Glossary
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | view all
Salmonid
Fish of the family Salmonidae, including salmon and steelhead.
Sample A
proportion or a segment of a fish stock which is removed for study, and is assumed to be representative of the whole. The greater the effort, in terms of both numbers and magnitude of the samples, the greater the confidence that the information obtained is a true reflection of the status of a stock (level of abundance in terms of numbers or weight, age composition, etc.)
Sampling design
The sampling design of a scientific survey refers to the statistical techniques and methods adopted for selecting a sample and obtaining estimates of the survey variables from the selected sample
Sand
Small substrate particles, generally referring to particles less than 2 mm in diameter. Sand is larger than silt and smaller than cobble or rubble.
Scute
An extendal bony plate, usually keeled.
Seasonal Total Mortality Rate
See Annual Total Mortality Rate.
Sediment
The organic material that is transported and deposited by wind and water.
Selective fishery
A fishery that allows the release of non-targeted fish stocks/runs, including unmarked fish of the same species.
Self-sustaining population
A population of salmonids that exists in sufficient numbers to replace itself through time without supplementation with hatchery fish. It does not necessarily produce surplus fish for harvest.
Semelparous
Species that reproduce only once during their lifetime.
Silt
Substrate particles smaller than sand and larger than clay.
Smolt
Refers to the salmonid or trout developmental life stage between parr and adult, when the juvenile is at least one year old and has adapted to the marine environment.
Smoltification
Refers to the physiological changes anadromous salmonids and trout undergo in freshwater while migrating toward saltwater that allow them to live in the ocean.
Sockeye salmon
An anadromous salmonid of the genus Oncorhynchus and species nerka. Also known as red or blueback salmon. (See Kokanee).
Spawn
The act of reproduction of fishes. The mixing of the sperm of a male fish and the eggs of a female fish.
Spawner
Sexually mature individual.
Spawning stock
Mature part of a stock responsible for the reproduction. Strictly speaking, the part of an overall stock having reached sexual maturity and able to spawn. Often conventionally defined as the number of biomass of all individuals beyond the "age at first maturity" of size at first maturity (i.e. beyond the age or size class in which 50% of the individuals are mature.
Spawning stock biomass
The total weight of all sexually mature fish in the population. This quantity depends on year class abundance, the exploitation pattern, the rate of growth, fishing and natural mortality rates, the onset of sexual maturity and environmental conditions.
Spawning stock biomass-per-recruit
The expected lifetime contribution to the spawning stock biomass for a recruit of a specific age (e.g., per age 2 individual). For a given exploitation pattern, rate of growth, and natural mortality, an expected equilibrium value of SSB/R can be calculated for each level of F. A useful reference point is the level of SSB/R that would be realized if there were no fishing. This is a maximum value for SSB/R, and can be compared to levels of SSB/R generated under different rates of fishing. For example, the maximum SSB/R for Georges Bank haddock is approximately 9 kg for a recruit at age 1.
Species
A taxon of the rank of species; in the hierarchy of biological classification the category below genus; the basic unit of biological classification; the lowest principal category of zoological classification.
Spine
A single, median supporting element of a fin, usually stiff. Distinguished from a ray in that it is single, median, never branched or jointed.
Standard length
The straight distance between the tip of the snout and the base of the caudal fin rays.
Standardization
The procedure of maintaining methods and equipment as constant as possible.
Status of exploitation
An appraisal of exploitation is given for each stock discussed in the Species Synopsis section using the terms unknown, protected, not exploited, underexploited, moderately exploited, fully exploited, and over-exploited. These terms describe the effect of current fishing effort on each stock, and is based on current data and the knowledge of the stocks over time.
Stock
[Individuals that share] a particular migration pattern, specific spawning grounds, and subject to a distinct fishery. A fish stock may be treated as a total or a spawning stock. Total stock refers to both juveniles and adults, either in numbers or by weight, while spawning stock refers to the numbers or weight of individuals which are old enough to reproduce. [This level of classification typically subsumes race, metapopulation, subpopulation, and demes. Used in the context of management.]
Stock A
Part of a fish population usually with a particular migration pattern, specific spawning grounds, and subject to a distinct fishery. A fish stock may be treated as a total or spawning stock. Total stock refers to both juveniles and adults, either in numbers or by weight, while spawning stock refers to the numbers or weight of individuals which are old enough to reproduce. This level of classification typically subsumes race, metapopulation, subpopulation, and demes. Used in the context of management.
Stock assessment
The process of collecting and analyzing biological and statistical information to determine the changes in the abundance of fishery stocks in response to fishing, and, to the extent possible, to predict future trends of stock abundance. Stock assessments are based on resource surveys; knowldege of the habitat requirements, life history, and behavior of the species; the use of environmental indices to determine impacts on stocks; and catch statistics. Stock assessments are used as a basis to assess and specify the present and probably future condition of a fishery.
Stock origin
The genetic history of a stock.
Stray
An individual that breeds in a population other than that of its parents.
Stray rate
The proportion of a population that consists of strays.
Straying
A natural phenomena of adult spawners not returning to their natal stream, but entering and spawning in some other stream.
Subabdominal pelvic fin
Said of pelvic fins when placed forward on abdomen but not attached internally to pectoral girdle.
Subadult
A developmental life stage when fish exhibit most but not all traits of an adult fish.
Sub-Population
A well-defined set of interacting individuals that compose a proportion of a larger, interbreeding metapopulation.
Subspecies
A population of a species occupying a particular geographic area, or less commonly, a distinct habitat, capable of interbreeding with other populations of the same species.
Substrate
The material which comprises a stream bottom.
Subtidal zone
Shallow-water areas below mean low water.
Subyearling
A developmental life stage of fish that are less than one year old.
Success (of fishing)
Catch per unit of effort.
Supplementation
The use of artificial propagation to maintain or increase natural production while maintaining the long-term fitness of the target population, and keeping the ecological and genetic impacts to non-target populations within specified biological limits.
Supramaxilla
A small bone attached to the posterior end of the maxilla, dorsally.
Surplus production
Production of new weight by a fishable stock, plus recruits added to it, less what is removed by natural mortality. This is usually estimated as the catch in a given year plus the increase in stock size (or less the decrease). Also called natural increase, sustainable yield, equilibrium catch.
Survival rate
Number of fish alive after a specified time interval, divided by the initial number. Usually on a yearly basis.
Swim-up fry
A salmonid fry that is swimming in the water column in search for food.