Review of Northeast Fishery Stock Assessments (1998)

ABC (acceptable biological catch):

Maximum amount of fish stock that could be harvested without adversely affecting recruitment or other biological components of the stock. The ABC level is typically higher than the total allowable catch.

ACFM (Advisory Council on Fisheries Management):

An ICES advisory body. ACFM serves as a review panel, formulating advice based on assessments and draft advice from area-based assessment working groups. In addition to the assessment working groups, ACFM coordinates the work of methodologically oriented working groups.

ADAPT (ADAPTive framework):

Age-structured assessment model used to estimate the abundance of fish stocks. The ADAPT technique is used to tune or modify the VPA model to minimize the discrepancy between empirical and simulated values of variables.

Amendment 4:

Amendment to the Northeast Multispecies Fisheries Management Plan enacted in 1991 that extended restrictions on minimum mesh sizes and closed areas for a number of groundfish species.

Amendment 5:

Amendment to the Northeast Multispecies Fisheries Management Plan enacted in 1994 that required extensive new regulations on minimum mesh sizes, minimum size limits, closed areas, new fishing permits, and logbook reporting. This amendment had the objective of reducing the fishing effort on cod, haddock, and yellowtail flounder stocks by 50% over five years (1999) based on 1993 levels. Amendment 5 established a days at sea program to reduce fishing effort.

Amendment 6:

Amendment to the Northeast Multispecies Fisheries Management Plan enacted in 1994 as a secretarial amendment to the plan to extend emergency regulations concerning the possession limit for haddock, limits on scallop vessels landing haddock, and modifications to closed-area regulations.

Amendment 7:

Amendment to the Northeast Multispecies Fisheries Management Plan enacted in 1996 to broaden and reinforce regulations enacted under Amendment 5. Amendment 7 extended closed areas and times, minimum size limits, set target TACs for species, established fishing mortality goals, set up a multispecies monitoring committee, and increased the fishing effort reduction goals to a 50% reduction within two years (1997) based on 1993 levels.

BMV:

Type of trawl door used in early surveys by the United States. The BMV design, originally of Norwegian origin, was replaced by Portuguese polyvalent doors in 1985.

CAFSAC (Canadian Atlantic Fisheries Scientific Advisory Committee):

Advisory body formed in 1977 to provide peer-reviewed scientific advice for the management of Canadian groundfish stocks.

Catchability/availability:

Vulnerability of fish to capture by survey gear or fishing gear. The behavior, location, size, and abundance of fish at certain times may affect their vulnerability to capture. The type of vessel or fishing gear used and the competence of a fishing crew may also affect catchability.

Catch at age:

Number or mass of fish from each cohort captured by a fishery for each year.

Coefficient of variation:

Degree of variation, or distribution, of probabilities around a mean value. A high coefficient of variance is indicative of wide variation in the data being analyzed. Coefficient of variation is typically measured as percentage deviation above and below a mean value.

Cohort:

Fish born in a given year. (see Year class).

Compensation:

Decrease in number of recruits per spawner as spawning stock biomass increases.

CPUE (Catch per unit effort):

Weight of fish harvested for each unit of effort expended by vessels in the fishery. CPUE can be expressed as weight of fish captured per fishing trip, per hour spent at sea, or through other standardized measures.

Days absent:

The amount of time, or number of days, a vessel is away from port. Time spent fishing, steaming to fishing grounds, or other non-fishing activities are included.

DAS (days at sea):

Fishery effort control program that establishes a limit on the number of fishing days that a vessel may participate in fisheries included in the Northeast Multispecies Fishery Management Plan. The number of days a vessel may fish is determined based on past participation in the fishery (individual days at sea), or a predetermined value for the fleet (fleet days at sea). The amount or time that qualifies as a day at sea includes time spent engaged in fishing or fishing related activities.

Depensation:

A reduction in per capita productivity at low stock sizes.

Depensatory model:

A model that exhibits depensation in the spawner-recruit relationship.

DFO (Department of Fisheries and Oceans):

Federal agency in Canada responsible for management of fisheries in Canadian federal waters.

EEZ (exclusive economic zone):

Zone extending from the shoreline out to 200 nautical miles in which the country owning that shoreline has the exclusive right to conduct certain activities such as fishing. In the United States, the EEZ is split into state waters (typically from the shore out to 3 nautical miles) and federal waters (typically from 3 to 200 nautical miles).

EFI (exploitation fraction index):

The ratio of the catch to the survey index of abundance. This index is independent of the assessment model, being based only on data. It is an index because the survey index is used rather than a survey estimate of total abundance.

F (fishing mortality):

Instantaneous mortality rate due to fishing. F combined with the natural mortality rate (M) is the total instantaneous mortality rate for a given stock (Z).

F_0.1:

Fishing mortality rate at which an increase in fishing mortality produces a 10 percent increase in yield per recruit relative to 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_max:

Rate of fishing mortality that produces the maximum yield per recruit; The point beyond which growth overfishing occurs.

F_MSY:

Fishing mortality rate that produces the maximum sustainable yield.

Fishery Management Councils:

Eight regional fishery management councils are mandated in the Magnuson-Stevens Fishery Conservation and Management Act responsible for developing fishery management plans for fisheries in federal waters. Councils are composed of voting members from NMFS, state fishery managers, and individuals selected by governors of the coastal states. Nonvoting members include the U.S. Coast Guard, the U.S. Fish and Wildlife Service, and other federal officials. Regional councils exist for the Caribbean, Gulf of Mexico, Mid-Atlantic, New England, North Pacific, Pacific, South Atlantic, and the Western Pacific regions.

FMP (fishery management plan):

Management plan for fisheries operating in the federal EEZ produced by regional fishery management councils and submitted to the Secretary of Commerce for approval. These plans must meet certain mandatory requirements in the Magnuson-Stevens Fishery Conservation and Management Act before they can be approved or implemented.

FRCC (Fisheries Resource Conservation Council):

Committee composed principally of fishing industry representatives and academics nominated by the Canadian Minister of Fisheries and Oceans. The FRCC provides management advice to the Minister.

Growth overfishing:

Level of fishing mortality at which fish are captured before they achieve the maximum yield in mass due to growth. Growth overfishing occurs when fishing mortality is greater than F_max.

ICES (International Council for the Exploration of the Sea):

International body established in 1902. ICES is a scientific forum for the exchange of information and ideas on the sea and its living resources and for the promotion and coordination of marine research by scientists in its member countries. Membership has increased from the original 7 countries in 1902 to the present 19 countries.

ICNAF (International Commission for Northwest Atlantic Fisheries):

Fishery management organization founded by the United States and Canada in 1949 for joint scientific and management measures affecting certain groundfish stocks. ICNAF later evolved into NAFO.

Interim measures:

Effort control measures enacted by the NEFMC in the early and mid 1980s to replace the FMP enacted in 1978. These measures included indirect controls of fishing effort such as minimum mesh and fish size restrictions.

ITQ (Individual Transferable Quota):

Fishery management tool used in eastern Canada and other parts of the world that allocates a certain portion of the TAC to individual vessels, or fishermen, based on initial qualifying criteria. This allocation can be transferred or sold.

IWC (International Whaling Commission):

International commission responsible for regulation of commercial, subsistence, and scientific whaling among member countries. IWC also conducts stock assessments of whale stocks and establishes quotas for subsistence and scientific harvests.

LPUE (landings per unit effort):

Means of quantifying the CPUE. LPUE is the amount, or biomass, of fish landed per given unit of measure, typically measured on a per-trip or per-day basis.

M (natural mortality):

The instantaneous mortality in a fish stock caused by predation, pollution, or other factors not related to fishing.

MMC (Multispecies Monitoring Committee):

Committee established under Amendment 7 to review the amendment's effectiveness in meeting fishing mortality and stock rebuilding goals. The MMC is composed of staff from fishery management councils, NMFS scientists, state fishery officials, and industry representatives.

MRFSS (Marine Recreational Fisheries Statistics Survey):

Primary source of marine recreational data for the New England region. MRFSS is operated by NMFS with the cooperation of coastal states. MRFSS is a design-based survey that produces estimates of total effort and catch in directed recreational fisheries.

M-SFCMA (Magnuson-Stevens Fishery Conservation and Management Act):

Federal legislation responsible for establishing the regional fishery management councils and the mandatory and discretionary guidelines for federal fishery management plans. This legislation was originally enacted in 1976 as the Fishery Management and Conservation Act; its name was later changed to the Magnuson Fishery Conservation and Management Act, and in 1996 was renamed the Magnuson-Stevens Fishery Conservation and Management Act.

MSY (maximum sustainable yield):

Largest average catch that can be captured from a stock under existing environmental conditions on a sustainable basis.

NAFO (Northwest Atlantic Fisheries Organization):

Multinational fishery management organization. Since 1979, NAFO has regulated the harvesting of certain groundfish stocks in the NAFO Regulatory Area outside Canada's EEZ. NAFO establishes total allowable catches and sets quotas and conservation measures. The 15 member states of NAFO are Bulgaria, Canada, Cuba, Denmark (for the Faroe Islands and Greenland), Estonia, the European Union (including Spain and Portugal) Iceland, Japan, Korea, Latvia, Lithuania, Norway, Poland, Romania, Russia, and the United States.

NEFMC (New England Fishery Management Council):

One of eight regional councils mandated in the Magnuson-Stevens Fishery Conservation and Management Act to develop management plans

for fisheries in federal waters. NEFMC develops fishery management plans for fisheries off Maine, New Hampshire, Massachusetts, Connecticut, and Rhode Island. It is comprised of voting members from NMFS, state fishery managers, and individuals selected by governors of the five states. Nonvoting members include the U.S. Coast Guard, the US Fish and Wildlife Service, and other federal officials.

NEFSC (Northeast Fisheries Science Center):

Regional science center operated by NMFS to conduct fishery science in the northeastern United States, including the NEFMC region.

NMFS (National Marine Fisheries Service):

Federal agency within NOAA charged with overseeing the management and regulation of federal fisheries.

NOAA (National Oceanic and Atmospheric Administration):

Federal agency within the Department of Commerce responsible for overseeing oceanographic and atmospheric science and regulation. NMFS is part of NOAA.

R (recruitment):

Number, or percentage, of fish that survive from birth to a specific age or size. The specific size or age at which recruitment is measured may correspond to when the fish first become vulnerable to capture in a fishery or when the number of fish in a cohort can be estimated reliably by stock assessment techniques.

R/SSB (recruitment/spawning stock biomass):

Number of fish recruited into a fishery from a given mass of spawning fish, usually expressed as number of recruits per kilogram of mature fish in a given stock. This ratio can be computed for each year class and is often used as an index of prerecruit survival. High R/SSB in a given year indicates an above-average recruitment of young fish per unit of biomass compared to other year classes.

RAP (Regional Advisory Process):

Canadian stock assessment review process involving federal, provincial, and academic scientists, and possibly fishery managers, fishers, and processors. RAP generates a consensus stock status report presented to the FRCC.

Recruitment overfishing:

Level of fishing mortality at which the recruitment of fish to the spawning stock biomass is significantly reduced. Recruitment overfishing is characterized by a decreasing proportion of older fish in the fishery and consistently low average recruitment over time.

SARC (Stock Assessment Review Committee):

U.S. committee composed of scientists from NMFS, the appropriate regional council, and other academic scientists. SARC reviews stock assessments and related documents produced in the SAW, develops management advice, and agrees on working papers to be published.

SAW (Stock Assessment Workshop):

Workshop responsible for producing the initial stock assessment documents used for formulating management advice. SAW is composed of scientists from NMFS, DFO, and NEFSC involved in conducting the surveys and other data analysis used in stock assessment reports.

SNE:

Southern New England.

SPA (sequential population analysis):

Retrospective analysis of the number of fish alive in each cohort for each past year. SPA relies on a relationship that the number of fish alive in each cohort at the beginning of next year can be calculated from the number alive this year reduced by the fishing mortality and the natural mortality of that cohort for the present year. This method requires catch-at-age data. SPA is similar to VPA; however, it allows fishing mortality and natural mortality to vary between years and with the age of the fish.

SSB (spawning stock biomass):

Total mass of all sexually mature fish in a stock.

SSB/R (spawning stock biomass per recruit):

Average expected contribution to spawning stock biomass for each recruit during its lifetime. SSB/ R is calculated over the life span of the year class of the recruit according to a particular schedule of fishing mortalities. The exploitation pattern, rate of growth, and natural mortality rate of the recruit are usually assumed to be constant.

SSC (statistical and scientific committee):

Fishery management advisory body composed of federal, state, and academic scientists that provides scientific advice to a fishery management council.

TAC (total allowable catch):

Total catch permitted to be caught from a stock in a given time period, typically a year. In the United States, this level is determined by fishery management councils in consultation with NMFS. Typically, this level is lower than the acceptable biological catch.

VPA (virtual population analysis):

Retrospective analysis of the number of fish alive in each cohort for each past year. VPA relies on a relationship that the number of fish alive in each cohort at the beginning of next year can be calculated from the number alive this year reduced by the fishing mortality and the natural mortality of that cohort for the present year. This method requires catch-at-age data.

Year class:

Fish of a given species spawned or hatched in a given year (see Cohort); a three-year-old fish caught in 1998 would be a member of the 1995 year class.

Yield per recruit:

Expected yield in mass from an individual fish over its life span. Yield per recruit is sometimes used to calculate ABCs and TACs.

Z (total mortality):