The online resource for Ontario’s Fisheries Professionals since 2002

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Glossary of Terms

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Aboriginal Fishery:  The harvesting of fish by aboriginal peoples for food, cultural or ceremonial purposes.

Acid Rain:  Rain that has a pH below the natural range of 5.6 to 5.8. It is caused by the release of oxides of sulphur and nitrogen to the atmosphere through the combustion of fossil fuels.

Adult:  Sexually mature fish.

AFS Status:  Classification assigned to imperiled North American freshwater and diadromous fishes by the American Fisheries Society Endangered Species Committee. The classification considers continental fishes native to Canada, Mexico, and the United States, and evaluates their conservation status and the major threats impacting these taxa.

Status Categories and Abbreviations

Endangered (E): A taxon that is in imminent danger of extinction throughout all or extirpation from a significant portion of its range.

Threatened (T): A taxon that is in imminent danger of becoming endangered throughout all or a significant portion of its range.

Vulnerable (V): A taxon that is in imminent danger of becoming threatened throughout all or a significant portion of its range. This status is equivalent to "Special Concern" as designated by many governmental agencies.

Extinct (X): A taxon of which no living individual has been documented in its natural habitat for 50 or more years. Two additional subcategories of extinction are recognized.

Possibly Extinct (Xp): A taxon that is suspected to be extinct as indicated by more than 20 but fewer than 50 years since individuals were observed in nature.

Extirpated in Nature (Xn): Where all populations of a taxon are presumed to have perished in natural habitats, but reproducing individuals are currently maintained in captivity.

Listing Criteria

(1): Present or threatened destruction, modification, or reduction of a taxon's habitat or range including sedimentation, chemical pollution, dewatering, and anthropogenic modifications to natural channels or flow regimes.

(2): Over-exploitation for commercial, recreational, scientific, or educational purposes; intentional eradication with ichthyocides; or indirect impacts of fishing pressure such as reduction or loss of host fish populations required by parasitic lampreys.

(3): Disease or parasitism.

(4): Other natural or anthropogenic factors that affect a taxon's existence, including impacts of nonindigenous organisms, hybridization, competition, and/or predation.

(5): Occurs in a narrowly restricted range.

Age:  Length of existence usually measured in years.

Ammocoete:  Sexually immature (larval) lamprey.

Amphidromous:  Species that moves between freshwater and marine environments for reasons other than, or in addition to, spawning.

Anadromous:  Species that is spawned and spends its early life in freshwater but migrates to a marine environment, to feed, grow and attain sexual maturity, before returning to freshwater to spawn.

Anthropogenic:  Made or caused by human activities.

Aquatic Vegetation:  Plant life growing in or near the water, excluding algae. Often referred to as aquatic macrophytes.

Artificial Hybrid:  The progeny of crossbreeding between species that does not typically occur in nature.

Backwater:  Calm stream habitat at the edges of a riffle or run; marginal, partly enclosed portion of a pool.

Bait Fish:  Species that is used by anglers to catch sport fish.

Baitfish Introduction:  A method by which fish (usually small minnows) intended to be used as bait, are released or escape into waters, usually as a result of angling activities.

Ballast Water:  Water contained in special tanks of ships to improve stability. It often contains organisms that are non-native to waters in which it is discharged, which can lead to introductions of alien species.

Bedrock:  Substrate type consisting of unbroken rock strata.

Benthic:  Species that generally inhabits waters near or on the bottom substrate, infrequently swimming above it.

Benthopelagic:  Species that generally inhabits bottom waters and open midwaters or near the surface.

Bog:  A waterlogged, peat-forming area, dominated by Sphagnum mosses and poor in nutrients, often with brown stained water.

Boulder:  Substrate type consisting of large stones, greater than 256 mm.

Brackish:  Saline water whose salinity is not as high as in the sea; having a salt concentration between that of freshwater and seawater (usually 0.5-30 parts per thousand salt). Typical of marine estuaries.

°C:  Degrees Celsius.

Carnivore:  Species that eats fish (piscivore) and/or other vertebrates. Includes parasitic feeders.

Catadromous:  Species that spends most of its life span and grows to sexual maturity in freshwater but migrates to a marine (saltwater) environment to spawn.

Clay:  Substrate type consisting of fine inorganic material <0.004 mm in diameter; may be compacted.

cm:  Centimetre.

Coarse Fish:  Species considered as being of inferior quality or value. Most may be legally taken using non-angling methods.

Cobble:  Substrate type consisting of small to medium stones 64 to 256 mm in diameter, larger than gravel and smaller than boulder.

Coldwater:  Species that is best adapted, prefers or usually occurs at water temperatures less than 19°C, during summer months.

Commercial Fishery:  The harvesting and marketing of fish for sale.

Common:  Species frequently encountered, usually with a widespread range.

Confluence:  The place where two streams join to form a single larger stream.

Coolwater:  Species that is best adapted, prefers or usually occurs at water temperatures between 19 and 25°C, during summer months. Preferred temperatures may also include coldwater or warmwater ranges.

COSEWIC Status:  Species designation assigned by the Committee on the Status of Endangered Wildlife in Canada.

Extinct (X): A wildlife species that no longer exists.

Extirpated (XT): A wildlife species that no longer exists in the wild in Canada, but exists elsewhere.

Endangered (E): A wildlife species facing imminent extirpation or extinction.

Threatened (T): A wildlife species that is likely to become an endangered if nothing is done to reverse the factors leading to its extirpation or extinction.

Special Concern (SC): A wildlife species that may become threatened or endangered because of a combination of biological characteristics and identified threats.

Data Deficient (DD): A category that applies when the available information is insufficient (a) to resolve a wildlife species' eligibility for assessment or (b) to permit an assessment of the wildlife species' risk of extinction.

Not at Risk (NAR): A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Creek:  A natural small to medium lotic waterway.

Detritivore:  Species that consumes detritus.

Detritus:  Substrate type consisting of nonliving organic matter in various states of decomposition.

Dissolved Oxygen:  The oxygen concentration occurring in water, measured in mg/L or percent saturation.

Diurnal:  Mainly active during the day.

Economic Importance:  Considered value of a species for commercial, recreational or other uses.

Embayment:  Indentation in a shoreline forming a bay.

Endemic:  Native species that is restricted in its global range to the Great Lakes or Ontario.

Epilimnion:  The warmer upper layer of water in a stratified lake, extending from the surface to the thermocline.

Estuarine:  Marine environment that is influenced by freshwater dilution. Occurs where a river discharges to saltwater.

Euryhaline:  Tolerant of a wide range of salinities.

Eutrophic:  Nutrient rich body of water having a high rate of biological production.

(f):  Female.

Fall:  Season characterized by decreasing water temperature and photoperiod, usually September to November.

Fecundity:  The yearly reproductive potential of a female based on the number of mature ova (eggs) produced. Fecundity usually changes with the age and size of the fish.

FL (Fork Length):  The measured straight-line distance from the most forward point of the head to the middle of the fork in the caudal fin.

Forage Fish:  Species that is important as a food source for other species.

Fractional Spawner:  Species that spawns many times over a protracted spawning season. Ovaries contain eggs at various stages of development.

General Abundance:  The relative likelihood or frequency of occurrence of a species assuming suitable habitat conditions.

Gradient:  The general slope, or rate of change in vertical elevation per unit of horizontal distance, of the water surface in a flowing stream.

GRank (Global Rank):  Global conservation status ranks are assigned by NatureServe scientists with input from relevant natural heritage member programs and experts on particular taxonomic groups. These ranks reflect an assessment of the condition of the species across its entire range.

GX: Presumed Extinct; not located despite intensive searches and virtually no likelihood of rediscovery.

GH: Possibly Extinct; missing; known from only historical occurrences but still some hope of rediscovery.

G1: Critically Imperiled; at very high risk of extinction due to extreme rarity (often 5 or fewer populations), very steep declines, or other factors.

G2: Imperiled; at high risk of extinction due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors.

G3: Vulnerable; at moderate risk of extinction due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors.

G4: Apparently Secure; uncommon but not rare; some cause for long-term concern due to declines or other factors.

G5: Secure; common, widespread, and abundant.

G#G#: Range Rank; a numeric range rank is used to indicate the range of uncertainty in the status of a species.

GU: Unrankable; currently unrankable due to lack of information or due to substantially conflicting information about status or trends.

GNR: Unranked; global rank not yet assessed.

GNA: Not Applicable; a conservation status rank is not applicable because the species is not a suitable target for conservation activities (i.e., hybrid).

?: Inexact Numeric Rank; denotes inexact numeric rank (e.g., G2?).

Q: Questionable Taxonomy; taxonomic distinctiveness of this entity at the current level is questionable; resolution of this uncertainty may result in change from a species to a subspecies or hybrid, or the inclusion of this taxon in another taxon, with the resulting taxon having a lower-priority conservation priority.

C: Captive Only; at present extant only in captivity, or as a reintroduced population not yet established.

T#: Infraspecific Taxon; the status of infraspecific taxa (subspecies or varieties) are indicated by a "T-rank" following the species' global rank.

Gravel:  Substrate type consisting of pebbles and small stones, 2 to 64 mm in diameter, larger than sand and smaller than cobble.

Groundwater:  Water that flows below the ground, in contrast to surface water, which flows above the ground.

Habitat:  The place where an organism lives and its surroundings, including physical, chemical and biological features.

Herbivore:  Species that is a primary consumer eating green plant biomass made by photosynthesis. Green plants include phytoplankton, epilithic algae, epiphytic algae and macrophytes.

Hybrid:  The progeny of crossbreeding among species.

Hypolimnion:  The colder lower layer of water in a stratified lake, extending from the bottom to the thermocline.

Impoundment:  A lentic body of water created by a dam, i.e., reservoir.

Indigenous:  Native to a given area.

Intermediate:  Species that is neither particularly sensitive nor insensitive to environmental or anthropogenic stresses.

Intermittent:  A stream that flows only at certain times of the year.

Intolerant:  Species that is sensitive to environmental or anthropogenic stresses.

Introduced:  Species that was not native to Ontario waters or portions thereof prior to arrival of Europeans.

Invasive Species:  Introduced species that threatens the diversity or abundance of native fish species.

Invertivore: Species that feeds on invertebrates including insects, molluscs and crustaceans.

Juvenile:  Young fish that has not reached sexual maturity.

kg:  Kilogram.

Lacustrine:  Freshwater environment referring to lakes and aspects of lakes, consisting primarily of lentic (standing water) habitats.

Lake:  A natural medium to large lentic waterbody.

Length Basis:  The length measurement on which length-weight regression coefficients were calculated (i.e. total [TL], fork [FL] or standard [SL]).

Length-weight Regression Coefficients:  Parameters of intercept (a) and slope (b), used to describe the relationship between length (L) and weight (W) in the equation log₁₀W (g) = a+b•log₁₀L (mm).

Lentic:  An aquatic system with standing waters such as a pond or lake.

Lifespan:  Normal to maximum life expectancy.

Limited Distribution:  Species that may be commonly or uncommonly encountered, but has a small range.

Lotic:  An aquatic system with flowing waters such as a brook, stream, creek or river.

(m):  Male.

m:  Metre.

Macrophyte:  Large rooted aquatic plant.

Marine:  Saltwater environment consisting of oceans and seas and their associated aspects.

Max:  Maximum.

Meandering:  A stream having a pattern of successive meanders.

mg/L:  Milligrams per litre.

Migration:  Directed movement, often cyclic, for the purpose of spawning, feeding or other factors.

mm:  Millimetre.

Mud:  A substrate type comprised of a mixture of clay and silt.

Native:  Indigenous, naturally occurring species that was present prior to the arrival of Europeans.

Native/Introduced:  Species that is indigenous to Ontario, but has been introduced to non-native ecosystems outside its native range.

Natural Dispersal:  Species that has expanded its range into Ontario through natural means.

Natural Hybrid:  The progeny of crossbreeding between species that is known to occur in nature.

Naturalized:  A self-sustaining population of an introduced species.

Nonindigenous:  Not native to a given area.

NRank (National Rank):  National conservation status ranks in Canada are assigned similar to global ranks. The condition of a species can vary from one country to another, and national conservation status ranks document its condition in a particular country.

NX: Presumed Extirpated; species is believed to be extirpated from the nation. Not located despite intensive searches of historical sites and other appropriate habitat, and virtually no likelihood that it will be rediscovered.

NH: Possibly Extirpated; species occurred historically in the nation, and there is some possibility that it may be rediscovered. Its presence may not have been verified in the past 20-40 years

N1: Critically Imperiled; critically imperiled in the nation because of extreme rarity (often 5 or fewer occurrences) or because of some factor(s) such as very steep declines making it especially vulnerable to extirpation.

N2: Imperiled; imperiled in the nation because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation.

N3: Vulnerable; vulnerable in the nation due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors making it vulnerable to extirpation.

N4: Apparently Secure; uncommon but not rare; some cause for long-term concern due to declines or other factors.

N5: Secure; common, widespread and abundant in the nation.

NNR: Unranked; national conservation status not yet assessed.

NU: Unrankable; currently unrankable due to lack of information or due to substantially conflicting information about status or trends.

NNA: Not Applicable; a conservation status rank is not applicable because the species is not a suitable target for conservation activities (i.e., exotic or hybrid).

N#N#: Range Rank; a numeric rank is used to indicate the range of uncertainty about the status of the species.

N#B: Breeding; for a migratory species, applies to the breeding population.

N#N: Non-breeding; for a migratory species, applies to the non-breeding population.

N#M: Migratory; for a migratory species, rank applies to the transient (migrant) population.

?: Inexact or Uncertain; denotes inexact or uncertain numeric rank.

Nursery Habitat:  Area that provides the necessities for the rearing of juvenile fish.

Oligotrophic:  Nutrient poor waterbody, characterized by coarse substrates, sparse aquatic vegetation and low production of plankton and fish.

Oxbow:  The looped end of the meander that has become isolated from the main branch of a river due to erosion, which resulted in a by-pass of flow.

Pan Fish:  Small fish species easily captured by angling, often found in large numbers, which is harvested for fun or food.  Includes many members of the sunfish family. Harvest limits are usually generous or unlimited.

Parasitic:  Species that attaches to the body of another species to derive nourishment, but usually does not kill it

Pelagic:  Species that inhabits the open waters, in contrast to bottom-living (benthic) or inshore species.

Perennial:  A stream that flows continuously throughout the year.

Periphyton:  Small plant-like organisms, typically algae, growing on a substrate.

pH:  A measure of the hydrogen-ion activity in a solution, expressed as the negative log₁₀ of hydrogen ion concentration on a scale of 0 (highly acidic) to 14 (highly basic) with a pH of 7 being neutral.

Planktivore:  Species that feeds by filtering plankton from the water column.

Plankton:  Tiny plants (e.g. algae (phytoplankton)) and animals (e.g. protozoa, small crustaceans (zooplankton)) that live in aquatic ecosystems and are moved about by water currents and wave action.

Pond:  A small lentic waterbody.

Pool:  Stream habitat type characterized by a smooth undisturbed surface, generally slow current, and some moderate ore deep water for the size of the stream.

Range:  The geographic area occupied by a species.

Rare:  Species that is very infrequently encountered, usually due to limited suitable habitat and/or a very small range.

Reproductive Guild:  A group with similar strategies to raise their young (i.e., parental care).

A.1.1: Nonguarders: Open substratum spawners: Pelagophils - Large quantities of non-adhesive, near-neutral or buoyant eggs are scattered in open water. No parental care of eggs.

A.1.2: Nonguarders: Open substratum spawners: Litho-pelagophils - Eggs are deposited on rocks and gravel, but eggs, embryos or larvae become sufficiently buoyant to be carried away from the spawning substrate by water currents. No parental care of eggs.

A.1.4: Nonguarders: Open substratum spawners: Phyto-lithophils - Deposit eggs in relatively clearwater habitats on submerged plants, if available, or on other submerged items such as rocks, logs or gravel, where their embryos and larvae develop. No parental care of eggs.

A.1.5: Nonguarders: Open substratum spawners: Phytophils - Scatter or deposit eggs with an adhesive membrane that sticks to submerged, alive or dead, aquatic plants or to recently flooded terrestrial vegetation.  Sometimes logs and branches. No parental care of eggs.

A.1.6: Nonguarders: Open substratum spawners: Psammophils - Usually small eggs with an adhesive membrane that are scattered directly on sand and/or the fine roots of plants that hang over the sandy bottom. No parental care of eggs.

A.2.3: Nonguarders: Brood hiders: Lithophils - Eggs are hidden in specially constructed places.  In most cases the hiding places (called redds in salmonids) are excavated in gravel by the female. No parental care of eggs.

A.2.4: Nonguarders: Brood hiders: Speleophils - Usually few large eggs with an adhesive membrane that are hidden in crevices. No parental care of eggs.

B.1.3: Guarders: Substratum choosers: Lithophils - Choose rocks for attachment of their eggs. Eggs are guarded, and possibly cleaned and ventilated.

B.1.4: Guarders: Substratum choosers: Phytophils - Choose plants for attachment of their eggs. Eggs are guarded, and possibly cleaned and ventilated.

B.2.2: Guarders: Nest spawners: Polyphils - No particular nest building material or substrate is chosen, however, a nest is constructed and the nest and eggs are guarded.

B.2.3: Guarders: Nest spawners: Lithophils - Eggs are deposited on cleaned areas of rocks or in pits dug in gravel. Nest is guarded.

B.2.4: Guarders: Nest spawners: Ariadnophils - The nest building male has the ability to spin a viscid thread from a kidney secretion, which binds the nest of different material together. The eggs are guarded and ventilated by the male, who also guards the young once they hatch.

B.2.5: Guarders: Nest spawners: Phytophils - Eggs are deposited in nests constructed above or on a soft muddy bottom, often amid algae or other exposed roots of vascular plants. Nest is guarded.

B.2.7: Guarders: Nest spawners: Speleophils - These fishes guard a clutch of eggs in natural holes or cavities, in specially constructed burrows, or where deposited on a cleaned area of the undersurface of flat stones.

Reservoir:  An artificial water body, usually created by the damming of a river.

Riffle:  Stream habitat type characterized by a broken or choppy surface, moderate or fast current, and relatively shallow depth.

Riparian Vegetation:  Vegetation along the edge of a body of water.

River:  A natural medium to large lotic waterway.

Riverine:  Freshwater environment referring to rivers, including streams and creeks, and their associated aspects consisting primarily of lotic habitats (flowing water).

Run:  Stream habitat type intermediate between pool and riffle, characterized by a smooth often roiled surface, moderate to swift current and shallow to moderate depth.

Salinity:  The salt concentration of water, measured in parts per thousand.

Sand:  Substrate type consisting of inorganic fragments between 0.062 and 2 mm in diameter. Particles are smaller than gravel and larger than silt.

SARO Status:  Classification assigned to native Ontario species by the Committee on the Status of Species at Risk in Ontario (COSSARO).

Extinct (EXT): A species no longer lives anywhere in the world.

Extirpated (EXP): A species lives somewhere in the world, lived at one time in the wild in Ontario, but no longer lives in the wild in Ontario.

Endangered (END): A species lives in the wild in Ontario but is facing imminent extinction or extirpation.

Threatened (THR): A species lives in the wild in Ontario, is not endangered, but is likely to become endangered if steps are not taken to address factors threatening it.

Special Concern (SC): A species lives in the wild in Ontario, is not endangered or threatened, but may become threatened or endangered because of a combination of biological characteristics and identified threats.

Not at Risk (NAR): A species that has been evaluated and found to be not at risk.

Data Deficient (DD): A species for which there is insufficient information for a provincial status recommendation.

Semelparous:  Organism which reproduces only once in its lifetime. Often dies shortly thereafter.

Shoal:  A submerged ridge, bank, or bar consisting of, or covered by, unconsolidated sediments (mud, sand, gravel, cobble, boulder) which rises above the bottom.

Silt:  Substrate type consisting of minute particles 0.004 to 0.062 mm in diameter, smaller than sand and larger than clay.

Siltation:  The accumulation of fine water-borne sediments over coarser substrate.

SL (Standard Length):  The measured straight-line distance from the most forward point of the head to the hidden base of the tail, as indicated by the crease formed when the tail is bent to one side.

Spawning Habitat:  Area that provides the necessities for activities associated with reproduction.

Spawning Season:  Time of year when a species usually undertakes reproductive activities.

Species:  Group of organisms of common ancestry that normally are able to reproduce only among themselves and that are usually geographically distinct.

Species Code:  Number assigned to a species by the Ontario Ministry of Natural Resources.

Sport Fish:  Species that are harvested for personal use, recreation, or challenge. Harvest of these species is usually regulated.

Spring:  Season characterized by increasing water temperature and photoperiod, usually March to May.

SRank (Subnational Rank):  Subnational conservation status ranks are assigned for Ontario by the Natural Heritage Information Centre (NHIC) to set protection priorities for rare species.

SX: Presumed Extirpated; species is believed to be extirpated from the province. Not located despite intensive searches of historical sites and other appropriate habitat, and virtually no likelihood that it will be rediscovered.

SH: Possibly Extirpated; species occurred historically in the province, and there is some possibility that it may be rediscovered. Its presence may not have been verified in the past 20-40 years.

S1: Critically Imperiled; critically imperiled in the province because of extreme rarity (often 5 or fewer occurrences) or because of some factor(s) such as very steep declines making it especially vulnerable to extirpation.

S2: Imperiled; imperiled in the province because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation.

S3: Vulnerable; vulnerable in the province due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors making it vulnerable to extirpation.

S4: Apparently Secure; uncommon but not rare; some cause for long-term concern due to declines or other factors.

S5: Secure; common, widespread and abundant in the province.

SNR: Unranked; provincial conservation status not yet assessed.

SU: Unrankable; currently unrankable due to lack of information or due to substantially conflicting information about status or trends.

SNA: Not Applicable; a conservation status rank is not applicable because the species is not a suitable target for conservation activities (i.e., exotic or hybrid).

S#S#: Range Rank; a numeric rank is used to indicate the range of uncertainty about the status of the species.

?: Inexact or Uncertain; denotes inexact or uncertain numeric rank.

Stagnant:  Motionless water, not flowing in a stream or current.  Also known as standing water.

Stock:  A separate breeding population of a species.

Stream:  Natural watercourse containing flowing water, such as a creek or river.

Stream Resident:  Fish of an anadromous species that remain in a riverine environment throughout their life cycle.

Submergent:  Rooted plants completely or mostly growing below the surface of the water.

Substrate:    Materials that comprise the bottom.

Summer:  Season characterized by the warmest water temperature and longest photoperiod, usually June to August.

Taxonomic Authority:  Author credited with providing the first account of a species.

Temp:  Temperature.

Thermal Regime:  Preferred temperature range of a species.

Thermocline:  The thin transition layer of water between the warmer epilimnion above and the colder hypolimnion below.

TL (Total Length):  The measured straight-line distance from the most forward point of the head to the end of the tail fin, with the lobes of the tail fin compressed.

Tolerance:  Ability of a species to adapt to environmental perturbations or anthropogenic stresses.

Tolerant:  Species that is fairly insensitive or adaptive to environmental or anthropogenic stresses.

Tributary:  A stream feeding, joining, or flowing into a larger stream, lake or ocean.

Trophic Class:  The position in the food chain or web that a species occupies.

TSN (Taxonomic Serial Number):  A unique identification number assigned by Integrated Taxonomic Information System (ITIS) of North America. This unique identifier is a permanent identification for that taxonomic entry.

Turbidity:  Water clouded by suspended inorganic particles, usually clay or silt.

Uncommon:  Species occasionally encountered, may have a somewhat restricted range.

Warmwater:  Species that is best adapted, prefers or usually occurs at water temperatures greater than 25°C, during summer months.

Waterbody:  A homogenous classification that can be assigned to rivers, lakes, estuaries, oceans, or other water features.

Wetland:  A permanently or seasonally waterlogged area, such as a marsh, swamp, bog or fen.

Winter:  Season characterized by the coldest water temperature and shortest photoperiod, usually December to February.

Yrs:  Years.

Last update:  14 March 2023