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The terms in this glossary are taken from a number of sources, but particularly from the FAO Technical Guidelines, No. 4, Fisheries Management and from the glossary on the home page of the FAO Fisheries Department (, which includes a large number of other fisheries terms.

Agenda 21

A comprehensive plan of action to be taken globally, nationally and locally by organizations of the United Nations system, governments, and major groups in every area in which human impacts on the environment. Agenda 21, the Rio Declaration on Environment and Development, and the Statement of Principles for the Sustainable Management of Forests were adopted by more than 178 Governments at the United Nations Conference on Environment and Development (UNCED) held in Rio de Janeiro, Brazil (3–14 June 1992).

biological diversity or biodiversity

The variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems. Diversity indices are measures of richness (the number of species in a system); and to some extent, evenness (variances of species’ local abundance). They are therefore indifferent to species substitutions, which, however, may reflect ecosystem stresses (such as those due to high fishing intensity).

broad fishery objective

Statement of what harvesting a particular resource attempts to achieve in terms of the fish resources and in terms of ecological, economic and social objectives.


Species taken in a fishery targeting that is targeting on other species or on a different size range of the same species. That part of the by-catch no economic value is discarded and returned to the sea, usually dead or dying.


See fishing capacity

critical habitat

Fisheries habitat necessary for the production of a given fishery resource. May be critical nursery habitat (e.g. mangroves and seagrasses) or critical spawning habitat (e.g. particular geographic location in the ocean where fish aggregate to spawn).


The components of a fish stock that are thrown back into the habitat after capture. Normally, most of the discards can be assumed not to survive.


An organizational unit consisting of an aggregation of plants, animals (including humans) and micro-organisms, along with the non-living components of the environment.

ecosystem health

A measure of ecosystem resilience (ability to maintain its structure and pattern of behaviour in the presence of stress), organization (number and diversity of interactions between ecosystem components) and vigour (a measure of activity, metabolism or primary productivity). A healthy ecosystem to maintain its structure (organization) and function (vigour) over time in face of external stress (resilience).

ecosystem integrity

The ability of an ecosystem to support and maintain a balanced, harmonious, adaptive biological community that demonstrates species composition, diversity and functional organization comparable to that of natural habitat in the region.

ecosystem productivity

The rate at which material is produced by an ecosystem over a specified period. In a strict sense, this term refers to the amount of energy fixed by plants in the system, but the term often refers to the ability of an ecosystem to produce goods and services to meet human needs.


See fishing effort

exclusive economic zone (EEZ)

A zone under national jurisdiction (up to 200 nautical miles wide) declared in line with the provisions of 1982 United Nations Convention of the Law of the Sea, within which the coastal state has the right to explore and exploit, and responsibilities to conserve and manage, the living and non-living resources.

fish stock (also fish/fishery resource)

The living resources in the community or population from which catches are taken in a fishery. Use of the term “fish stock” usually implies that the particular population is more or less isolated reproductively from other stocks of the same species and is thus self-sustaining. In a particular fishery, the fish stock may be one or several species of fish, but the definition is also intended to include commercial invertebrates and plants.

fisheries management organizations or arrangements

The institutions responsible for fisheries management, including the formulation of the rules that govern fishing activities. The fishery management organization and its subsidiary bodies may also be responsible for all ancillary services, such as collecting information; assessing stocks; conducting monitoring, control and surveillance (MCS) and consultations with stockholders; applying and/or determining the rules access to the fishery, and for resource allocation.


The term “fishery” can refer to the sum of all fishing activities on a given resource, for example, a hake or shrimp fishery. It may also refer to the activities of a single type or style of fishing on a particular resource, for example a beach seine fishery or trawl fishery. The term is used in both senses in this document and, where necessary, the particular application is specified.

fishing capacity

The ability to take the maximum amount of fish over a period of time (year, season) by a fishing fleet that is fully utilized, given the biomass and age structure of the fish stock and the present state of the technology.

fishing effort

The total amount of fishing activity on the fishing grounds over a given period of time, often expressed for a specific gear type, e.g. number of hours trawled per day, number of hooks set per day or number of hauls of a beach seine per day. Fishing effort would frequently be measured as the product of (i) the total time spent fishing and (ii) the amount of fishing gear of a specific type used on the fishing grounds over a given unit of time. When two or more kinds of gear are used, they must be adjusted to some standard type in order to derive and estimate of total fishing effort.

fishing mortality

A technical term which refers to the proportion of the fish available being removed by fishing in a small unit of time; e.g. a fishing mortality rate of 0.2 implies that approximately 20 percent of the average population will be removed in a year due to fishing. Fishing mortality can be translated into a yearly exploitation rate (see above) expressed as a percentage, using a mathematical formula.


The total number of units of any discrete type of fishing activity using a specific resource. Hence, for example, a fleet may be all the purse seine vessels in a specific sardine fishery, or all the fishers setting nets from the shore in a tropical multispecies fishery.

fully exploited/fished

Term used to qualify a stock that is probably being neither overexploited nor under-exploited and is producing, on average, close to its MSY.

genetic diversity

The sum of the actual or potential genetic information and variation contained in the genes of living individual organisms, populations or species.

genetically modified organism (GMO)

An organism that has been modified or altered by natural processes of mutation, selection and recombination; (now chiefly) artificially manipulated in order to produce a desired characteristic, which means the manipulation of the genome of an organism by laboratory techniques, esp. by the introduction of a new or altered gene using recombinant technology (Oxford English Dictionary).

harvesting strategy

Not to be confused with a management strategy. A harvesting strategy is a plan, under input or output control, for working out how the allowable catch from a stock will be calculated each year, e.g. as a constant proportion of the estimated biomass.


The practice of discarding of a portion of a vessel’s legal catch that is considered inferior (and which could have been sold) to have a higher or larger grade of fish that brings higher prices. This practice may occur in both quota and non-quota fisheries.


A variable that can be monitored in a system, e.g. a fishery to give a measure of the state of the system at any given time. Each indicator should be linked to one or more reference points and used to track the state of the fishery in relation to those reference points.

interested party or interest group

See stakeholder

limited entry

A common management tool in which the government issues a limited number of licenses to fish, creating a use right (here, the right to participate in the fishery).

management measure

Specific controls applied in the fishery to contribute to achieving the objectives, including some or all of the technical measures (gear regulations, closed areas and time closures), input controls, output controls and user rights.

management procedure

The process of conducting fisheries management. Includes all aspects involved in fisheries management including planning, implementing, monitoring and assessment.

management strategy

The strategy adopted by the management authority to reach the operational objectives. It consists of the full set of management measures applied in that fishery.

marine protected area (MPA)

A protected marine intertidal or subtidal area, within territorial waters, EEZs or in the high seas, set aside by law or other effective means, together with the overlying water and associated flora, fauna, historical and cultural features. It provides degrees of preservation and protection for important marine biodiversity and resources; a particular habitat (e.g. a mangrove or a reef) or species, or sub-population (e.g. spawners or juveniles) depending on the degree of use permitted. The use of MPAs for scientific, educational, recreational, extractive and other purposes including fishing is strictly regulated and could be prohibited.

maximum sustainable yield (MSY)

The highest theoretical equilibrium yield that can be continuously taken (on average) from a stock under existing (average) environmental conditions without significantly affecting the reproduction process.

non-governmental organization (NGO)

Any organization that is not a part of federal, provincial, territorial or municipal government. Usually refers to non-profit organizations involved in development activities.

open access

A condition describing a fishery that is available to anyone who wants to fish.

operational objective

A specific purpose that can be achieved through the application of a management measure.


Exploited beyond the limit believed to be sustainable in the long term and beyond which there is an undesirably high risk of stock depletion and collapse. The limit may be expressed, for example, in terms of a minimum biomass or a maximum fishing mortality, beyond which the resource would be considered to be over-exploited.

performance measure

A function that relates the value of an indicator to its reference point, and that guides the evaluation of fisheries management performance in relation to its stated operational objective.

policy goal

High-level policy objective relating to fish resources, ecosystems (e.g. biodiversity), economics and social benefits, usually at a specified at regional or national level.


An overarching guiding concept for managing natural resources, usually developed in the context of global agreements and/or legislation. Examples: ‘the precautionary approach”, “maintaining ecosystem integrity”.

property rights

A legal right or interest in respect to a specific property. A type of resource ownership by an individual (individual right) a group (communal right), or the state (state property).


A share of the TAC allocated to an operating unit such as a country, a community, a vessel, a company or an individual fisherman (individual quota) depending on the system of allocation. Quotas may or may not be transferable, inheritable and tradable. While generally used to allocate total allowable catch, quotas could be used also to allocate fishing effort or biomass.

reference point

A benchmark against which to assess the performance of management in achieving an operational objective, corresponding to a state considered to be desirable (target reference point) or undesirable and requiring immediate action (limit reference point).


The release of cultured juveniles into the wild to restore the spawning biomass of severely overfished stocks to levels at which they can once again provide sustainable yields. Restocking requires managers to protect the released animals and their progeny until replenishment has occurred.

rights-based management

A fisheries management regime in which access to the fishery is controlled by use rights that may include not only the right to fish, but also specifications about any or all of the following: how fishing may be conducted (e.g. the vessel and gear); where and when fishing may take place and how much fish may be caught.

species assemblage

The term used to describe the collection of species making up any co-occurring community of organisms in a given habitat or fishing ground.


Any person or group with a legitimate interest in the conservation and management of the resources being managed. Generally speaking, the categories of interested parties will often be the same for many fisheries, and should include contrasting interests: commercial/recreational, conservation/exploitation, artisanal/industrial, fisher/buyer-processor-trader as well as governments (local/state/national). The public and the consumers could also be considered as interested parties in some circumstances.


A group of individuals in a species occupying a well-defined spatial range independent of other stocks of the same species. Random dispersal and directed migrations due to seasonal or reproductive activity can occur. Such a group can be regarded as an entity for management or assessment purposes. Some species form a single stock (e.g. southern bluefin tuna) while others are composed of several stocks (e.g. albacore tuna in the Pacific Ocean comprises separate northern and southern stocks). The impact of fishing on a species cannot be fully determined without knowledge of the stock structure.

stock enhancement

The release of cultured juveniles into the wild to yield desired levels of harvest by overcoming recruitment limitation. Stock enhancement is applied only to operational fisheries, and the additional value derived from the released animals at harvest should exceed the cost of producing the juveniles.

stock productivity

Relates to the birth, growth and death rates of a stock. A highly productive stock is characterized by high birth, growth and mortality rates, and as a consequence, a high turnover and production to biomass ratio. Such stocks can usually sustain higher exploitation rates and, if depleted, could recover more rapidly than comparatively less-productive stocks.

strategic management

Management of the fishery’s overall objectives and policy.

sustainable development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

sustainable use

The use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity, thereby maintaining its potential to meet the needs and aspirations of present and future generations.

target resource-orientated management (TROM)

A term constructed to refer to conventional fisheries management in which the stock of the target species is the main concern of management actions.

target species

Those species that are primarily sought by the fishermen in a particular fishery. The subject of directed fishing effort in a fishery. There may be primary as well as secondary target species.

territorial use rights in fishing (TURFs)

Fishery management methods that assign rights to individuals and/or groups to fish in certain locations, generally, although not necessarily, based on long-standing tradition (“customary usage”).

total allowable catch (TAC)

Total amount of resource allowed to be taken in a specified period (usually a one-year period), as defined in the management plan. TAC may be allocated to the stakeholders in the form of quotas as specific quantities or proportions.

traditional ecological knowledge

The local knowledge held by a group of indigenous people and passed from generation to generation on the nature and functioning of the ecosystem.

user rights

The rights held by fishers, fishing communities or other users to use the fishery resources.


The amount of biomass, or the number of units currently harvested.

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