Glossary

Abiotic
A nonliving (physical or chemical) component of the environment.

Absolute Abundance
The total number of a kind of fish in a population; this is rarely known, and usually estimated from the relative abundance. (see Abundance Index)

Abundance Index
A relative measure of the weight or number of fish in a stock, a segment of the stock (e.g. the spawners), or an area. Often available in time series, the information is collected through scientific surveys or inferred from fishery data.

Abyssal Plain
The ocean floor offshore from the continental margin, usually very flat with a slight slope.

Abyssalpelagic Zone
The pelagic environment from a depth of approximately 4,000 meters to 7,000 meters.

Abyssal Zone
The bottom from a depth of approximately 4,000 meters to 7,000 meters.

Acceptable Biological Catch (ABC)
A scientific calculation of the sustainable harvest level for a species or species group, and is used to set the upper limit on the range of potential annual total allowable catch (TAC). (see Allowable Biological Catch)

Accuracy
Of an estimate: an indicator of the closeness of an estimated value (e.g. population parameter) to the actual value. It should not be confused with precision, which relates to the confidence limits (variability) of the estimate and can always be computed from the samples. (see Precision)

Acoustic Survey
A systematic method of gathering information on fish availability and abundance in a water body with the help of sophisticated acoustic instruments, such as echo sounders and sonar, that generate ultrasonic sound for the detection of fish.

Adaptive Management
1. A management process involving step-wise evolution of a flexible management system in response to feedback information actively collected to check or test its performance (in biological, social, and economic terms). It may involve deliberate intervention to test the fishery system's response; 2. The process of improving management effectiveness by learning from the results of carefully designed decisions or experiments.

Advisory Panel (AP)
Provides additional review and stakeholder perspective to a regional fishery management council (FMC) for proposed actions and draft amendments to fishery management plans (FMPs). The advisory panel usually represents a variety of interests from commercial, recreational, environmental, and consumer areas. However, panel members do not have seats on the council and do not vote. (see Scientific and Statistical Committee)

Age
The number of years of life completed, here indicated by an Arabic numeral, followed by a plus sign if there is any possibility of ambiguity (age 1, age 1+).

Age Class
A group of individuals of the same age range in a population. The age 0 group are the fish in their first year of life. A fish born in April of a given year remains in the age 0 group until April of the following year. The term usually refers to a year class in long-lived annually breeding species, but shorter units of time are also used, particularly in the tropics.

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

Age-Length Key
One approach used to assign ages to fish, given length measurements. Used to convert catch-at-size data into catch-at-age data. The keys specify the probability that fish of a given size belong to one of several age groups. (see Length-Weight Relationship)

Alaska Pollock
Scientific name: Theragra chalcogramma; Market names: Pollock, Alaska Pollock; Vernacular names: Whiting, Pacific tomcod, Pacific pollock, Alaska pollock

Alaska Snow Crab
Scientific name: Chionoecetes opilio; Market name: Snow crab; Vernacular name: Opilio, Opies

Albacore Tuna
Scientific name: Thunnus alalunga; Market name: Tuna; Vernacular names: Germon, Longfinned Tuna, Longfinned Albacore, Albecor, T. Gero

Allowable Biological Catch (ABC)
A term that refers to the range of estimated allowable catch for a species of species group. It is set each year by a scientific group. The ABC estimates are used to set the annual total allowable catch (TAC). (see Acceptable Biological Catch)

Allocation
1. Distribution of the opportunity to fish among user groups or individuals. The share a user group gets is sometimes based on historic harvest amounts; 2. A quantity of catch, effort, or biomass attributed to a person, a vessel, and a fishing company. The allocation can be absolute (e.g. a number of tons) or relative (e.g. a percentage of the annual allowable catch).

Alternatives
In the context of an environmental impact statement for annual fisheries management measures, alternatives are different suites of optimum yields and management actions that could be used to manage fisheries.

American Lobster
Scientific name: Homarus americanus; Market name: Lobster; Vernacular name: none

Anadromous
Fishes that migrate as juveniles from freshwater to saltwater and then return as adults to spawn in freshwater; most Pacific salmon are anadromous.

Anchovy (Northern Anchovy)
Scientific name: Engraulis mordax; Market name: Anchovy; Vernacular names: North Pacific Anchovy, California Anchovy, Northern Anchovy

Angler
A person catching fish or shellfish with no intent to sell, including people releasing the catch. (see Recreational Fishery)

Annual (Total) Mortality (Rate)
1. The rate of death, usually in terms of a percentage of fish dying from a population in one year, due to both fishing and natural causes; 2. The ratio of the number of fish which die during a year divided by the number alive at the beginning of that year.

Anoxic
The condition of oxygen deficiency or absence of oxygen. Anoxic sediments and anoxic bottom waters are commonly produced where there is a deficiency of oxygen due to very high organic productivity and a lack of oxygen replenishment to the water or sediment, as in the case of stagnation or stratification of the water body.

Aphotic
Light level modifier of the deep epipelagic ocean ecosystem, and turbid regions of all other waters; areas never reached by natural light.

Aquaculture
The farming of aquatic organisms including fish, mollusks, crustaceans, and aquatic plants with some sort of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated.

Archipelago
A group of islands; an expanse of water with scattered islands.

Area Closure
The closure to fishing by particular gear(s) of an entire fishing ground, or a part of it, for the protection of a section of the population (e.g. spawners, juveniles), the whole population, or several populations. The closure is usually seasonal but it could be permanent.

Arrowtooth Flounder
Scientific name: Atheresthes stomias; Market name: Flounder, Arrowtooth; Vernacular name: Arrowtooth Halibut, Turbot, Paltus

Artisanal Fishery
A fishery based on traditional or small-scale gear and boats.

Assemblage
1. An association of coexisting species, in space and time, with similar environmental tolerance, possibly trophic relationships, but not totally interdependent; 2. A collection of species inhabiting a given area, the interactions between the species, if any, being unspecified.

Assessment
A judgment made by a scientist or scientific body on the state of a resource, such as a fish stock (e.g. size of the stock, potential yield, on whether it is over- or underexploited), usually for the purpose of passing advice to a management authority.

Assessment Level
Categories of the level of complexity of, and data available for each assessment: index of abundance (Index), yield-per-recruit analysis (Yield), analysis of the age structure of the catch (Age Structure), analysis including the relationship between recruitment and spawning stock size (Spawning Stock), and assessment that allows prediction of future (1 or 2 years ahead) stock sizes and catches (predictive).

Associated Species
Those species that (a) prey upon the target species, (b) are preyed on by it, (c) compete with it for food, living space, etc., or (d) co-occur in the same fishing area and are exploited (or accidentally taken) in the same fishery or fisheries. These interactions can occur at any stage of the life cycle of one or other species and the range of species concerned can therefore be very large.

Atlantic Cod
Scientific name: Gadus morhua; Market name: Cod; Vernacular names: Codling, Scrod cod

Atlantic Herring
Scientific name: Clupea harengus; Market names: Herring, Sea Herring, Sild; Vernacular names: Common Herring, Labrador Herring, Sardine, Sperling

Atlantic Pollock
Scientific name: Pollachius virens; Market name: Pollock; Vernacular names: Saithe, Coalfish, Coley, Green Cod, Boston Bluefish

Atlantic Salmon
Scientific name: Salmo salar; Market name: Atlantic Salmon; Vernacular names: Sea Run Salmon, Kelts, Black Salmon

Atlantic Sea Scallop
Scientific name: Placopecten magellanicus; Market name: Scallop; Vernacular name: none

Atlantic Striped Bass Scientific name: Morone saxatilis; Market name: Bass; Vernacular names: Rockfish, Striper, Linesides

Atlantic Surfclam
Scientific name: Spisula solidissima; Market names: Clam, Surfclam; Vernacular names: Hen clam, Bar clam, and Sea clam

Atoll
Earthform consisting of a ringlike perimeter reef area, often with a reef islet, enclosing a lagoon area. (see Lagoon, Reef)

Availability
1. The fraction of a fish population which lives in regions where it is susceptible to fishing during a given fishing season. This fraction receives recruits from or becomes mingled with the non-available part of the stock at other seasons, or in other years (any more or less completely isolated segment of the population is best treated as a separate stock); 2. The proportion of a stock which is susceptible to fishing. Fish become "available" to fisheries through migration, growth and /or change of behavior (from pelagic to demersal). If an available section of a stock is sufficiently isolated from the rest of the stock, it could be considered a management unit and be managed as such; 3. Describes whether a certain kind of fish of a certain size can be caught by a type of gear in an area.

B₀ (B "zero")
Unfished or virgin biomass. Rarely known. Using mathematical models, it is generally calculated as the long-term average biomass value expected in the absence of fishing mortality. In production models, B0 is also known as carrying capacity. It is often used as a biological reference point in fisheries management.

B_MSY
1. Long-term average biomass that would be achieved if fishing at a constant fishing mortality rate equal to F_MSY; 2. The weight (biomass) of a group of fish necessary to produce maximum sustainable yield (MSY).

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

Bank
Submerged earthform with a crest at a depth of 20-200 meters in oceanic waters and of 0-5 meters in nearshore and neritic waters. (see Nearshore, Neritic Zone)

Barrier Island
A sedimentary island, generally elongate and low, that is built by longshore transport or wave action parallel to the coast.

Barrier Reef
A reef growing offshore from a land mass and separated from the shoreline, often by a lagoon or estuary. (see Estuary, Lagoon)

Baseline
A set of reference data sets or analyses used for comparative purposes; it can be based on a reference year or a reference set of (standard) conditions.

Basin
Any large depression in which sediments are deposited.

Bathyl Zone
The seafloor between depths of 1,000 meters and approximately 4,000 meters.

Bathymetry
Pertaining to the depth and relief of water basins.

Bathypelagic Zone
The pelagic environment between depths of 1,000 meters and 4,000 meters.

Bayesian
A formal statistical approach in which expert knowledge or beliefs are analyzed together with data. Bayesian methods make explicit use of probability for quantifying uncertainty. Bayesian methods are particularly useful for making decision analyses. (see Monte Carlo)

Beach
A sloped sediment shoreline composed of sand, gravel, cobble, mud, or boulder-sized sediments, sometimes with beach rock.

Benthic
1. Defining a habitat or organism found on the sea bottom; 2. Of or pertaining to the seafloor (or bottom) of a water body. (see Demersal, Pelagic)

Benthos
Organisms that live on or in the seabottom.

Best Available Science
The term "best available science" comes from National Standard 2 listed in the Magnuson-Stevens Act, and is the informational standard mandated for decision making.

Bias
A systematic difference between the expected value of a statistical estimate, and the quantity it estimates.

Billfish
A group of tuna-like fish species comprising marlins, sailfish, and spearfish, and which are characterized by a snout which extends into a bill or spear.

Bioaccumulation
The buildup over time, within animal tissues, of substance (e.g. heavy metals) that cannot be excreted by an organism.

Bioeconomic Modeling
Mathematical formulae that simulate the interaction between biological behavior of fish stocks and human behavior of users of the resource as it is shaped by economic factors.

Biogeography
The distribution of one or more species that is defined by abiotic factors (temperature, salinity, surface currents, etc.).

Biological Assessment
An assessment conducted as part of the Endangered Species Act (ESA).

Biological Diversity (Biodiversity)
1. The variety and variability among living organisms from all sources, including 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 may reflect ecosystem stresses (such as those due to high fishing intensity); 2. Includes genetic diversity (within species), species diversity (within ecosystems), and ecosystem diversity. (see Species Diversity)

Biological Opinion
A scientific assessment issued by the National Marine Fisheries Service (NMFS) or U.S. Fish and Wildlife Service (USFWS), as required by the Endangered Species Act (ESA) for listed species. Determines the likelihood of an action to jeopardize the existence of a species listed under the ESA.

Biological Reference Points
1. A biological benchmark against which the abundance of the stock or the fishing mortality rate can be measured in order to determine its status. These reference points can be used as limits or targets, depending on their intended usage; 2. Specific values for the variables that describe the state of a fishery system which are used to evaluate its status. Reference points are most often specified in terms of fishing mortality rate and/or spawning stock biomass. These may indicate (a) a desired state of the fishery, such as a fishing mortality rate that will achieve a high level of sustainable yield, or (b) a state of the fishery that should be avoided, such as a high fishing mortality rate which risks a stock collapse and long-term loss of potential yield. The former are referred to as "target reference points", and the latter are referred to as "limit reference points" or "thresholds". Some common examples are F_0.1, F_MAX, and F_MSY.

Biomass (B)
1. Or standing stock. The total weight of a group (or stock) of living organisms (e.g. fish, plankton) or of some defined fraction of it (e.g. spawners) in an area, at a particular time; 2. Measure of the quantity, usually by weight in pounds or metric tons (2,205 pounds or 1 metric ton), of a stock at a given time.

Biota
The plant and animal life characteristic of a specific region or biosphere, or given time period.

Biotic
Pertaining to the living components of their environment.

Blocked Quota Shares
In Alaska, quota shares in the Alaskan halibut and sablefish individual fishing quota (IFQ) program that are not allowed to be subdivided when transferred. There are limits on the size of the blocked quota and on the number of blocks that an individual may own in a given area. This is intended to ensure the availability of small units of quota for purchase by new entrants. (see Unblocked Quota Shares)

Bloom
A sudden increase in the abundance of alga or phytoplankton resulting in a contiguous mass of highly concentrated phytoplankton in the water column.

Bluefin Tuna
Scientific name: Thunnus thynnus; Market name: Tuna, Bluefin Tuna, Toro, Maguro; Vernacular names: Albacore, Giant Bluefin, Northern Bluefin Tuna, Tunny, Oriental Tuna

Bluefish
Scientific name: Pomatomus saltatrix; Market name: Bluefish; Vernacular names: Tailor, Snapper

Bony Fishes
Fishes with a calcified hard skeleton and belonging to Class Osteichthyes; includes most fish species except sharks, rays, skates, hagfish, and lampreys.

Bootstrap
A statistical methodology used to quantify the uncertainty associated with estimates obtained from a model. The bootstrap is often based on Monte Carlo resampling of residuals from the initial model fit. (see Monte Carlo)

Boundary Current
Large-scale water stream in the upper ocean that separates water masses; is driven by a combination of wind, temperature, geostrophic, or coriolis effects.

Brown Shrimp
Scientific name: Farfantepenaeus aztecus; Market name: Shrimp; Vernacular name: none

Buffer Zone
The area that separates the core from areas in which human activities that threaten it occur.

Bycatch
Fish other than the primary target species that are caught incidental to the harvest of the primary species. Bycatch may be retained or discarded. Discards may occur for regulatory or economic reasons.

Bycatch Reduction (Excluder) Device
A device inserted in a fishing gear (usually trawl nets, close to the codend) to allow escapement, alive, of unwanted (nontarget and prohibited) species (e.g. jellyfish), smaller fish (juveniles), and threatened or endangered species (e.g. sea turtles, marine mammals).

CAGEAN
Catch-at-age analysis. An analysis used to reconstruct the population history of long-lived fish stocks. They provide an estimate of the current "exploitable biomass" (the part of the population that can be fished), upon which the harvest rate is based.

Capability
The ability to do something with the capacity you have; the capacity to be used, treated, or developed for a specific purpose.

Capacity
1. The ability to sustain, harvest, hold, or process; 2. The maximum amount that can be produced per unit of time with existing plant and equipment, provided the availability of variable factors of production is not restricted.

Carrying Capacity
1. The maximum population of a species that an area or specific ecosystem can support indefinitely without deterioration of the character and quality of the resource; 2. The level of use, at a given level of management, at which a natural or man-made resource can sustain itself over a long period of time. For example, the maximum level of recreational use, in terms of numbers of people and types of activity, that can be accommodated before the ecological value of the area declines.

Cash Flow Analysis
A type of financial analysis that compares the timing and amount of cash inflows with the timing and amount of cash outflows. A firm's cash flow position can greatly affect its ability to remain in business. These effects may not be apparent from a cost-benefit analysis.

Catadromous
Fishes that spend most of their life in freshwater and then migrate into saltwater to spawn.

Catch
1. To undertake any activity that results in taking fish out of its environment dead or alive. To bring fish on board a vessel dead or alive; 2. The total number (or weight) of fish caught by fishing operations. Catch should include all fish killed by the act of fishing, not just those landed; 3. The component of fish encounter-ing fishing gear, which is retained by the gear.
Comment: The catch is usually expressed in terms of wet weight. It refers sometimes to the total amount caught, and sometimes only to the amount landed. The fish which are not landed, but returned to the sea, are called discards.

Catchability
1. In general, the extent to which a stock is susceptible to fishing. (see Vulnerability)
Comment: Catchability often increases with developments in fishing technology, and so needs to be monitored. It depends on the habits of the fish as well as on the type and deployment of fishing gear. It may also depend on the abundance of the fish (e.g. less abundant fish may be more catchable due to less saturation of gear or to concentration in schools). Specific climatic conditions may result in increased or decreased availability of the fish. This would lead to increased (or decreased) catchability and, thus, increased (or decreased) fishing mortality rate with the same fishing effort.

Catchability Coefficient (q)
1. In fisheries models, the factor (q) relates abundance to stock size (x = qN) and fishing mortality to fishing effort (F = qf). Following the latter, (q) is a measure of fishing mortality generated on a stock by one unit of effort; 2. The fraction of a fish stock which is caught by a defined unit of the fishing effort. When the unit is small enough that it catches only a small part of the stock--0.01 or less-it can be used as an instantaneous rate in computing population change.

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.

Catcher Vessel
Vessel that harvests fish but does not have onboard processing capacity.

Catcher-Processor Vessel
Vessel that can both catch and process the catch onboard. Also referred to as factory trawlers or freezer-longliners.

Catch Per Unit (of) Effort (CPUE)
The quantity of fish caught (in number or in weight) with one standard unit of fishing effort; e.g. number of fish taken per 1,000 hooks per day or weight of fish, in tons, taken per hour of trawling. CPUE is often considered an index of fish biomass (or abundance). Sometimes referred to as catch rate. CPUE may be used as a measure of economic efficiency of fishing as well as an index of fish abundance. Also called: catch per effort, fishing success, availability.

Catch Rate
Means sometimes the amount of catch per unit time and sometimes the catch per unit effort.

Ceremonial and Subsistence
A harvest category specific to Native American tribes representing fishing rights granted by treaty.

Cetaceans
Marine mammals of the Order Cetacea. Includes whales, dolphins, and porpoises.

Charter Boat
Any vessel-for-hire engaged in recreational fishing and hired for a charter fee by an individual or group of individuals (for the exclusive use of that individual or group of individuals), which results in that vessel being unavailable for hire to any other individual or group of individuals during the period of the charter.

Chinook Salmon
Scientific name: Oncorhynchus tshawytscha; Market names: Chinook, King, or Spring Salmon; Vernacular names: Tyee, Winter, Quinnat, King, or Spring Salmon

Closed Season
Seasonal closure. The banning of fishing activity (in an area or of an entire fishery) for a few weeks or months, usually to protect juveniles or spawners.

Coastal Pelagic Species
Schooling fish not associated with the ocean bottom that migrate in coastal waters. They usually eat plankton and are the main food source for higher-level predators such as tuna, salmon, most groundfish, and humans. Examples include herring, squid, sardine, and mackerel.

Coastal Zone Management Act (CZMA)
The main objective of the CZMA is to encourage and assist states in developing coastal zone management programs, to coordinate state activities, and to safeguard the regional and national interests in the coastal zone. It requires that any Federal activity (including fishery management regulations) directly affecting the coastal zone of a state be consistent with that state's approved coastal zone management program, since activities that take place beyond the territorial sea may affect the coastal zone.

Code of Federal Regulations (CFR)
A codification of the regulations published in the Federal Register by the executive departments and agencies of the Federal government. The CFR is divided into 50 titles that represent broad areas subject to Federal regulation. Title 50 contains wildlife and fisheries regulations. (see Proposed Rule)

Coded-wire Tag
Coded-wire tags are small pieces of stainless steel wire that are injected into the snouts of juvenile salmon and steelhead. Each tag is etched with a binary code that identifies its release group.

Codend
The end of a trawl net that retains the catch and the part of the net where most size-selection takes place. Codend mesh sizes and structure are usually regulated and may be preceded by a sorting grid to reduce bycatch. (see Bycatch Reduction Device)

Coefficient of Variation (CV)
The standard error of a statistic, divided by its point estimate. The CV gives an idea of the precision of an estimate, independent of its magnitude.

Cohort
1. In a stock, a group of fish generated during the same spawning season and born during the same time period; 2. In cold and temperate areas, where fish are long-lived, a cohort corresponds usually to fish born during the same year (a year class). For instance, the 1987 cohort would refer to fish that are age 0 in 1987, age 1 in 1988, and so on. In the tropics, where fish tend to be short-lived, cohorts may refer to shorter time intervals (e.g. spring cohort, autumn cohort, monthly cohorts). (see Year Class)

Cohort Analysis
A retrospective analysis of the catches obtained from a given year class at each age (or length interval) over its life in the fishery. Allows estimation of fishing mortality and abundance at each age as well as recruitment. Involves the use of a simplified algorithm based on an approximation that assumes that, in a given time period, all fishing takes place instantaneously in the middle of the time period. (see Virtual Population Analysis)

Cohort Replacement Rate
The rate at which each subsequent cohort or generation replaces the previous one.

Commercial Fishery
A term related to the whole process of catching and marketing fish and shellfish for sale. It refers to and includes fisheries resources, fishermen, and related businesses.

Common Property
Form of resource ownership with a set of well-defined users capable of excluding other potential users and having well-understood rules regarding their rights and obligations with respect to other users and the resource.

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 the air. The government regulates the use of a common property resource to ensure its future benefits.

Common Thresher Shark
Scientific name: Alopias vulpinus; Market name: Thresher Shark; Vernacular name: Fox Shark, Sea Fox, Swingletail, Whiptail Shark, Thintail Shark

Community
The populations that live and interact physically and temporally in the same area.

Community Development Quota (CDQ)
Program in western Alaska under which a percentage of the total allowable catch (TAC) of Bering Sea commercial fisheries is allocated to specific communities. Communities eligible for this program must be located within 50 miles of the Bering Sea coast, or on an island within the Bering Sea; meet criteria established by the State of Alaska; be a village certified by the Secretary of the Interior pursuant to the Alaska Native Claims Settlement Act; and consist of residents who conduct more than half of their current commercial or subsistence fishing in the Bering Sea or waters surrounding the Aleutian Islands. Currently 7.5% of the TAC in the pollock, halibut, sablefish, crab, and groundfish fisheries is allocated to the CDQ program.

Compensatory Growth
An increase in growth rate shown by fishes when their populations fall below a certain level; possibly caused by decreased competition between individuals for food or space.

Compensatory Survival
A decrease in the rate of natural deaths that some fishes may show when their populations fall below a certain level; possibly caused by decreased competition between individuals for food or space. (see Natural Mortality)

Conceptual Model
A depiction or representation of the most current understanding of the major ecosystem features and processes (including biological, physical, chemical, and geopmorphic components) of a particular environment (e.g. estuaries).

Condition Factor (K)
A mathematical measurement of the degree of "plumpness", or the general health of a fish or group of fishes.

Confidence Interval (CI)
The probability, based on statistics, that a number will be between an upper and lower limit.

Connectivity
The movement of organisms from place to place (e.g. among marine reserves) through dispersal or migration. (see Marine Reserves)

Consumer Surplus
The welfare (or well-being) consumers derive from a good or service, represented by the difference between the maximum a consumer is willing to pay for a good or service and what the consumer actually pays. "Consumer" also applies to those gaining value from non-consumptive uses (e.g. observing salmon runs) and to nonuse benefits (e.g. protecting marine mammals from exploitation). (see Producer Surplus, Total Welfare)

Contiguous Fishery Zone (CFZ)
The 9-nautical-mile (n.mi.) seaward zone, from 3 to 12 n.mi. offshore, and adjacent to the 3-n.mi. territorial sea.

Continental Margin
The edge of a continent; the zone between a continent and the deep-sea floor of the abyssal plain.

Continental Rise
Part of the continental margin; the ocean floor from the continental slope to the abyssal plain. The continental rise generally has a gentle slope and smooth topography.

Continental Shelf
Underwater portion (shelf) of the continent, with moderate inclination, extending seaward from the shore to the edge of the continental slope where the inclination increases rapidly. Sometimes conventionally considered as the continent margin between 0 and 200 meters depths. (see Shelf Break)

Continental Slope
Part of the continental margin; the ocean floor from the continental shelf to the continental rise or oceanic trench. Usually to a depth of about 200 meters. The continental slope typically has a relatively steep grade from 3 to 6 degrees.

Contingent Valuation
A method employing a hypothetical market to elicit people's preferences for a non-market good; typically people are questioned about what they are willing to pay or receive for specific increments or decrements in the provision of the good.

Control Date
Date established for defining the pool of potential participants in a given management program. Control dates can establish a range of years during which a potential participant must have been active in a fishery in order to qualify for quota share.

Control Rule
Describes a plan for pre-agreed management actions as a function of variables related to the status of stock in question. For example, a control rule can specific how fishing mortality or yield should vary with levels of estimated biomass.

Controlled Access
General term for management schemes that reduce or restrict the number of participants in a fishery. (see Limited Entry)

Convention on the International Trade of Endangered Species (CITES)
A voluntary international agreement between governments aimed at ensuring the international trade of specimens of wild animals and plants does not threaten their survival.

Convergence Zone
The line where two oceanic water masses meet, resulting in the sinking of the denser one.

Co-Occurring Stocks
Different stocks of fish that swim or school near one another, and may be caught together.

Coral Reef
The massive deposition of calcium carbonate by coral polyps of colonial stony corals and other organisms producing large living hard structures. Coral reefs can range in size from a few feet to thousands of miles.

Core Area
The central, most highly protected part of a protected area. (see Marine Reserve, Protected Area)

Cost-Benefit Analysis
1. A comparison of the economic benefits and costs of a project, policy, or regulation; 2. A comparison of the economic benefits of using a resource to the opportunity cost if the resource is used. Projects or regulations are typically evaluated based on how they change the cost-benefit ratio.

Council
A regional fisheries management council (FMC). The Fishery Conservation and Management Act of 1976 as amended created eight regional councils to prepare fishery management plans (FMPs) and FMP amendments for fisheries in the U.S. Exclusive Economic Zone (EEZ).

Critical Areas
Areas within a Marine Protected Area (MPA) that are crucial to achieving the objectives of the MPA; for example, spawning areas in an MPA established for fisheries purposes. (see Marine Protected Area)

Critical Size
The average size of a fish in a year class at the time when the instantaneous rate of natural mortality equals the instantaneous rate of growth in weight for the year-class as a whole. At this size, the biomass of the age class is maximized. (see Optimum Size)

Crustaceans
A group of freshwater and saltwater invertebrates with jointed legs and a hard shell of chitin. Includes shrimps, crabs, lobsters, and crayfish.

Cultural Landscape
A cluster of beliefs, values, and norms about how places and things on earth are related to human behavor.

Culturally Affiliated
To be connected to a place, region, or resource because it has significant meaning to the culture of the individual and his or her group. In most cases cultural affiliation requires more than one generation to establish, and for some groups the connections have been developed over centuries. The Federal government uses the term in various environmental laws and requlations.

Cumulative (Catch) Limit
The total allowable amount of a species or species group, by weight, that a vessel may take and retain, possess, or land during a period of time. Fishers may take as many landings of a species or species complex as they like as long as they do not exceed the cumulative limit that applies to the vessel or permit during the designated period.

Cumulative (Catch) Limit Stacking
The association of cumulative limits with permits, rather than with vessels, allowing a vessel with multiple limited entry permits to harvest multiple cumulative limits. Also known as permit stacking.

Current
A horizontal movement of water.

Current System
Areas strongly influenced by large, unidirectional, organized, coherent flows of water in horizontal motion. These include freshwater inflows and tidal flows. Geostrophic flows are currents in the deep ocean that flow along lines of constant pressure or baroclinic surfaces. Wind-driven currents along the shore, called longshore currents, flow parallel to the land and play a role in sediment transport and structuring of the habitat. Current systems play an especially important role by governing productivity, providing transport for early-life stages (e.g. eggs and larvae) and adults, and flushing pollutants out to sea.(see Primary Productivity, Pollution)

Decision Analysis
A formal analysis to aid decision-making in the face of uncertainty. A decision analysis usually evaluates the expected outcomes (e.g. average catch, constancy of catch, probability of rebuilding to a given biomass target, etc.) of alternative management controls. A decision analysis can also address management consequences under different plausible assumptions about the status of the stock.

Decision Rule
Specification of how pre-agreed management actions will respond to perceived or estimated states of nature.

Decline
A decline is a reduction in the number of individuals, or a decrease of the area of distribution, the causes of which are either not known or not adequately controlled. It need not necessarily still be continuing. Natural fluctuations will not normally count as part of a decline, but an observed decline should not be considered part of a natural fluctuation unless there is evidence for this. A decline that is the result of harvesting that reduces the population to a planned level, not detrimental to the survival of the species, is not covered by the term.

Dedicated Access Privileges (DAP)
Assigns an individual or other entity access to a predetermined portion of the annual catch in a particular fishery. In some cases, the privilege is transferable and may be bought and sold, creating a market. The term encompasses a range of tools, including access privileges assigned to individuals (i.e. individual transferable quotas [ITQs]), and to groups or communities (e.g., community development quotas [CDQs], cooperatives, and area-based quotas).

Deep Shelf and Terrace
Horizontal habitat located from about 40 to 500 meters. Insular habitats on or above the deep shelf consisting of horizontal or nearly horizontal natural typographic features interrupting a steeper slope and often occurring in a series. These habitats extend seaward from the shelf of an island or bank.

Deep Slope
Vertical habitat located from about 40 to 500 meters. Insular habitats on or above the deep slope characterized by a steep (often vertical) slope extending seaward from the shelf of an island or bank These habitats may be colonized by some low-light coral and bryozoans.

Delta
A low, nearly flat accumulation of sediment deposited at the mouth of a river or stream, commonly triangular or fan-shaped.

Delta Method
Also known as the Taylor Series method, the Delta method is a statistical procedure used to quantify the uncertainty associated with estimates obtained from a model. More specifically, the Delta method quantifies how the variance propagates from the parameters that are estimated directly by the statistical model (e.g. current spawning stock biomass, SSB), and those parameters that are derived from the application of mathematical formulations (e.g. future SSB based on model projections).

Demand Function
A function that relates the quantity of a good or service demanded to price. It is usually an inverse relationship where at higher (or lower) prices, less (or more) quantity is consumed. Other factors which influence willingness-to-pay are incomes, tastes, preferences, and price of substitutes.

Demersal
Living in close relation with the bottom and depending on it. Cods, groupers, crabs, and lobsters are demersal resources. The term usually refers to the living mode of the adult, i.e. demersal fish. (see Benthic, Pelagic)

Demography
A term referring to the study of birth rates, death rates, age distributions, and size of populations. It is a fundamental discipline within the larger field of population biology and ecology. (see Population Biology)

Density-Dependence
The dependence of a factor influencing population dynamics (such as survival rate or reproductive success) on population density. The effect is usually in the direction that contributes to the regulative capacity of a stock.

Density-Independent
External factors that influence all individuals of a population, regardless of population density, such as weather or climate.

Depleted Stock
A stock driven by fishing to very low level of abundance compared to historical levels, with dramatically reduced spawning biomass and reproductive capacity. It requires particularly energetic rebuilding strategies and its recovery time will depend on the present condition, the level of protection, and the environmental conditions.

Derby Fishery
A fishery of brief duration during which fishers race to take as much catch as they can before the fishery closes.

Deterministic
1. A deterministic process or model does not take account or include any stochastic (random) variability. The opposite is a stochastic model; 2. A model whose behavior is fully specified by its form and parameters, unlike a stochastic model. (see Simulation, Stochastic)

Detritus
Dead organic matter and the decomposers that live on it; when broken up by decomposers, detritus provides energy to many coastal ecosystems.

Directed Fishery
Fishing that is directed at a certain species or group of species. This applies to both sport and commercial fishing.

Disappearance (Z)
A measure of the rate of decline in the numbers of fish caught as individuals become less numerous or available; often calculated from a catch curve.

Discard
To release or return fish to the sea, dead or alive, whether or not such fish are brought fully on board a fishing vessel.
Comment: Estimates of discards can be made in a variety of ways, including samples from observers and logbook records. Fish (or parts of fish) can be discarded for a variety of reasons such as having physical damage, being a nontarget species for the trip, and compliance with management regulations like minimum size limits or quotas. (see Highgrading)

Distinct Population Segment (DPS)
A DPS, or a distinct population segment, is a vertebrate population or group of populations that is discrete from other populations of the species and significant in relation to the entire species. The ESA provides for listing species, subspecies, or distinct population segments of vertebrate species.

Dolphinfish
Scientific name: Coryphaena hippurus; Market name: Mahi-mahi; Vernacular names: Dorado, Common dolphinfish

Domestic Annual Harvest (DAH)
The domestic annual fishing capacity, modified by other factors (such as economic factors), which will determine estimates of what the fleets will harvest.

Domestic Annual Processing (DAP)
The amount that will be domestically processed, based not only on physical capacity but on a demonstrated intent and the effects of domestic harvesting, markets, and other fisheries.

Dover Sole
Scientific name: Microstomus pacificus; Market name: Sole; Vernacular names: Slime sole, Slippery sole

Downwelling
Hydroform created by convergence of surface currents that causes surface waters to sink, creating vertical and horizontal displacement of water and possibly carrying organisms to lower depths.

Ebb Tide
A falling tide, the phase of the tide between high water and the succeeding low water.

Ecological Reserve
Zoning that protects all living marine resources through prohibitions on fishing and on the removal or disturbance of any living or nonliving resource. (see Protected Area)

Economic Efficiency
1. A measure of the size of consumer surplus and producer surplus. An increase in the combined surpluses is an increase in economic efficiency; 2. 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 (MEY).

Economic Overfishing
A level of fish harvesting that is higher than that of economic efficiency; harvesting more fish than necessary to have maximum profits for the fishery.

Economic Rent
The total amount of profit that could be earned from a fishery owned by an individual after subtracting input costs (usually capital and labor). Individual ownership maximizes economic rent, but an open-entry policy usually results in so many fishermen that profits higher than the opportunity cost are driven to zero.

Economic Value
The most people are willing to pay to use a given quantity of a good or service; or, the smallest amount people are willing to accept to forego the use of a given quantity of a good or service.

Ecosystem
A geographically specified system of organisms, the environment, and the processes that control its dynamics. Humans are an integral part of an ecosystem.

Ecosystem Approach to Fisheries (EAF)
An approach to fisheries management that strives to balance diverse societal objectives by taking into account the knowledge and uncertainties about biotic, abiotic, and human components of ecosystems and their interactions and applying an integrated approach to fisheries within ecologically meaningful boundaries. The purpose of EAF is to plan, develop, and manage fisheries in a manner that addresses the multiple needs and desires of society, without jeopardizing the options for future generations to benefit from the full range of goods and services provided by marine ecosystems.

Ecosystem Approach to Management (EAM)
Management that is adaptive, is specified geographically, takes into account ecosystem knowledge and uncertainties, considers multiple external influences, and strives to balance diverse social objectives.

Ecosystem Assessment
A social process through which the findings of science concerning the causes of ecosystem change, their consequences for human well-being, and management and policy options are brought to bear on the needs of decision makers.

Ecosystem Function
An intrinsic ecosystem characteristic related to the set of conditions and processes whereby an ecosystem maintains its integrity. Ecosystem functions include such processes as decomposition, production, nutrient cycling, and fluxes of nutrients and energy.

Ecosystem Health
A measure of the stability and sustainability of ecosystem functioning or ecosystem services that depends on an ecosystem being active and maintaining its organization, autonomy, and resilience over time. Ecosystem health contributes to human well-being through sustainable ecosystem services and conditions for human health.

Ecosystem-Based Management
An approach that takes major ecosystem components and services-both structural and functional-into account in managing fisheries. It values habitat, embraces a multispecies perspective, and is committed to understanding ecosystem processes. Its goal is to rebuild and sustain populations, species, biological communities, and marine ecosystems at high levels of productivity and biological diversity so as not to jeopardize a wide range of goods and services from marine ecosystems while providing food, revenue, and recreation for humans.

Ecosystem Properties
The size, biodiversity, stability, degree of organization, and internal exchanges of materials and energy among different pools, and other properties that characterize an ecosystem.

Ecosystem Services
Ecosystem services are the benefits people obtain from ecosystems. These include provisioning services, such as food and water; regulating services, such as flood and disease control; cultural services, such as spiritual and cultural benefits; and supporting services, such as nutrient cycling, that maintain the conditions for life on Earth.

Ecotourism
Tourism involving travel to areas of natural or ecological interest for non-consumptive purposes such as observing wildlife or learning about the environment.

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

Egg Survey
A systematic and scientific estimation of the abundance of eggs (and larvae) in an area, through sampling at the bottom or in the water column with appropriate devices (e.g. small meshed midwater trawls, plankton nets). Used to estimate the size of the spawning stock and the importance of spawning.

Elasmobranch
Describes a group of fish without a hard bony skeleton, including sharks, skates, and rays.

El Niño-Southern Oscillation (ENSO)
Abnormally warm ocean climate conditions, which in some years affect the west coast of Latin America (centered on Peru) often around Christmas time. The anomaly is accompanied by dramatic changes in coastal upwelling, species abundance and distribution, higher local rainfall and flooding, and massive deaths of fish and their predators (including birds). Many other climatic anomalies around the world (e.g. droughts, floods, forest fires,) are attributed to consequences of El Niño. (see La Niña, Pacific Decadal Oscillation)

Emergency Action (EA)
A fishery management council (FMC) may decide to propose an EA when a problem arises in a fishery that requires regulations sooner than a fishery management plan amendment can be proposed and implemented. Once implemented, an EA lasts for 90 days but can be extended by the Secretary of Commerce at the council's request.

Endangered Species
A species as defined in the Endangered Species Act, that is in danger of extinction through a significant portion of its range. A species classified as threatened is likely to become an endangered species.

Endangered Species Act (ESA)
The ESA is a statute which was enacted in 1973 to conserve species and ecosystems. Under its auspices, species facing possible extinction are listed as threatened or endangered, or as candidate species for such listings. When such a listing is made, recovery and conservation plans are drawn up to ensure the protection of the species and its habitat.

Endemism
Of or relating to a native species or population occurring under highly restricted conditions due to the presence of a unique environmental factor that limits its distribution.

Endorsement
A designation on a limited entry permit that authorizes the use of the permit for a particular gear, length of vessel, or in a particular segment of the fishery.

English Sole
Scientific name: Pleuronectes vetulus); Market name: Sole; Vernacular name: Lemon sole

Environmental Assessment (EA)
As part of the National Environmental Policy Act (NEPA) process, an EA is a concise public document that provides evidence and analysis for determining whether to prepare an environmental impact statement (EIS) or a finding of no significant impact (FONSI).

Environmental Ethics
A cluster of beliefs, values, and norms regarding how humans should interact with the environment.

Environmental Impact Statement (EIS)
As part of the National Environmental Policy Act (NEPA) process, an EIS is an analysis of the expected impacts resulting from a proposed Federal action (such as fisheries management or a development plan) on the environment. An EIS is required for all fishery management plans as well as significant amendments to existing plans. The purpose of an EIS is to ensure that the proposed Federal action gives appropriate consideration to environmental values in order to prevent harm to the environment.

Environmental Protection Agency (EPA)
A Federal agency charged with enforcing numerous environmental laws (including the Clean Water Act, the Clean Air Act, and the State Drinking Water Act) and supporting state and local governments in establishing and enforcing environmental laws. In addition to enforcement, the EPA researches causes, effects, and remediation of environmental problems. All final environmental impact statements (EIS) are available from the EPA.

Epifauna
Benthic fauna living on the substrate but not burrowing into it (as on a hard seafloor) or living on other organisms. (see Benthic)

Equilibrium Catch
The catch (in numbers) taken from a fish stock when it is in equilibrium with fishing of a given intensity, and (apart from the effects of environmental variation) its abundance is not changing from one year to the next.

Equilibrium Yield (EY)
The yield in weight taken from a fish stock when it is in equilibrium with fishing of a given intensity, and (apart from effects of environmental variation) its biomass is not changing from one year to the next. Also called: sustainable yield, equivalent sustainable yield.

ESA
(See Endangered Species Act)

Escapement
The number or proportion of fish surviving (escaping from) a given fishery at the end of the fishing season and reaching the spawning grounds. The term is generally used for salmon management.

Essential Fish Habitat (EFH)
Congress defined EFH as "those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity" (16 U.S.C. 1802(10)). The EFH guidelines under 50 CFR 600.10 further interpret the EFH definition as follows: Waters include aquatic areas and their associated physical, chemical, and biological properties that are used by fish and may include aquatic areas historically used by fish where appropriate; substrate includes sediment, hard bottom, structures underlying the waters, and associated biological communities; necessary means the habitat required to support a sustainable fishery and the managed species' contribution to a healthy ecosystem; and "spawning, breeding, feeding, or growth to maturity" covers a species' full life cycle.

EFH Assessment
An EFH assessment is a written assessment of the effects of a proposed Federal action on EFH. Federal agencies must provide the National Marine Fisheries Service (NMFS) with an EFH assessment for any action that may adversely affect EFH, except for those activities covered by a general concurrence. An EFH assessment must contain 1) a description of the proposed action; 2) an analysis of the effects, including cumulative effects, of the proposed action on EFH and managed species; 3) the Federal agency's conclusions regarding the effects of the action on EFH; and 4) proposed mitigation, if applicable. If appropriate, the EFH assessment should also include the items listed at 50 CFR 600.920(e)(4). The level of detail in an EFH assessment should be commensurate with the potential impacts to EFH.

EFH Consultation
An EFH consultation refers to the process of satisfying the Federal agency consultation and response requirements of section 305(b)(2) and 305(b)(4)(B) of the Magnuson-Stevens Act, and the EFH conservation recommendation requirement of section 305(b)(4)(A) of that Act. When completed, an EFH consultation generally consists of: 1) notification to the National Marine Fisheries Service (NMFS) of a Federal action that may adversely affect EFH; 2) an EFH assessment provided to NMFS; 3) EFH conservation recommendations provided by NMFS to the Federal action agency; and 4) the Federal agency's response to NMFS EFH conservation recommendations.

EFH Conservation Recommendation
EFH conservation recommendations are recommendations provided by the National Marine Fisheries Service (NMFS) to a Federal or state agency pursuant to section 305(b)(4)(A) of the Magnuson-Stevens Act regarding measures that can be taken by that agency to conserve EFH. EFH conservation recommendations may be provided as part of an EFH consultation with a Federal agency, or may be provided by NMFS to any Federal or state agency whose actions would adversely affect EFH (50 CFR 600.925).

Estimated Discard Mortality
Estimates of discards can be made in a variety of ways, including samples from observers and logbook records.

Estuarine
1. Relating to, or formed in an estuary (e.g. estuarine currents; estuarine animals); 2. Belonging to an estuary (river mouth), an area in which sea water is appreciably diluted by fresh water from rivers.

Estuary
A coastal ecological ecosystem that is partially enclosed, receives freshwater input from land, and has a horizontal fresh-salt salinity gradient; the average salinity of estuarine waters is defined as being 30 practical salinity units (PSU) for at least 1 month per year.

Euryhaline
Organisms able to tolerate a wide range of salinity.

Eutrophication
Generally, the natural or man-induced process by which a body of water becomes enriched in dissolved mineral nutrients (particularly phosphorus and nitrogen) that stimulate the growth of aquatic plants and enhances organic production of the water body. Excessive enrichment may result in the depletion of dissolved oxygen and eventually to species mortality.

Evolutionary Significant Unit (ESU)
An ESU is a distinctive group of Pacific salmon, steelhead, or sea-run cutthroat trout that is uniquely adapted to a particular area or environment and cannot be replaced.

Excess Capacity
In the short-term, fishing capacity that exceeds the capacity required to capture and handle the allowable catch. In the long-term, fishing capacity that exceeds the level required to ensuring the sustainability of the stock and the fishery at the desired level. Fishing capacity in excess of what is required to reach the agreed catch or effort objectives materialized by agreed target reference points (e.g. MSY, F0.1, MEY, etc.).

Exclusive Economic Zone (EEZ)
The EEZ is the area that extends from the seaward boundaries of the coastal states (3 nautical miles (n.mi.) in most cases, the exceptions are Texas, Puerto Rico and the Gulf coast of Florida at 9 n.mi.) to 200 n.mi. off the U.S. coast. Within this area the United States claims and exercises sovereign rights and exclusive fishery management authority over all fish and all continental shelf fishery resources.

Executive Order 12866
A presidential Executive Order that, among other things, requires Federal agencies to assess the economic costs and benefits of all regulatory proposals and complete a regulatory impact analysis (RIA) that describes the costs and benefits of the proposed rule and alternative approaches, and justifies the chosen approach. (see Regulatory Flexibility Act)

Exempted Fishing Permit
A permit issued by NMFS that allows exemptions from some fishery regulations for testing, public display, data collection, exploratory fishing, health and safety, environmental cleanup, and/or hazard removal purposes. Previously known as an "experimental fishing permit."

Existence Value
The economic value of knowing that a resource exists, irrespective of the ability to use the resource now or in the future. (see Heritage Value)

Exploitable Biomass
Refers to that portion of a stock's biomass that is available to the fishing gear.

Exploitation Pattern
The distribution of fishing mortality over the age composition of the fish population, determined by the type of fishing gear, area and seasonal distribution of fishing, and the growth and migration of the fish. The pattern can be changed by modifications to fishing gear; for example, increasing mesh or hook size, or by changing the ratio of harvest by gears exploiting the fish (e.g. gillnet, trawl, hook and line, etc.).

Exploitation Rate
The proportion of a population at the beginning of a given time period that is caught during that time period (usually expressed on a yearly basis). For example, if 720,000 fish were caught during the year from a population of 1 million fish alive at the beginning of the year, the annual exploitation rate would be 0.72.

Ex-Vessel
Refers to activities that occur when a commercial fishing boat lands or unloads a catch. For example, the price received by a captain (at the point of landing) for the catch is an ex-vessel price.

F-Ratio
The ratio of fishing mortality on the oldest age group to the fishing mortality of the preceding age group. Annual F-ratios are estimable parameters in many virtual population analysis (VPA) assessments.

Factory Trawler
A large stern trawler equipped with plant for gutting, filleting, freezing and storing fish, and for processing fish oil and fishmeal. Such vessels usually have extensive superstructures.

Fathom
1.83 meters, equivalent to 6 feet.

Fecundity
The potential reproductive capacity of an organism or population expressed in the number of eggs (or offspring) produced during each reproductive cycle. Fecundity usually increases with age and size. The information is used to compute spawning potential.

Federal Register (FR)
The Federal Register is the official daily publication for rules, proposed rules, and notices of Federal agencies and organizations, as well as executive orders and other presidential documents. Fisheries regulations are not considered final until they are published in the Federal Register. (see Rulemaking)

Fillet
A slice of meat without bones, cut out for human consumption.

Financial Analysis
Cost accounting based on market prices as opposed to opportunity costs.

Financial Ratio
A method of evaluating a firm's financial position. An example is the "current ratio" which is equal to current assets divided by current liabilities.

Finding of No Significant Impact (FONSI)
As part of the National Environment Policy Act (NEPA) process, a FONSI is a document that explains why an action that is not otherwise excluded from the NEPA process, and for which an environmental impact statement (EIS) will not be prepared, will not have a significant effect on the human environment.

Finfish
Vertebrate and cartilanginous fishery species, not including crustaceans, cephalopds, or other mollusks.

Finning
The practice of removing fins and discarding the carcass, usually pertaining to sharks.

Fish
Used as a collective term, includes mollusks, crustaceans and any aquatic animal which is harvested.

Fish Aggregating Device (FAD)
Artificial or natural floating objects placed on the ocean surface, often anchored to the bottom, to attract several schooling fish species underneath, thus increasing their catchability.

Fish Meal
Protein-rich meal derived from processing whole fish (usually small pelagic fish, and fishery bycatch) as well as residues and byproducts from fish processing plants (fish offal). Used mainly as agriculture feeds for poultry, pigs, and aquaculture feeds for carnivorous aquatic species.

Fish Stock
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 from other stocks of the same species and hence self-sustaining. In a particular fishery, the fish stock may be one or several species of fish but here is also intended to include commercial invertebrates and plants.

Fisher
A gender-neutral name for a person (male or female) participating in a fishery.

Fisheries Management
The integrated process of information gathering, analysis, planning, decision making, allocation of resources, and formulation and enforcement of fishery regulations by which the fisheries management authority controls the present and future behaviors of the interested parties in the fishery in order to ensure the continued productivity of the living resources.

Fisheries Management Authority
The body which makes the decisions on how the fishery is carried out, and is responsible for all ancillary services, such as statistics gathering, assessment, monitoring, control and surveillance, consultation with fishers and other users of the sea, and resource allocation or determining the conditions of access to the fishery.

Fisheries Management Organization
Institution 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 the collection of information, its analysis, stock assessment, monitoring, control and surveillance, consultation with interested parties, application and/or determination of the rules of access to the fishery, and resource allocation. Also called: fishery management arrangement.

Fishery
1. Generally, a fishery is an activity leading to harvesting of fish. It may involve capture of wild fish or raising of fish through aquaculture; 2. A unit determined by an authority or other entity that is engaged in raising or harvesting fish. Typically, the unit is defined in terms of some or all of the following: people involved, species or type of fish, area of water or seabed, method of fishing, class of boats, and purpose of the activities.; 3. The combination of fish and fishers in a region, the latter fishing for similar or the same species with similar or the same gear types.

Fishery Conservation and Management Act (FCMA)
The Fishery Conservation and Management Act of 1976 is the Federal law that created the regional fishery management councils and is the Federal government's basis for fisheries management in the U.S. Exclusive Economic Zone (EEZ). It has been reauthorized a number of times and was renamed the Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens Act) in honor of the late Washington Senator, Warren G. Magnuson, in 1980, and in 1996, added Alaska Senator Ted Stevens.

Fishery Conservation Zone (FCZ)
The FCZ is the area from the seaward limit of state waters out to 200 nautical miles. Since 1981, it is referred to as the U.S. Exclusive Economic Zone (EEZ).

Fishery-Dependent
Data collected directly on a fish or fishery from commercial or sport fishermen and seafood dealers. Common methods include logbooks, trip tickets, port sampling, fishery observers, and phone surveys. (see Fishery-Independent)

Fishery Economic Assessment Model (FEAM)
FEAM uses historical landings data, information on industry cost and margin structure (vessels and processors), and income multipliers generated by IMpact analysis for PLANing (IMPLAN), a regional economic impact model, to produce estimates of "regionalized" local income impact after deducting for leakage of payments to nonresidents and to non-local suppliers, wholesalers, and manufacturers.

Fishery-Independent
Characteristic of information (e.g. stock abundance index) or an activity (e.g. research vessel survey) obtained or undertaken independently of the activity of the fishing sector. Intended to avoid the biases inherent to fishery-related data. (see Fishery-Dependent)

Fishery Management Council (FMC)
A regional fisheries management body established by the Magnuson-Stevens Act to manage fishery resources in eight designated regions of the United States.
Comment: "Council membership is a balance of commercial and recreational fisherman, marine scientists and state and Federal fisheries managers, who combine their knowledge to prepare fishery management plans (FMPs) for stocks of finfish, shellfish and crustaceans. In developing these FMPs the councils use the most recent scientific assessments of the ecosystems involved with special consideration of the requirements of marine mammals, sea turtles and other protected resources." [Magnuson-Stevens Act]

Fishery Management Plan (FMP)
1. A document prepared under supervision of the appropriate fishery management council (FMC) for management of stocks of fish judged to be in need of management. The plan must generally be formally approved. An FMP includes data, analyses, and management measures. 2. A plan containing conservation and management measures for fishery resources, and other provisions required by the Magnuson-Stevens Act, developed by fishery management councils or the Secretary of Commerce.

Fishery Management Unit (FMU)
A fishery or a portion of a fishery identified in a fishery management plan (FMP) relevant to the FMP's management objectives. The choice of stocks or species in an FMU depends upon the focus of FMP objectives, and may be organized around biological, geographic, economic, technical, social, or ecological perspectives.

Fishery Models
Simplified representations of the fisheries complex reality. May or may not be a mathematical representation. (see Simulation)

Fishery Policy
Measures by which a national government, regional or state authority, attempts to influence or control the behavior of individuals, companies, and communities in the fisheries sector to achieve certain objectives. The measures can be of varied kinds including fiscal measures, (e.g. taxes, subsidies, public investments, etc.); trade measures (e.g. import and export duties; quotas); social measures (health and education services); regulations (i.e. on food quality; means and types of fish harvesting; individual transferable quotas); and others.

Fishery Reserve
Zoning that precludes fishing activity on some or all species to protect critical habitat, rebuild stocks (long term, but not necessarily permanent closure), provide insurance against overfishing, or enhance fishery yield.

Fishery Resource
In general, refers to elements of a natural aquatic resource (e.g. strains, species, populations, stocks, assemblages that can be legally caught by fishing). May sometimes be taken as including also the habitat of such resources.

Fishery Technology
The equipment and practices for finding, harvesting, handling, processing, and distributing aquatic resources and their products.

Fishing
Any activity, other than scientific research conducted by a scientific research vessel, that involves the catching, taking, or harvesting of fish; or any attempt to do so; or any activity that can reasonably be expected to result in the catching, taking, or harvesting of fish and any operations at sea in support of it.

Fishing Capacity
1. The ability of a stock of inputs (capital) to produce output (measured as either effort or catch); 2. The maximum amount of fish over a period of time (year, season) that can be produced by a vessel or fleet of vessels if fully utilized, given the biomass and age structure of the fish stock and the present state of the technology. The "fishing fleet" is the stock of inputs (i.e. physical capital and human capital). The term "fully utilized" is used in a precautionary context in that it assumes that capacity utilization is 100 percent; 3. The quantity of fish that can be taken by a fishing unit, for example an individual, community, vessel, or fleet, assuming that there is no limitation on the yield from the stock, usually expressed in terms of some measure of vessel size, such as gross tonnage, hold capacity, horsepower. Reflects potential rather than nominal fishing effort.

Fishing Community
A community that is substantially dependent on or substantially engaged in the harvest or processing of fishery resources to meet social and economic needs. Includes fishing vessel owners, fishing families, operators, crew, recreational fishers, fish processors, gear supplies, and others in the community who depend on fishing.

Fishing Effort
The amount of fishing gear of a specific type used on the fishing grounds over a given unit of time (e.g. hours trawled per day, number of hooks set per day, or number of hauls of a beach seine per day). When two or more kinds of gear are used, the respective efforts must be adjusted to some standard type before being added. Sometimes referred to as effective fishing effort.
Comment: The effort may be nominal, reflecting the simple total of effort units exerted on a stock in a given time period. It may also be standard or effective when corrected to take account of differences in fishing power and efficiency and ensure direct proportionality with fishing mortality. Relates usually to a specific fishery and gear. If more than one gear is considered, standardization in relation to one of them is necessary. For biologists, a good measure of fishing effort should be proportional to fishing mortality. For economists it should be proportional to the cost of fishing.

Fishing Gear
The equipment used for fishing (e.g. gillnet, hand line, harpoon, haul seine, long line, bottom and midwater trawls, purse seine, rod-and-reel, pots and traps). Each of these gears can have multiple configurations.

Fishing Intensity
1. In general, and mainly for trawling, the fishing effort exerted per unit of areas (e.g. in hours of trawling per 100 square miles). In stock assessment theory, the effective (or standard) fishing effort per unit area must be proportional to fishing mortality through the relation F = q(f/A) where (f/A) is the fishing intensity, and q is the catchability coefficient; 2. Effective fishing effort; 3. Fishing effort per unit area; 4. Effectiveness of fishing.

Fishing Mortality (F)
1. F stands for the fishing mortality rate in a particular stock. It is roughly the proportion of the fishable stock that is caught in a year; 2. A measurement of the rate of removal from a population by fishing. Fishing 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.

F_0.1
The fishing mortality rate which the increase in yield per recruit in weight for an increase in a unit of effort is only 10 percent of the yield per recruit produced by the first unit of effort on the unexploited stock (i.e. the slope of the yield-per-recruit curve for the F_0.1 rate is only one-tenth the slope of the curve at its origin).

F_10%
The fishing mortality rate that reduces the spawning stock biomass per recruit (SSB/R) to 10 % of the amount present in the absence of fishing.

F_HIGH
Fishing mortality rate corresponding to an equilibrium spawning potential ratio equal to the inverse of the 90th percentile observed survival ratio.

F_LOW
Fishing mortality rate corresponding to an equilibrium spawning potential ratio equal to the inverse of the 10th percentile observed survival ratio.

F_MED
Fishing mortality rate corresponding to an equilibrium Spawning Potential Ratio equal to the inverse of the median observed survival ratio.

f_MSY
Effective fishing effort corresponding to F_MSY.

F_MSY
The fishing mortality rate that, if applied constantly, would result in maximum sustainable yield (MSY). Used as a biological reference point, F_MSY is the implicit fishing mortality target of many regional and national fishery management authorities and organizations. F_MSY can be estimated in two ways: a) from simple biomass-aggregated production models; b) from age-structured models that include a stock-recruitment relationship.

1. The level of fishing mortality (rate of removal by fishing) that produces the greatest yield from the fishery; 2. A biological reference point. It is the fishing mortality rate that maximizes equilibrium yield per recruit. F_MAX is the F level often used to define growth overfishing. In general, F_MAX is different (and higher) than F_MSY depending on the stock-recruitment relationship. By definition, F_MAX is always higher than F_0.1.

F_T (also F_EXTINCTION, F_CRASH)
Fishing mortality rate corresponding to an equilibrium spawning potential ratio equal to the inverse of the survival ratio at the origin of the stock-recruitment relationship. A stock fished at or above this level for a prolonged period of time is expected to collapse.

F_{X %}
Fishing mortality rate that results in x % equilibrium spawning potential ratio.

Fishing Power
1. The catch which a particular gear or vessel takes from a given density of fish during a certain time interval. For example, larger vessels (horsepower) have a greater ability to catch more fish, thus the greater their fishing power. Also, improvements in a vessel or gear, such as fish finders, global positioning systems, etc., can increase fishing power; 2. Of a boat, or of a fishing gear: The relative vulnerability of the stock to different boats or gears. Usually determined as the catch taken by the given apparatus, divided by the catch of a standard apparatus fishing at nearly the same time and place. (see Standardization)
Comment: In such a definition, fishing power is not measured in absolute terms and is dependent on stock size. For this reason, in practice, fishing power is measured only in relative terms.

Fixed Costs
Costs that do not vary with output. Fixed costs can only be avoided if the firm goes out of business.

Fixed Gear
Fishing gear that is stationary after it is deployed (unlike trawl or troll gear which is moving when it is actively fishing). Fixed gear includes gillnets, long lines, pots, traps, and any other gear that is anchored at least at one end.

Fjord
An estuary with a seaward sill that is formed in a deep valley created by a retreating glacier.

Food and Agriculture Organization (FAO)
United Nations organization founded in 1945 with a mandate to raise levels of nutrition and standards of living, to improve agricultural productivity, and to better the condition of rural populations. FAO is active in land and water development, plant and animal production, forestry, fisheries, economic and social policy, investment nutrition, food standards, and commodities and trade.

Food Chain
The transfer of energy from the source in plants through a series of organisms with repeated eating and being eaten. At each transfer, a large proportion of the potential energy is lost as heat. The shorter the food chain (or the nearest the organism is from the beginning of the food chain), the greater the available energy which can be converted in biomass. (see Predator-Prey Relationship, Trophic Level)

Food Security
Freedom from hunger. The capability to produce an adequate amount of food for all consumers at affordable prices.

Footrope
The rope along the bottom of a trawl net's opening. Small footropes can get caught or tangled in rocky reef areas, so regulations that require small footropes protect these rocky areas by encouraging fishermen to fish elsewhere.

Forage Species
Species used as prey by a larger predator for its food. Includes small schooling fishes such as anchovies, sardines, herrings, capelin, smelts, and menhaden, and invertebrates such as squid.

Fork Length
A measurement used frequently for fish length when the tail has a fork shape. Projected straight distance between the tip of the snout and the fork of the tail.

Freedom of Information Act (FOIA)
Federal statute enacted in 1996 giving members of the public the right to request access to Executive Branch records for inspection or copying.

Front
In oceanographic terms, a region of sharp gradient in temperature or salinity, indicating a transition between two current systems or water masses. Intersection between the thermocline (temperature discontinuity) or halocline (salinity discontinuity) and the surface. Fronts are usually associated with high biological activity, high abundance of highly migratory resources (e.g. tunas), and are actively sought as fishing areas. Fronts can be monitored by satellite remote-sensing.

Fully Exploited
Term used to qualify a stock which is probably neither being overexploited nor underexploited and is producing, on average, close to its maximum sustainable yield (MSY). This situation would correspond to fishing at F_MSY (in a classical production model relating yield to effort) or F_MAX (in a model relating yield-per-recruit to fishing mortality).

Gastropods
Snails and other mollusks (e.g. abalone, Queen conch, and cones) that typically possess a coiled dorsal shell and a ventral creeping foot.

Gear
A fishing gear is a tool used to catch fish, such as hook-and-line, trawl net, gillnet, pot, trap, spear, etc.

Gear Conflict
Conflicts between fishing gear on fishing grounds where one type of gear interferes with another type of gear. An example is where mobile trawling gear damages passive gear, such as lobster traps.

Gear Restriction
1. A type of input control used as a management tool whereby the amount and/or type of fishing gear used by fishers in a particular fishery is restricted by law; 2. Limits placed on the type, amount, number, or techniques allowed for a given type of fishing gear.

General Linear Model (GLM)
1. A mathematical formula (model) that relates one biological factor to another. Once a mathematical relationship is established, scientists use the model to predict one factor over another; 2. A statistical procedure similar to an analysis of variance or a multiple regression that is used to estimate the magnitude of the effects of different factors on a variable of interest. GLM's are the tool of choice for standardizing catch per unit effort (CPUE) data in order to obtain indices of abundance. In such applications, the variable of interest is CPUE and the factors are year and perhaps others such as area, gear configuration, etc.; the standardized abundance index of annual abundance would then be given by the parameters associated with the factor, year.

Generation Time
In the context of the National Standard Guidelines, generation time is a measure of the time required for a female to produce a reproductively-active female offspring for use in setting maximum allowable rebuilding time periods. (see National Standard Guidelines)

Genetically Modified Organism
An organism in which humans by means of gene or cell technologies have altered the genetic material. These include the isolation, characterization, and modification of genes and their introduction into living cells or viruses of DNA, as well as techniques for the production of living cells with new combinations of genetic material by the fusion of two or more cells.

Geographic Information System (GIS)
A computer system for storage, analysis, and retrieval of information in which all data are spatially referenced by their geographic coordinates (latitude, longitude). In addition to primary data, such as climatic and soil characteristics, a GIS can be used to calculate derived values such as erosion hazard, forest yield class, or land suitability for specified land-use types. Data are usually derived from maps, and derived values can be printed out as maps.

Geographic Region
With regard to biogeography and species distribution, a region which is separated from an adjacent region by a barrier which is usually impenetrable to many species, limiting their movement or preventing establishment outside their natural geographic range.

Geothermal Vent
Submerged geoform consisting of a vent of hot, mineral-rich water on the ocean floor, generally located on or near spreading oceanic ridges or on the continental margins of subduction trenches.

Ghost Fishing
The accidental capture of aquatic organisms by fishing gear (usually gillnets, or traps, pots, etc.) that has been lost or discarded into the sea and which continues to entangle or trap aquatic animals.

Gillnet
With this type of gear, the fish are gilled, entangled or enmeshed in the netting. These nets can be used either alone or, as is more usual, in large numbers placed in line. According to their design, ballasting and buoyancy, these nets may be used to fish on the surface, in midwater or on the bottom.

Global Positioning System (GPS)
A low cost ($1,000 to $5,000) electronic receiving system for finding three-dimensional coordinates on the earth using satellites.

Gonadosomatic Index (GSI)
A ratio of the weight of a fish's eggs or sperm to its body weight, used to determine the spawning time of a species of fish.

Goods and Services
Any commodities or nonmaterial goods (services) such as assistance or accommodations that yield positive utility.

Goosefish
Scientific name: Lophius americanus; Market name: Monkfish; Vernacular names: Goosefish, Monktails, Angler, Fishing frog, Allmouth, Molligut, Abbot, Sea-devil, Lotte

Governance
1. In a particular sector (e.g. fisheries), a continuing process through which governments, institutions, and stakeholders of the sector and of other interacting sectors elaborate and adopt appropriate policies, plans, and management strategies to ensure sustainable and responsible resource utilization. In the process, conflicting or diverse interests may be accommodated and cooperative action may be taken; 2. The formal and informal arrangements, institutions, and mores which determine how resources or an environment are utilized, how problems and opportunities are evaluated and analyzed, what behavior is deemed acceptable or forbidden, and what rules and sanctions are applied to affect the pattern of resource and environmental use.

Greenland Turbot
Scientific name: Reinhardtius hippoglossoides; Market name: Turbot; Vernacular name: Newfoundland turbot, Turbot, Blue halibut

Gross Economic Benefits
Positive utility gained from the use of a resource prior to netting the costs. (see Net Economic Benefits)

Gross Register Ton (GRT)
A unit of internal volume of a ship, equal to 100 cubic feet. GRT is the total volume or capacity of a vessel.

Groundfish
Collective term loosely applied to most commercially harvested marine fish other than salmonids, scombrids, and clupeids. Although many groundfish are demersal (e.g. yellowtail flounder, yellowfin sole), other species are semidemersal or pelagic (e.g. pollock, cod, haddock).(see Demersal)

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
1. A mathematical formula that describes the increase in length or weight of an individual fish with time; 2. A mathematical description or representation of the size of a living organism at its various ages. The von Bertalanffy growth model is commonly used in fish stock assessments.

Growth Overfishing
1. The situation existing when the rate of fishing is above F_MAX and when fish are harvested before their growth potential is fully reached; 2. When fishing pressure on smaller fish is too heavy to allow the fishery to produce its maximum poundage. Growth overfishing, by itself, does not affect the ability of a fish population to replace itself.

Growth Rate (K)
1. Annual or seasonal. The increase in weight of a fish per year (or season), divided by the initial weight; 2. In fish this is often measured in terms of the parameter K of the von Bertalanffy curve for the mean weight as a function of age.

Guyot
Submerged earthform at depths >200 meters consisting of a flat-topped seamount with a cap of the carbonate remains of a drowned atoll.

Gyre
Large cyclonic current that moves water in a circular pattern from the tropics to the polar seas.

Habitat
1. The environment in which the fish live, including everything that surrounds and affects its life, e.g. water quality, bottom, vegetation, associated species (including food supplies); 2. The locality, site and particular type of local environment occupied by an organism.

Habitat Area(s) of Particular Concern (HAPC)
Subsets of essential fish habitat that serve an important ecological function, are particularly sensitive to human-induced environmental degradation, are particularly stressed by human development activities, or comprise a rare habitat type.

Hadal Zone
Deepest deep bottom area or portion of submerged geoform at depths >7,000 meters.

Haddock
Scientific name: Melanogrammus aeglefinus; Market name: Haddock; Vernacular name: Scrod haddock

Hake
Scientific name: Mercluccius productus; Market names: Whiting or Pacific whiting; Vernacular name: California hake, Pacific hake

Halophytic
Salt-tolerant vegetation.

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.

Harvest Control Rule
Describes how harvest is intended to be controlled by management in relation to the state of some indicator of stock status. For example, a harvest control rule can describe the various values of fishing mortality that will be aimed at for various values of the stock abundance. It formalizes and summarizes a management strategy. Constant catch and constant fishing mortality are two types of simple harvest control rules.

Harvest Guideline
A numerical harvest level that is a general objective, but not a quota. Attainment of a harvest guideline does not require a management response, but does prompt review of a fishery.

Harvest Specifications
The detailed regulations that make up management measures; for example, trawl footrope size, depth limits, net mesh-size, etc.

Harvesting Capacity
The capacity of the fishing fleet to harvest fish, usually expressed in terms of some measure of vessel size, such as gross tonnage, hold capacity, horsepower.

Head Boat
A fishing boat that takes recreational (sport) fishermen out for a fee per person. Different from a charter boat in that people on a head boat pay individual fees as opposed to renting the boat. (see Party Boat)

Head Rope
The length of rope or wire in a trawl to which the top wings and cover netting are attached.

Health
The condition of the marine environment from the perspective of adverse effects caused by anthropogenic (human) activities, in particular habitat destruction, changed sedimentation rates and the mobilization of contaminants. Such condition refers to the contemporary state of the ocean, prevailing trends, and the prognosis for improvement or deterioration of its quality.

Heritage Value
Site possessing historical, archaeological, architectural, technological, aesthetic, scientific, spiritual, social, traditional, or other special cultural significance associated with human activity.

Highgrading
Form of selective sorting of fish in which higher value, more marketable fish are retained and fish that could be legally retained, but are less marketable, are discarded.(see Discard)

High Seas
All waters beyond the Exclusive Economic Zone (EEZ) (>200 nautical miles) of the United States and beyond any foreign nation's EEZ.

High Seas Resources
Resources distributed exclusively in the high seas, i.e. in waters beyond the areas of national jurisdiction (which can be 200 nautical miles or less) excluding species fixed on the continental shelf which remain under the sovereign rights of the coastal states.

Highly Migratory Species
Marine species whose life cycle includes lengthy migrations, usually through the exclusive economic zones of two or more countries as well as into international waters. This term usually is used to denote tuna and tuna-like species, sharks, swordfish, and billfish.

Hook and Line
A type of fishing gear consisting of a hook tied to a line. Fish are attracted by natural bait that is placed on the hook, and are impaled by the hook when biting the bait. Artificial bait (lures) with hooks are often used. Hook-and-line units may be used singly or in large numbers.

Household
All the persons, kin and non-kin, who live in the same dwelling and share income, expenses, and daily subsistence tasks. A basic unit for sociocultural and economic analysis, a household may consist of persons (sometimes one but generally two or more) living together and jointly making provision for food or other essentials elements of livelihood.

Hydrothermal Vent
A place on the seafloor, generally associated with spreading centers, where warm to super-hot, mineral-rich water is released; may support a diverse community of organisms.

Hypersaline
Extremely salty, having much more salt than normal seawater.

Ichthyoplankton
Fish eggs and larvae belonging to the planktonic community.

Incidental Catch
Retained or discarded nontarget species caught when fishing for the primary purpose of catching a different species.

Incidental Take
The "take" of protected species (such as listed salmon, marine mammals, sea turtles, or sea birds) during fishing. "Take" is defined as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or to attempt to engage in any such conduct.

Index of Abundance
A relative measure of the abundance of a stock; for example, a time series of catch per unit effort data.

Indicators
1. A variable, pointer, or index. Its fluctuation reveals the variations in key elements of a system. The position and trend of the indicator in relation to reference points or values indicate the present state and dynamics of the system. Indicators provide a bridge between objectives and action; 2. Signals of processes, inputs, outputs, effects, results, outcomes, impacts, etc., that enable such phenomena to be judged or measured. Both qualitative and quantitative indicators are needed for management learning, policy review, monitoring, and evaluation; 3. In biology, an organism, species, or community whose characteristics show the presence of specific environmental conditions, good or bad.

Indigenous Fishing
Fishing undertaken by peoples native to a land or region.

Indirect Methods
Methods for stock assessment based on fishery-dependent data, such as catch and effort statistics and age structure of the catch.

Individual Fishing Quota (IFQ)
A type of limited entry, an allocation to an individual (a person or a legal entity, e.g. a vessel owner or company) of a right [privilege] to harvest a certain amount of fish in a certain period of time. It is also often expressed as an individual share of an aggregate quota, or total allowable catch