The next comprehensive benchmark stock assessment of Atlantic Coastal striped bass is due out this month from the Atlantic States Marine Fisheries Commission (ASMFC) at its annual winter meeting, which is held from February 5-7 in Arlington, VA. Jim Hutchinson, Jr. breaks down some of the nitty gritty of what’s going on with striped bass in his feature article this month, and you’ll be sure to see some updates on both at www.TheFisherman.com and on our Facebook page in the coming days and weeks, so I won’t dive into the subject just yet. Instead, I figured I’d help get some definitions for you on a few of the terms of which you are certain to hear thrown around this month like we all know what they mean. Heck, I even find myself using these terms at times without a complete grasp of their true meaning. I cherry-picked these from the “Guide to Fisheries Science and Stock Assessments” which can be found online in its entirety at http://www.asmfc.org/files/Science/GuideToFisheriesScienceAndStockAssessments.pdf.
Abundance – The total number of fish in a population.
Age class – All of the individuals in a given stock spawned or hatched in the same year; also known as ‘year class’ or ‘cohort.’
Anadromous – Species inhabiting brackish and marine waters for most of their lives, but returning to freshwater to spawn.
Biological reference point (BRP) – A particular value of stock size, catch, fishing effort, or fishing mortality that may be used as a measure of stock status or management plan effectiveness. BRPs can be categorized as limits, targets, or thresholds depending on their intended use.
Biomass – The total weight of a stock of fish or a defined stock subunit such as spawning females.
Catch – The total number or weight of fish captured, including fish that are both retained and discarded. Note: catch, harvest, and landings are different terms with different definitions.
Catch and release mortality – Death of a fish from the practice of catch and release in the recreational fishery. The reasons for catching and releasing a fish can vary: the fish may not be of legal size, it may be out of season, or it may be caught and released simply as sport.
Exclusive economic zone (EEZ) – U.S. federal waters that extend from 3 to 200 miles from shore. The U.S. has sole management authority of the natural resources found therein.
Fecundity – The number of eggs produced per female per unit time (e.g., per spawning season).
Fishery – (1) One or more stocks of fish that are treated as a unit for conservation and management purposes and identified on the basis of geographical, biological, technical, commercial, recreational or economic characteristics; and (2) any fishing for such stocks.
Fisheries management – The process by which decisions are made to determine the status and either the exploitation or conservation of a fishery resource. Fisheries management decisions require input on fisheries biology and stock status information, the socioeconomic needs of recreational and commercial fishermen, food web and predator/prey relationships, habitat needs and law enforcement considerations.
Fishery management plan – A plan to achieve specified management goals for a fishery, including data, analysis and management measures for a fishery.
Harvest – The total number or poundage of fish caught and kept from an area over a period of time. Note that catch, harvest and landings are different.
Interstate Fisheries Management Program (ISFMP) – An ASMFC program dedicated to the development and maintenance of interstate fisheries management plans for 22 species groups.
Juvenile – A young fish, usually resembling an adult in appearance that has not yet become sexually mature.
Juvenile abundance index (JAI) – A measure of the relative abundance of juveniles in a stock that may serve as an indication of reproductive success. For some species, the JAI may predict future adult abundance.
Landings – The number or weight of fish brought to dock (commercial) or shore (recreational). Landings are reported at the points at which fish are brought to shore.
Maturity – The age or size at which a species is able to reproduce.
Maximum Sustainable Yield (MSY) – The largest average catch that can be taken from a stock over time under existing environmental conditions without negatively impacting the reproductive capacity of the stock.
Mortality – The rate at which fish die, expressed either as an annual percentage or instantaneous rate (the portion of the stock dying within each small amount of time). Instantaneous rates are used in most stock assessment modeling equations. Fishery scientists estimate several different types of mortality to evaluate the status of fish stocks, and some mortality rates serve as biological reference points.
Overfishing – Harvesting from a stock at a rate greater than the stock’s reproductive capacity to replace fish removed through harvest.
Peer review – The process of having experts provide an independent judgment of the value and appropriateness of the science and methods used to produce a stock assessment.
Population – All individuals of the same species occupying a defined area during a given time.
Population biomass – The total biomass of a population.
Recruit – An individual fish that has entered a defined group through spawning, growth, or migration. Fish recruit to the spawning stock when they become sexually mature. Fish recruit to the fishery when they reach the minimum legal size.
Recruitment – A measure of the weight or number of fish that enter a defined portion of the stock, such as the spawning stock or fishable stock.
Relative Abundance – An index of fish population abundance used to compare fish populations from year to year.
Spawning stock – The female portion of a fish stock that is mature.
Spawning stock biomass – The total weight of the mature females within a stock of fish; frequently used instead of total biomass as a better measure of the ability of a stock to replenish itself.
Stock – A group of fish of the same species that behave (migrate, spawn) as a unit and are genetically unique.
Stock assessment – An evaluation of a stock, including age and size composition, reproductive capacity, mortality rates, stock size and recruitment.
Target (biological reference point) – Benchmarks used to guide management objectives that should not be exceeded on average in order to achieve a desirable outcome (e.g., a sustainable stock). Various levels of fishing mortality (F) and spawning stock biomass (SSB) are commonly defined targets.
Threshold (Biological Reference Point) – Benchmarks used to guide management objectives that represent critical levels not to be crossed. If crossed, the sustainability of the stock is threatened. When on the safe side of a threshold, we expect to maintain a healthy, reproductive fishery. If on the other side of a threshold, the stock is at risk of collapse. Various levels of fishing mortality (F) and spawning stock biomass (SSB) are commonly defined thresholds.
Total allowable catch (TAC) – The annual catch recommended by a management authority for a species or group of species.
Uncertainty – The degree of imperfect knowledge in fisheries analyses due to several underlying factors that go into stock assessments, and in subsequent estimation of reference points provided to management. Managers should consider the degree of uncertainty when developing management strategies.
Year class – All of the individuals in a given stock spawned or hatched in the same year; also known as an ‘age class’ or ‘cohort.’
Young-of-the-year (YOY) – An individual fish in its first year of life; for most species, YOY are juveniles.