaculture - Raising fish or shellfish under some physical controls. Ponds, pens, tanks, or other containers may be used. Aquaculture may be on land or in nets and cages at sea, known as either marine aquaculture or mariculture. A hatchery is also considered aquaculture.

Availability - Describes whether a certain kind of fish of a certain size can be caught by a type of gear in an area.


B

B - Biomass, measured in terms of spawning capacity (in weight) or other appropriate units of production.

BMSY - Long-term average biomass that would be achieved if fishing at a constant fishing mortality rate equal to FMSY.

Bag Limit - The number and/or size of a species that a person can legally take in a day or trip. This is not always the same as a possession limit.

Barotrauma - An injury caused by the expansion of gas inside a fish from the rapid pressure decrease that may occur when a fish is retrieved from depths greater than 90 feet, although it can occur in depths of 33 feet. The fish is unable to swim back down and is vulnerable as prey.

Buffer - The difference between the Annual Catch Limit (ACL) and the Acceptable Biological Catch (ABC) used as a way to maintain sustainable fish populations in instances where fishers tend to exceed catch limits.

Bycatch - The harvest of fish or animals other than the species for which the fishing gear was set. Examples are blue crabs caught in shrimp trawls or sharks caught on a tuna longline. Bycatch is also often called incidental catch. Some bycatch is authorized to be kept for sale.

Bycatch Reduction Device (BRD) - Devices that are installed on fishing gear to reduce the take of incidental catch. Sometimes pronounced “bird.” Two types are the Gulf fisheye BRD and the Jones Davis BRD.


C

Carrying Capacity - The amount of fish that a specific habitat can support.

Catch - The total number or weight of fish captured from an area over a period of time. This includes fish that are caught but released or discarded instead of being landed. The catch may take place in an area different from where the fish are landed. Note: Catch, harvest, and landings are different terms with different meanings.

Catch Curve - A breakdown of different age groups of fish, showing the decrease in numbers of fish caught as the fish become older and less numerous or less available. Catch curves are often used to estimate total mortality.

Catch Per Unit of Effort (CPUE, C/E) - The number of fish caught based on the amount of effort used to make the catch. Typically, effort is a combination of gear type, gear size, and length of time gear is used. Catch per unit of effort is often used as a measurement of relative abundance for a particular fish.

Charter Boat - A boat available for hire, normally by a group of people (recreational fishers) for a short period of time.

Code of Federal Regulations (CFR) - The official publication of regulations issued by federal agencies.

Cohort - A group of fish spawned during a given period, usually within a year. See also, Year Class.

Commercial Fishery - A term related to the whole process of catching and marketing fish and shellfish for sale. When considered in a Fishery Management Plans (FMP) it includes fishery resources, fishers, and related businesses.

Common Property Resource - A term that indicates a resource owned by the public. It can be fish in public waters, trees on public land, or air. The government regulates the use of a common property resource to ensure its future benefits.

Council - A regional fishery management group as established by the Magnuson-Stevens Fishery Conservation and Management Act of 1976 (MSA). There are eight geographically oriented fishery management councils directed under the MSA to develop fishery policies designed to manage those species most often found in federal waters of their geographic region and in need of conservation and/or management.


D

Days-at-Sea (DAS) - An allocation system based on time on the water, rather than on the amount of fish caught.

Derby fishing - A situation where catch limits are substantially lower than demand, leading to fishing operations catching as many fish as possible as quickly as possible. This leads to artificially low prices early in a season and can also lead to high bycatch amounts.

Descending device – A weighted container or line which will lower and then release fish at a sufficient depth to avoid barotrauma.

Discard mortality – rate of death of fish discarded after catch, due to the stress or injury of being caught or being injured or eaten by predators immediately upon release. Sometimes known as discard and release mortality.


E

Economic Efficiency - In commercial fishing, the point at which the added cost of producing a unit of fish is equal to what buyers pay. Producing fewer fish would bring the cost lower than what buyers are paying. Producing more fish would raise the cost higher than what buyers are paying. Harvesting at the point of economic efficiency produces the maximum economic yield.

Economic Overfishing - A level of fish harvesting that is higher than is economically efficient; when harvesting more fish becomes too expensive to attain maximum profit.

Ecosystem Component Species - Species that are not purposefully fished or managed under a Fishery Management Plan (FMP).

Effort - The amount of time and fishing power used to harvest fish. Fishing power includes gear size, boat size, and horsepower.

Endangered Species Act (ESA) - A conservation law (16 U.S.C. §§ 1531 et seq.) under which species at risk of becoming extinct are listed by the U.S. Fish and Wildlife Service and/or the National Marine Fisheries Service (NMFS) as either threatened or endangered, depending on the likelihood of extinction. Harming or killing listed species is a criminal or civil violation of the ESA.

Environmental Impact Statement (EIS) - A written analysis required under the National Environmental Policy Act (NEPA) where a Fishery Management Plan (FMP) (or some other proposed federal action) is likely to cause significant impacts to the environment.

Essential Fish Habitat (EFH) - Those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity as designated by a Fishery Management Council within a Fishery Management Plan.

Exclusive Economic Zone (EEZ) - All waters from the seaward boundary of coastal states out to 200 nautical miles.

Exempted Fishing Permit (EFP) - Permission from a Council, following public notice and comment, allowing specific changes to a Fishery Management Plan (FMP) on a limited scale.


F

Fecundity - The ability of fish to produce eggs, but also the rates of egg production at maturity.

Federal Register - The official daily publication of the executive branch of the federal government, including rules, proposed rules, and notices of federal agencies and organizations, and presidential proclamations and orders, as required by law.

Fishery - A term that applies to both the fish stock or the gear used to take a species or combination of species of fish.

Fishery Conservation Zone - The area from the seaward limit of state waters out to 200 miles. The term is used less often than the preferred term, “exclusive economic zone.”

Fishery-Dependent Data - Data collected from commercial or sport fishers and seafood dealers on fish or a fishery.

Fishery Ecosystem Plan (FEP) - A management plan used by the Western Pacific Fishery Management Council to accommodate the vast areas of the Pacific Ocean under its jurisdiction.

Fishery-Independent Data - Data collected on a fishery by scientists who catch the fish themselves, rather than depending on fishers and seafood dealers.

Fishery Management Council (FMC) - See Council.

Fishery Management Plan (FMP) - A plan to achieve specified management goals for a fishery designed by a Fishery Management Council (FMC or Council) and approved by the National Marine Fisheries Service (NMFS). It includes data, analyses, and management measures for a fishery and must undergo public comment and environmental review.

Fishing Effort - See Effort.

Fishing Mortality (F) - A measurement of the rate of removal of fish from a population by fishing. Fishing mortality can be reported as either annual or instantaneous rates. Annual mortality is the percentage of fish dying in one year. Instantaneous is that percentage of fish dying at any one time. The acceptable rates of fishing mortality vary from species to species.

Fork Length - The length of a fish as measured from the tip of its snout to the fork in the tail. See also Standard Length, Total Length. See Standard Length for comparison.

Fork Length



G

Growth - Usually an individual fish’s increase in length or weight with time. Also may refer to the increase in numbers of fish in a population with time.

Growth Model - A mathematical formula to describe the increase in length or weight of an individual fish with time.

Growth Overfishing - Occurs when too many smaller fish (before they reach their growth potential) are fished, inhibiting the fishery’s ability to produce its maximum poundage. Growth overfishing, by itself, does not affect the ability of a fish population to replace itself.


H

Habitat Areas of Particular Concern (HAPC) - A subset of an Essential Fish Habitat, designated based on ecological importance and impacts from human activities.

Harvest - The total number or weight of fish caught and kept from an area over a period of time. Note that landings, catch, and harvest are different.

Headboat - A fishing boat that takes recreational fishers out for a fee per person (a price per head). Different from a charter boat in that people on a headboat pay individual fees as opposed to renting a boat (and crew) for a group.


I

Incidental Catch - See Bycatch.

Incidental Take - A term under the Endangered Species Act and the Marine Mammal Protection Act (MMPA) to describe harming or killing a species protected under that law where the take is incidental to an otherwise lawful action. An incidental take is illegal unless a permit is first obtained under the Endangered Species Act (ESA) or MMPA.

Individual Fishing Quota (IFQ) - An allocation to an entity (including an individual or a company) giving that entity rights to catch a certain amount of fish within a certain period of time. Sometimes referred to as an Individual Transferable Quota (ITQ). It is a share of the total allowable catch (TAC).

Industrial Fishery - A fishery of species not directly used for human food. An example is menhaden.

Instantaneous Mortality - The percentage of fish dying at any one time. May be calculated for natural mortality, fishing mortality, or both.


J

Juvenile - A young fish or animal that has not reached sexual maturity.


L

Landings - The number or weight of fish unloaded at a dock by commercial fishers or brought to shore by recreational fishers for personal use. Typically, less weight than catches, as many fish are processed at sea. Landings are reported at points where fish are brought to shore. Note that landings, catch, and harvest define different things.

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.

License - A document giving the holder the right to operate in a fishery according to the terms established by the regulatory authority. Also known as a permit. Some licenses can be sold or passed on to heirs, known as a transferrable license.

License Limitation - A method of restricting the number of commercial fishers licensed to fish. Used by a Fishery Management Council (FMC or Council) as a means of limited entry..

Limited Entry - The opposite of an open access fishery. It restricts the common resource like fish by dividing allocations by issuing permits or licenses, or by establishing Individual Fishing Quota (IFQ) or Individual Transferable Quota (ITQ) that restrict harvests per trip, season, or annually.


M

M - Natural mortality of a stock. Used to assess fishery health.

Magnuson-Stevens Fishery Conservation and Management Act (MSA) - The 1976 federal law (16 U.S.C. §§ 1801 et seq.) authorizing the federal government to manage fisheries in the Exclusive Economic Zone (EEZ). Also known as the Magnuson-Stevens Act after its chief sponsors, Senator Warren G. Magnuson of Washington and Senator Ted Stevens of Alaska. Two significant amendments to the MSA occurred the Sustainable Fisheries Act of 1996, and in 2007, the Magnuson-Stevens Fishery Conservation and Management Reauthorization Act of 2006.

Management Uncertainty - A term used by the National Oceanic and Atmospheric Administration (NOAA) to explain why catch limits are set below justifiable levels. In some cases the term is used because actual landings are believed to be greater than reported landings.

Marine Mammals - Warm-blooded animals that live in marine waters and breathe air directly. These include porpoises, whales, manatees, and seals.

Marine Mammal Protection Act (MMPA) - A conservation law (16 U.S.C. §§ 1371 et seq.) protecting all marine mammals from “takes,” and providing penalties for harming or killing the mammals without permission, even if unintentional and incidental to an authorized activity.

Marine Protected Area (MPA) - Any area of the marine environment reserved by federal, state, territorial, tribal, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein (Executive Order No. 13158.) See also, Marine Reserve.

Marine Reserve - A type of Marine Protected Area with the highest restrictions on use. Sometimes referred to as “no take areas” because hunting, fishing, and collecting may be prohibited.

Maximum Fishing Mortality Threshold (MFMT) - A criteria for determining whether overfishing is occurring. MFMT is based on fishing mortality corresponding to the maximum sustainable yield. Where fishing mortality exceeds maximum sustainable yield (MSY), overfishing is occurring.

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 by a Fishery Management Council for a fishery.

Minimum Stock Size Threshold (MSST) - The greater of (a) 1/2 BMSY, or (b) the minimum stock size at which rebuilding to BMSY will occur within 10 years of fishing at the MFMT. Used to calculate rebuilding an overfished stock.

Model - A replication of a natural phenomenon that cannot be directly observed. Often a set of equations and data used to make estimates.


N

National Observer Program - A NMFS-sponsored program where independent onboard observers collect data on fishing practices, including bycatch and gear usage, to support scientific research and sustainable management of the nation’s fisheries.

National Marine Fisheries Service (NMFS) - A NMFS-sponsored program where independent onboard observers collect data on fishing practices, including bycatch and gear usage, to support scientific research and sustainable management of the nation’s fisheries.

National Oceanic and Atmospheric Administration (NOAA) - The administrative agency within the Department of Commerce that oversees the National Marine Fisheries Service (NMFS).

National Standards - Ten standards with which every Fishery Management Plan and related regulation must be consistent as required by the Magnuson-Stevens Act (see 16 U.S.C. § 1851).

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

NOAA Fisheries - See National Marine Fisheries Service.

Notice of Permit Sanctions (NOPS) - Notice given in an enforcement action to alert the offender that as a result of violations, the permit has been modified, which frequently means it is suspended.


O

Open Access Fishery - A fishery in which any person can participate at any time.

Optimum Yield (OY) - The harvest level for a species that achieves the greatest overall benefits, including economic, social, and biological considerations. The term considers both commercial and recreational yields. Optimum yield is different from maximum sustainable yield (MSY) in that MSY considers only the biology of the species.

Overfished - A stock or stock complex “whose size is sufficiently small that a change in management practices is required in order to achieve an appropriate level and rate of rebuilding.” A stock or stock complex is considered overfished when its size falls below the minimum stock size threshold (MSST). A rebuilding plan is required for stocks that are overfished.

Overfishing - A level of fishing mortality that jeopardizes the capacity of a fishery to produce the maximum sustainable yield on a continuing basis.


P

Panel - See Advisory Panel.

Population - Fish of the same species inhabiting a specified area.

Population Dynamics - The study of fish populations and how fishing mortality, growth, recruitment, and natural mortality affect them.

Possession Limit - The number and/or size of a species that a person can legally have at any one time. Applies to commercial and recreational fishers. A possession limit generally does not apply to the wholesale market level and beyond.


Q

Quota - The maximum number or weight of fish that can be legally landed in a given time period. It can apply to the total fishery or an individual fisher’s share under an Individual Transferable Quota (ITQ) system.


R

Rebuilding - The status of a fishery that is overfished with a Fishery Management Plan developed to help it return to maximum sustainable yield (MSY). A typical rebuilding plan allows fishing to continue, but at a reduced level so that the stock will increase to the target level that supports MSY.

Recreational Fishery - Harvesting fish for personal use, fun, and challenge. Recreational fishing does not include sale of catch. For the purposes of a Fishery Management Plan, the term includes the fishery resources, fishers, and businesses providing related goods and services.

Recruit - An individual fish that has moved into a fishing-size class.

Recruitment - A measure of the number of fish that enter a class during some time period, such as the spawning class or fishing-size class.

Recruitment Overfishing - When fishing pressure is too heavy to allow a fish population to replace itself (there are not enough new recruits to replace the harvested fish).

Reef Fish Complex - A term used by the Gulf of Mexico Fishery Management Council to describe the many species of fish found around natural reefs, artificial reefs, ledges, and mud lumps. Snapper, grouper, and tilefish are examples of species encompassed by this term.

Regulatory Impact Review - The part of a Fishery Management Plan that describes impacts resulting from the plan, as required by Executive Order 12866.

Relative Abundance - An index of fish population abundance used to compare fish populations from year to year. This does not measure the actual numbers of fish, but shows changes in the population over time.


S

Sea Turtle Disentanglement Network (STDN) - A volunteer program coordinated by National Marine Fisheries Service (NMFS) to report sea turtle entanglements, especially in discarded fishing gear. Volunteers include anybody who reports an incident.

Secretary - The Secretary of the Department of Commerce.

Scientific Assessment Panel - A group of biologist, economists, and sociologists put together by a federal fishery management council to review scientific data on the condition of a stock of fish and the interests of the fishers and seafood processors who use the stock. Panel members generally come from universities, and state and federal fisheries agencies.

Secretarial Management Plan - A term used to describe a plan developed by the Secretary of the U.S. Department of Commerce in response to an emergency, a Fishery Management Council’s failure to act, or for highly migratory species.

Size Distribution - A breakdown of the number of fish of various sizes in a sample or catch. The sizes can be in length or weight. This is most often shown on a chart.

Shellfish - General term for crustaceans and mollusks.

Social Impacts - The changes in people, families, and communities resulting from a fishery management decision.

Socioeconomics - A word used to identify human and economic factors in fishery management decisions. For example, how surplus income is distributed between small and large boats or part-time and full-time fishers.

Spawner-Recruit Relationship - The concept that the number of young fish (recruits) entering a population is related to the number of parent fish (spawners).

Spawning Potential Ratio (SPR) - The number of eggs that could be produced by an average recruit in a fished stock divided by the number of eggs that could be produced by an average recruit in an unfished stock. SPR can also be expressed as the spawning stock biomass per recruit (SSBR) of a fished stock divided by the SSBR of the stock before it was fished.

Spawning Stock Biomass - The total weight of the fish in a stock that are old enough to spawn.

Spawning Stock Biomass Per Recruit (SSBR) - The spawning stock biomass divided by the number of recruits to the stock or how much spawning biomass an average recruit would be expected to produce.

Species - A group of similar fish that can freely interbreed.

Standard Length - The length of a fish as measured from the tip of the snout to the hidden base of the tail fin rays. See Fork Length for comparison.

Stock - A grouping of fish usually based on genetic relationship, geographic distribution, and movement patterns. Also, a managed unit of fish.

Stock Assessment Panel - A group of scientists, skilled in the study of fish population dynamics put together by a Fishery Management Council to review the scientific data on the condition of a stock of fish. The scientists generally come from universities and state and federal fisheries agencies.

Stock Assessment and Fishery Evaluation Report (SAFE) - A report that provides a summary of the most recent biological condition of a stock of fish and the economic and social condition of the recreational fishers, commercial fishers, and seafood processors who use the fish. Councils use the report to help determine harvest levels.

Stock-Recruit Relationship - See Spawner-Recruit Relationship.

Stressed Area - An area in which there is special concern regarding harvest, perhaps because the fish are small or because harvesters are in conflict.

Summary Settlement Ticket - An enforcement tool used by the National Marine Fisheries Service to allow a violator to pay a reduced penalty for a violation in exchange for not contesting the violation in an administrative hearing.

Surplus Production Model - A model that estimates the catch in a given year and the change in stock size. The stock size could increase or decrease depending on new recruits and natural mortality. A surplus production model estimates the natural increase in fish weight or the sustainable yield.

Survival Rate - The number of fish alive after a specified time, divided by the number alive at the beginning of the period.

Sustainable Fisheries Act (SFA) - The Act passed in 1996 which reauthorized and amended the Magnuson-Stevens Act.


T

Take - In context, a term used under the Endangered Species Act or the Marine Mammal Protection Act indicating an action where a protected species was harmed or killed.

Territorial Sea - The area from average low-water mark on the shore out to three miles for the states of Louisiana, Alabama, and Mississippi, and out to nine miles for Texas and the west coast of Florida. In some cases where the shore is not the baseline, the outer limit can extend further than three miles.

Total Allowable Catch (TAC) - The annual recommended catch for a species or species group. The regional council sets the TAC from the range of the acceptable biological catch.

Total Length - The length of a fish as measured from the tip of the snout to the tip of the tail.

Total Mortality (Z) - A measurement of the rate of removal of fish from a population by both fishing and natural causes. Total mortality can be reported as either annual or instantaneous. Annual mortality is the percentage of fish dying in one year. Instantaneous mortality is that percentage of fish dying at any one time. The rate of total mortality may vary from species to species.


V

Venting Tool – A sharp hollow instrument used to pierce a fish’s abdomen to release excess gases caused by barotrauma.

Virtual Population Analysis (VPA) - A type of analysis that uses the number of fish caught at various ages or lengths and an estimate of natural mortality to estimate fishing mortality in a cohort. It also provides an estimate of the number of fish in a cohort at various ages. Sometimes referred to as cohort analysis.


Y

Year Class - A term used in aging fish to identify those fish born in a year. A cohort based on age.

Yield - The production from a fishery in terms of numbers or weight.

Yield Per Recruit - A model that estimates yield in terms of weight, but more often as a percentage of the maximum yield, for various combinations of natural mortality, fishing mortality and time exposed to the fishery.


The original version of this section was based in part on work by Kenneth J. Roberts, Jerald W. Horst, John E. Roussel, and Joseph A. Shephard, Louisiana Sea Grant College Program, Louisiana State University, as well as the NOAA Fisheries Glossary. As part of the 2020 revision, only terms used in the Guide are defined and many definitions are revised.


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