DEFINING FISHERIES: A User's Glossary
by Kenneth J. Roberts
Jerald W. Horst
John E. Roussel
Joseph A. ShephardPublished in 1991 by Louisiana Sea Grant College Program, LouisianaState University, Baton Rouge
INTRODUCTION
The harvest of fish by commercial and recreational fishermen is regulatedby federal and state agencies that develop plans by which to manage fisheryresources. In so doing, agencies seek advice from fishermen and othersinvolved with the fishing industry. Management plans include technicalwords and terms that are difficult to understand. This glossary gives definitionsthat should help fishermen understand the scientific basis of management.Thus, their comments and advice will be more useful in planning and management.
Putting fishery management terms in nonscientific words may make somedefinitions too simple, but the authors sought to get the main idea acrosson each term. Some terms are referred to by scientists as letters or groupsof letters (acronyms) and these are listed at the end of the publicationfor quick reference. The word fish is used throughout, and includes finfishand shellfish species. A mail-in form is provided to identify words andterms that need to be included in a future printing.
A
A See annual mortality.
ABC See allowable biological catch.
AP See advisory panel.
Absolute Abundance The total number of a kind of fish in thepopulation. This is rarely known, but usually estimated from relative abundance,although other methods may be used.
Abundance See relative abundance and absolute abundance.
Advisory Panel (AP) - A group of people appointed by a fisheriesmanagement agency to review information and give advice. Members are usuallynot scientists, but most are familiar with the fishing industry or a particularfishery.
Age Frequency or Age Structure A breakdown of the different agegroups of a kind of fish in a population or sample.
Allocation Distribution of the opportunity to fish among usergroups or individuals. The share a user group gets is sometimes based onhistoric harvest amounts.
Allowable Biological Catch (ABC) A term used by a managementagency which refers to the range of allowable catch for a species or speciesgroup. It is set each year by a scientific group created by the managementagency. The agency then takes the ABC estimate and sets the annual totalallowable catch (TAC).
Anadromous Fish that migrate from saltwater to fresh water tospawn.
Angler A person catching fish or shell fish with no intent tosell. This includes people releasing the catch.
Annual Mortality (A) The percentage of fish dying in one yeardue to both fishing and natural causes.
Aquaculture The raising of fish or shellfish under some controls.Ponds, pens, tanks, or other containers may be used. Feed is often used.A hatchery is also aquaculture but the fish are released before harvestsize is reached.
Artisanal Fishery Commercial fishing using traditional or smallscale gear and boats.
Availability Describes whether a certain kind of fish of a certainsize can be caught by a type of gear in an area.
B
Bag Limit The number and/or size of a species that a person canlegally take in a day or trip. This may or may not be the same as a possessionlimit.
Benthic Refers to animals and fish that live on or in the waterbottom.
Billfishes The family of fish that includes marlins, sailfishand spearfish.
Biological Reference Point Benchmark used to evaluate given levelsof fishing mortality (such as Fmax, F0. 1, FSPR).
Biomass The total weight or volume of a species in a given area.
Bony Fishes Fish that have a bony skeleton and belong to theclass Osteichthyes. Basically, this is all fish except for sharks, rays,skates, hag fish and lampreys.
Bycatch The harvest of fish or shellfish other than the speciesfor which the fishing gear was set. Examples are blue crabs caught in shrimptrawls or sharks caught on a tuna longline. Bycatch is also often calledincidental catch. Some bycatch is kept for sale.
C
C/E See catch per unit of effort.
CPUE See catch per unit of effort .
Capital Stuffing Refers to the investment decisions of commercialfishermen in regard to restrictive regulations. They invest more moneyin fishing capacity to offset regulations that make fishing effort lesseffective.
Catadromous Fish that migrate from fresh water to saltwater tospawn.
Catch The total number or poundage of fish captured from an areaover some period of time. This includes fish that are caught but releasedor discarded instead of being landed. The catch may take place in an areadifferent from where the fish are landed. Note: Catch, harvest, and landingsare different.
Catch Curve A breakdown of different age groups of fish, showingthe decrease in numbers of fish caught as the fish become older and lessnumerous or less available. Catch curves are often used to estimate totalmortality.
Catch (Fishing) Rights A fisheries management agency may developa limited entry program. In some the fishermen are given a share of theallowable catch from a stock of fish. This share might better be viewedas a privilege rather than a "right";.
Catch Per Unit of Effort (CPUE; C/E) The number of fish caughtby an amount of effort. Typically, effort is a combination of gear type,gear size, and length of time gear is used. Catch per unit of effort isoften used as a measurement of relative abundance for a particular fish.
Catch Stream The catch statistics for a kind or stock of fishover a period of time.
Catchability Coefficient (q) The part of a stock that is caughtby a defined unit of effort.
Charter Boat A boat available for hire, normally by a group ofpeople for a short period of time. A charter boat is usually hired by anglers.
Coastal Migratory Pelagic Fishes Several species of fish thatlive in open waters near the coast, grouped together by the Gulf of MexicoFishery Management Council and South Atlantic Fishery Management Councilfor management purposes. This includes king and Spanish mackerel, cobia,dolphin, and little tunny.
Cohort A group of fish spawned during a given period, usuallywithin a year.
Cohort Analysis See virtual population analysis
Commercial Fishery A term related to the whole process of catchingand marketing fish and shellfish for sale.
Common Property Resource A term that indicates a resource ownedby the public. It can be fish in public waters, trees on public land, andthe air. The government regulates the use of a common property resourceto ensure its future benefits.
Compensatory Growth An increase in growth rate shown by fishwhen their populations fall below certain levels. This may be caused byless competition for food and living space.
Compensatory Survival A decrease in the rate of natural mortality(natural deaths) that some fish show when their populations fall belowa certain level. This may be caused by less competition for food and livingspace.
Condition A mathematical measurement of the degree of plumpnessor general health of a fish or group of fish.
Confidence Interval The probability, based on statistics, thata number will be between an up per and lower limit.
Control Date The date often established by the National MarineFisheries Service for a fishery after which new participants are not guaranteeda right to fish.
Council Indicates a regional fishery management group. The FisheryConservation and Management Act of 1976 as amended created the regionalcouncils. For example, the Gulf of Mexico Fishery Management Council developsfishery policies designed to manage those species most often found in Gulffederal waters.
Crowding Externality The impact a fisherman's catch of a specieshas on another fisherman's catch of the same species.
Crustacean A group of freshwater and salt-water animals havingno backbone, with jointed legs and a hard shell made of chitin. Includesshrimp, crabs, lobsters, and crayfish.
Cumulative Frequency Distribution A chart showing the numberof animals that fall into certain categories, for example, the number offish caught that are less than one pound, less than three pounds, and morethan three pounds. A cumulative frequency distribution shows the numberin a category, plus the number in previous categories.
D
Demersal Describes fish and animals that live near water bottoms.Examples are flounder and croaker.
Directed Fishery Fishing that is directed at a certain speciesor group of species. This applies to both sport fishing and commercialfishing.
Disappearance (Z') Measures the rate of decline in numbers offish caught as fish become less numerous or less avail able. Disappearanceis most often calculated from catch curves.
E
EEZ See exclusive economic zone.
EIS See environmental impact statement.
ESO See economics and statistics office.
Economic Efficiency In commercial fishing, the point at whichthe 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.Fish harvesting at the point of economic efficiency produces the maximumeconomic yield. See maximum economic yield and economic rent.
Economic Overfishing A level of fish harvesting that is higherthan that of economic efficiency; harvesting more fish than necessary tohave maximum profits for the fishery.
Economic Rent The total amount of profit that could be earnedfrom a fishery owned by an individual. Individual ownership maximizes profit,but an open entry policy usually results in so many fishermen that profitdecreases. See maximum economic yield.
Economics and Statistics Office (ESO) A unit of the NationalMarine Fisheries Service (NMFS) found in the regional director's office.This unit does some of the analysis required for developing fishery policyand management plans.
Effort The amount of time and fishing power used to harvest fish.Fishing power includes gear size, boat size, and horsepower.
Elasmobranch Describes a group of fish with out a hard bony skeleton,including sharks, skates, and rays.
Electrophoresis A method of determining the genetic differencesor similarities between individual fish or groups of fish by using tissuesamples.
Environmental Impact Statement (EIS) An analysis of the expectedimpacts of a fisheries management plan (or some other proposed action)on the environment.
Equilibrium (Steady State) The condition that exists when fishingpressure remains constant over time.
Escapement The percentage of fish in a particular fishery thatescape from an inshore habitat and move offshore, where they eventuallyspawn.
Euryhaline Fish that live in a wide range of salinities.
Ex-vessel Refers to activities that occur when a commercial fishingboat lands or unloads a catch. For example, the price received by a captainfor the catch is an exvessel price.
Excess Profit A level of profit above normal profit that couldarise from limiting entry to a fishery.
Exclusive Economic Zone (EEZ) All waters from the seaward boundaryof coastal states to 200 nautical miles. This was formerly called the FisheryConservation Zone.
Exploitation Pattern The exploitation rates throughout the lifeof a fish.
Exploitation Rate The probability that a given fish will dieduring the year because of fishing.
Externality See crowding externality and stock externality.
F
F See fishing mortality.
Fmax The level of fishing mortality (rate of removal by fishing)that produces the greatest yield from the fishery.
FCMA See Fishery Conservation and Management Act.
FCZ See fishery conservation zone.
FMC- See fishery management council.
FMP See fishery management plan.
Fecundity A measurement of the egg-producing ability of a fish.Fecundity may change with the age and size of the fish.
Fishery Conservation and Management Act (FCMA) A federal lawthat created the regional councils and is the federal government's basisfor fisheries management in the EEZ. Also known as the Magnuson Act aftera chief sponsor, Senator Warren Magnuson of Washington.
Fishery All the activities involved in catching a species offish or group of species.
Fishery Conservation Zone (FCZ) The area from the seaward limitof state waters out to 200 miles. The term is used less often now thanthe current term, exclusive economic zone.
Fishery Dependent Data Data collected on a fish or fishery fromsport fish men, commercial fishermen, and sea food dealers.
Fishery Independent Data Data collected on a fish by scientistswho catch the fish themselves, rather than depending on fishermen and seafood dealers.
Fishery Management Council (FMC) See council Fishery ManagementPlan (FMP) A plan to achieve specified management goals for a fishery.It includes data, analyses, and management measures for a fishery.
Fishing Effort See effort.
Fishing Mortality (F) A measurement of the rate of removal offish from a population by fishing. Fishing mortality can be reported aseither annual or instantaneous. Annual mortality is the percentage of fishdying in one year. Instantaneous is that percentage of fish dying at anyone time. The acceptable rates of fishing mortality may vary from speciesto species.
Fork Length The length of a fish as measured from the tip ofits snout to the fork in the tail.
G
GLM See general linear model.
GSI See gonosomatic index.
General Linear Model (GLM) A mathematical formula that relatesone biological factor to another. Once a mathematical relationship is established,scientists use the formula to predict one factor over another.
Gonosomatic Index (GSI) The ratio of the weight of a fish's eggsor sperm to its body weight. This is used to de mine the spawning timeof a species of fish.
Groundfish A species or group of fish that lives most of itslife on or near the sea bottom.
Growth Usually an individual fish's increase in length or weightwith time. Also may refer to the increase in numbers of fish in a populationwith time.
Growth Model A mathematical for la that describes the increasein length or weight of an individual fish with time.
Growth Overfishing When fishing pressure on smaller fish is tooheavy to allow the fishery to produce its maximum poundage. Growth overfishing,by itself, does not affect the ability of a fish population to replaceitself.
H
Harvest The total number or poundage of fish caught and keptfrom an area over a period of time. Note that landings, catch, and harvestare different.
Head Boat A fishing boat that takes recreational fishermen outfor a fee per person. Different from a charter boat in that people on ahead boat pay in al fees as opposed to renting the boat.
High Grading The discarding of a portion of a vessel's legalcatch to have a higher or larger grade of fish that bring higher prices.It may occur in quota and nonquota fisheries.
Histogram A method of showing data in a graph. The data appearas bars running up and down (vertical) or sideways (horizontal).
I
ITQ See individual transferable quota.
Incidental Catch See bycatch.
Individual Quota Generally a percentage of the total allowablecatch (TAC) of a fish stock, allocated to an individual or a vessel. Oftenan individual quota is transferable and referred to as an Individual TransferableQuota (ITQ).
Industrial Fishery A fishery for species not directly used forhuman food. An example is menhaden.
Instantaneous Mortality See fishing mortality, natural mortality,and total mortality.
Intrinsic Rate of Increase (z) The change in the amount of harvestablestock. It is estimated by recruitment increases plus growth minus naturalmortality.
Isopleth A method of showing data on a graph which is commonlyused in determining yield-per-recruit.
J
Juvenile A young fish or animal that has not reached sexual maturity.
L
Landings The number or poundage of fish unloaded at a dock bycommercial fishermen or brought to shore by recreational fishermen forpersonal use. Landings are reported at the points at which fish are broughtto shore. Note that landings, catch, and harvest are different.
Latent Species A species of fish that has the potential to supporta directed fishery.
Length Frequency A breakdown of the different lengths of a kindof fish in a population or sample.
Length-Weight Relationship Mathematical formula of the weightof a fish in terms of its length. When only one is known, the scientistcan use this for la to determine the other.
License Limitation Legally restricting the number of commercialfishermen licensed to fish. Often a management agency uses this as a meansof limited entry.
Limited Entry A program that changes a common property resourcelike fish into private property for individual fish men. License limitationand the individual transferable quota (ITQ) are two forms of limited entry.
M
mm See millimeter.
M See natural mortality.
MEY See maximum economic yield.
MRFSS See marine recreational fishery statistics survey.
MSY See maximum sustainable yield.
Magnuson Act See Fishery Conservation and Management Act.
Mariculture The raising of marine finfish or shellfish undersome controls. Ponds, pens, tanks, or other containers may be used, andfeed is often used. A hatchery is also mariculture but the fish are releasedbefore harvest size is reached.
Marine Mammal Animals that live in marine waters and breatheair directly. These include porpoises, whales, and seals.
Marine Recreational Fishery Statistics Survey (MRFSS) An annualsurvey by the National Marine Fisheries Service (NMFS) to estimate thenumber, catch, and effort of recreational fish men. It serves as a basisfor many parts of fisheries management plans.
Mark-Recapture The tagging and releasing of fish to be recapturedlater in their life cycles. These studies are used to study fish movement,migration, mortality, and growth, and to estimate population size.
Maximum Economic Yield (MEY) This is the total amount of profitthat could be earned from a fishery if it were owned by an individual.An open entry policy usually results in so many fish men that profit higherthan opportunity cost is zero. See economic rent.
Maximum Sustainable Yield (MSY) The largest average catch thatcan be taken continually (sustained) from a stock under average environmentalconditions. This is often used as a management goal.
Mean Another word for the average of a set of numbers. Simplyadd up the individual numbers and then divide by the number of items.
Meristics A series of measurements on a fish, such as scale counts,spine counts, or fin ray counts, which are used to separate different populationsor races of fish.
Millimeter (mm) Metric measurement of length that is 1/25 ofan inch long.
Model In fisheries science, a description of something that cannotbe directly observed. Often a set of equations and data used to make estimates.
Mollusk A group of freshwater and saltwater animals with no skeletonand usually one or two hard shells made of calcium carbonate. Includesthe oyster, clam, mussel, snail, conch, scallop, squid, and octopus.
Moratorium The closure of a fishery to participation by new fishermen.Generally, this closure occurs for a specific period of time.
Morphometrics The physical features of fish, for example, coloration.Morphometric differences are sometimes used to identify separate fish populations.
Multiplier A number used to multiply a dollar amount to get anestimate of economic impact. It is a way of identifying impacts beyondthe original expenditure. It can also be used with respect to income andemployment.
N
NMFS See National Marine Fisheries Service.
National Marine Fisheries Service (NMFS) A federal agency-withscientists, research vessels, and a data collection system-responsiblefor managing the nation's saltwater fish. It oversees the actions of theCouncils under the Fishery Conservation and management Act.
National Standards The Fishery Conservation and Management Actrequires that a fishery management plan and its regulations meet sevenstandards. The seven standards were developed to identify the nation'sinterest in fish management.
Natural Mortality (M) A measurement of the rate of removal offish from a population from natural causes. Natural mortality can be reportedas either annual or instantaneous. Annual mortality is the percentage offish dying in one year. Instantaneous is the percentage of fish dying atany one time. The rates of natural mortality may vary from species to species.
Neritic Refers to fish that live in nearshore waters.
Nursery The part of a fish's or animal's habitat where the younggrow up.
O
OY See optimum yield.
Open Access Fishery A fishery in which any person can legallyparticipate.
Opportunity Cost An amount a fisherman could earn for his timeand investment in another business or occupation.
Optimum Yield (OY) The harvest level for a species that achievesthe greatest overall benefits, including economic, social, and biologicalconsiderations. Optimum yield is different from maximum sustainable yieldin that MSY considers only the biology of the species. The term includesboth commercial and sport yields.
Overcapitalization A situation in which there is more harvestingcapacity than is needed to catch the available fish in an economicallyefficient manner.
Overfishing Harvesting at a rate greater than that which willmeet the management goal.
P
Panel See advisory panel.
Pelagic Refers to fish and animals that live in the open sea,away from the sea bottom.
Population Fish of the same species inhabiting a specified areagrouped together for management purposes.
Population Dynamics The study of fish populations and how fishingmortality, growth, recruitment, and natural mortality affect them.
Possession Limit The number and/or size of a species that a personcan legally have at any one time. Refers to commercial and recreationalfishermen. A possession limit generally does not apply to the wholesalemarket level and beyond.
Predator A species that feeds on other species. The species beingeaten is the prey.
Predator-Prey-Relationship The interaction between a species(predator) that eats another species (prey). The stages of each species'life cycle and the degree of interaction are important factors.
Prey A species being fed upon by other species. The species eatingthe other is the predator.
Profit The difference between revenue from sales of the catchand the cost of fishing.
Primary Productivity A measurement of plant production that isthe start of the food chain. Much primary productivity in marine or aquaticsystems is made up of phytoplankton, which are tiny one- celled algae thatfloat freely in the water.
Pulse FishingHarvesting a stock of fish, then moving on to otherstocks or waiting until the original stock recovers.
Put and Take Fishery The placing of hatchery-raised fish in watersto be caught by fishermen. There are few marine fisheries that fit thisdescription. Most cases are found in inland streams and lakes.
Q
q See catchability coefficient.
Quota The maximum number of fish that can be legally landed ina time period. It can apply to the total fishery or an individual fisherman'sshare under an ITQ system. Could also include reference to size of fish.
R
RD See regional director.
RIR See regulatory impact review.
Recreational Fishery Harvesting fish for personal use, fun, andchallenge. Recreational fishing does not include sale of catch.
Recruit An individual fish that has moved into a certain class,such as the spawning class or fishing-size class.
Recruitment A measure of the number of fish that enter a classduring some time period, such as the spawning class or fishing-size class.
Recruitment Overfishing When fishing pressure is too heavy toallow a fish population to replace itself.
Reef Fish Complex A term used by the Gulf of Mexico Fishery ManagementCouncil to describe the many species of fish found around natural reefs,artificial reefs, ledges, and mud lumps. Snappers, groupers, and tilefishare examples.
Regional Director (RD) The person in charge of the National MarineFisheries Service (NMFS) for a given region. The office of the RegionalDirector for the South Atlantic and Gulf of Mexico states is located inSt. Petersburg, Florida.
Regression Analysis A statistical method that estimates any trendthat might exist among important factors. An example in fisheries managementis the link between catch and other factors like fishing effort and naturalmortality.
Regulatory Impact Review (RIR) The part of a federal fisherymanagement plan that describes the impacts resulting from the plan.
Relative Abundance An index of fish population abundance usedto compare fish populations from year to year. This does not measure theactual numbers of fish, but shows changes in the population over time.
Rent See economic rent.
S
s See survival rate.
SAFE See stock assessment and fishery evaluation report.
SEFC See Southeast Fisheries Center.
SPR See spawning potential ratio.
SSBR See spawning stock biomass per recruit.
SSC See scientific and statistical advisory committee.
Scattergram A graph that shows how factors relate to each other.This is visual, not statistical, and is used when it is necessary to comparetwo factors, like fish age and size .
Scientific Assessment Panel A group of biologists, economists,and sociologists put together by a federal fishery management council toreview scientific data on the condition of a stock of fish and the interestsof the fish men and seafood processors who use the stock. Panel membersgenerally come from universities and state and federal fisheries agencies.
Scientific and Statistical Advisory Committee (SSC) A group ofscientific and technical people giving advice to a council.
Secretarial Management Plan A term used to describe a plan developedby the Secretary of the U.S. Department of Commerce in response to an emergencyor a council's failure to act.
Selectivity The ability of a type of gear to catch a certainsize or kind of fish, compared with its ability to catch other sizes orkinds.
Simulation An analysis that shows the production and harvestof fish using a group of equations to represent the fishery. It can beused to predict events in the fishery if certain factors changed.
Size Distribution A breakdown of the number of fish of varioussizes in a sample or catch. The sizes can be in length or weight. Thisis most often shown on a chart.
Slot Limit A limit on the size of fish that may be kept. Allowsa harvester to keep fish under a minimum size and over a maximum size,but not those in between the minimum and maximum.
Social Impacts The changes in people, families, and communitiesresulting from a fishery management decision.
Socioeconomics A word used to identify the importance of factorsother than biology in fishery management decisions. For example, if managementresults in more income fishing, it is important to know how the incomeis distributed between small and large boats or part-time and full-timefishermen.
Southeast Fisheries Center (SEFC) Head-quarters for the scientificstaff of the National Marine Fisheries Service (NMFS) in the South Atlanticand Gulf of Mexico states. The center is located in Miami, Florida, withsmaller laboratories at several other locations.
Spawner-Recruit Relationship The concept that the number of youngfish (recruits) entering a population is related to the number of parentfish (spawners).
Spawning Potential Ratio (SPR) The ratio of the egg-producingability of all the mature fish in a fished stock to the egg-producing abilitythat would exist if the stock were unfished. An SPR per age is sometimesused as a target for managing or rebuilding fisheries stocks.
Spawning Stock Biomass The total weight of the fish in a stockthat are old enough to spawn.
Spawning Stock Biomass Per Recruit (SSBR) The ratio of the totalweight of mature fish in a fished stock to the total weight that wouldexist if the stock were unfished. Frequently, these percentages are usedas target figures for managing or rebuilding fisheries stocks. The percentagesmay change for different species.
Species A group of similar fish that can freely interbreed.
Sport Fishery See recreational fishery.
Standard Length The length of a fish as measured from the tipof the snout to the hidden base of the tail fin rays.
Standing Stock See biomass.
Stock A grouping of fish usually based on genetic relationship,geographic distribution, and movement patterns.
Stock Assessment Group A group of scientists, skilled in thestudy of fish population dynamics put together by a federal fishery managementcouncil to review the scientific data on the condition of a stock of fish.The scientists generally come from universities and state and federal fisheriesagencies.
Stock Assessment and Fishery Evaluation Report (SAFE) A reportthat provides a summary of the most recent biological condition of a stockof fish and the economic and social condition of the recreational fishermen,commercial fishermen, and seafood processors who use the fish. The reportprovides information to the federal fishery management councils for determiningharvest levels.
Stock Externality The impact on a nontargeted stock of fish caughtwhen a targeted group of fish is harvested.
Stock-Recruit Relationship See spawner-recruit relationship.
Stressed Area An area in which there is special concern regardingharvest, perhaps because the fish are small or because harvesters are inconflict.
Surplus Production Model A model that estimates the catch ina given year and the change in stock size. The stock size could increaseor decrease depending on new recruits and natural mortality. A surplusproduction model estimates the natural increase in fish weight or the sustainableyield.
Survival Rate (s) The number of fish alive after a specifiedtime, divided by the number alive at the beginning of the period.
Sustainable Yield Amount of harvest (yield) that can be removedfrom a population while allowing the population to perpetuate itself intothe future given average environmental conditions.
T
TAC See total allowable catch.
TIP See trip interview program.
Territorial Sea The area from average low-water mark on the shoreout to three miles for the states of Louisiana, Alabama, and Mississippi,and out to nine miles for Texas and the west coast of Florida. The shoreis not always the base line from which the three miles are measured. Insuch cases, the outer limit can extend farther than three miles from theshore.
Total Allowable Catch (TAC) The annual recommended catch fora species or species group. The regional council sets the TAC from therange of the allowable biological catch.
Total Allowable Level of Foreign Fishing (TALFF) The portionof the annual optimum yield of a fishery that will not be harvested byUnited States vessels.
Total Length The length of a fish as measured from the tip ofthe snout to the tip of the tail.
Total Mortality (Z) A measurement of the rate of removal of fishfrom a population by both fishing and natural causes. Total mortality canbe reported as either annual or instantaneous. Annual mortality is thepercentage of fish dying in one year. Instantaneous mortality is that percentageof fish dying at any one time. The rate of total mortality may vary fromspecies to species.
Trip Interview Program (TIP) A management agency's face-to-faceinterviewing of commercial fishermen to collect data. Length of trip, location,catch, and other data are collected.
U
Underutilized Species A species of fish that has potential forlarge additional harvest.
Unit Stock A population of fish grouped together for assessmentpurposes which may or may not include all the fish in a stock.
V
VPA See virtual population analysis.
Virgin Stock A stock of fish with no commercial or recreationalharvest. A virgin stock changes only in relation to environmental factorsand its own growth, recruitment and natural mortality.
Virtual Population Analysis (VPA) A type of analysis that usesthe number of fish caught at various ages or lengths and an estimate ofnatural mortality to estimate fishing mortality in a cohort. It also providesan estimate of the number of fish in a cohort at various ages.
W
Windfall Profit A one-time gain arising from limiting entry.It comes from the increased value of a license or individual quota whenthe fishery is limited. It can only be obtained by a fisherman's sellinghis fishing privilege.
Y
Year-Class The fish spawned and hatched in a given year, a "generation";of fish.
Yield The production from a fishery in terms of numbers or weight.
Yield Per Recruit A model that estimates yield in terms of weight,but more often as a per age of the maximum yield, for various combinationsof natural mortality, fishing mortality and time exposed to the fishery.
Z
z See intrinsic rate of increase.
Z See total mortality.
Z' See disappearance.
Send to suggestions for other words or terms that should be definedin later editions of this glossary to: Defining Fisheries, Sea Grant CommunicationsOffice, Louisiana Sea Grant College Program, Louisiana State University,Baton Rouge, LA 70803-7507
First Edition, July 1991 Revised, May 1995 Louisiana Sea Grant CollegeProgram Louisiana State University Baton Rouge, Louisiana 70803-7507 Theresearch that resulted in this publication was supported by the LouisianaSea Grant College Program of Louisiana State University.
Louisiana Sea Grant is a part of the National Sea Grant College Programmaintained by the National Oceanic and Atmospheric Administration, U.S.Department of Commerce, and is also supported by the state of Louisiana.
ACRONYMS
A Annual Mortality
ABC Allowable Biological Catch
AP Advisory Panel
C/E Catch Per Unit of Effort
CPUE Catch Per Unit of Effort
EEZ Exclusive Economic Zone
EIS Environmental Impact Statement
ESO Economics and Statistics Office
F Fishing Mortality
FCMA Fishery Conservation and management Act
FCZ Fishery Conservation Zone
FMC Fishery Management Council
FMP Fishery Management Plan
GLM General Linear Model
GSI Gonosomatic Index
ITQ Individual Transferable Quota
mm Millimeter
M Natural Mortality
MEY Maximum Economic Yield
MRFSS Marine Recreational Fishery Statistics Survey
MSY Maximum Sustainable Yield
NMFS National Marine Fisheries Service
OY Optimum Yield
q Catchability Coefficient
RD Regional Director
RIR Regulatory Impact Review
s Survival Rate
SAFE Stock Assessment and Fishery Evaluation Report
SEFC Southeast Fisheries Center
SPR Spawning Potential Ratio
SSBR Spawning Stock Biomass Per Recruit
SSC Scientific and Statistical Advisory Committee
TAC Total Allowable Catch
TALFF Total Allowable Level of Foreign Fishing
TIP Trip Interview Program
VPA Virtual Population Analysis
z Intrinsic Rate of Increase
Z Total Mortality
Z' Disappearance