A

A-run steelhead
Summer steelhead crossing Bonneville Dam on or before August 25.

Abdomen
Belly or lower area of a fish, especially between the pelvic fins and anus.

Abdominal pelvics
Pelvic fins located on the abdomen far behind the pectoral fins; pelvic bones do not attach to pectoral girdle.

Absolute Recruitment
The number of fish which grow into the catchable size range in a unit of time (usually a year).

Abundance Index
Information obtained from samples or observations and used as a measure of the weight or number of fish which make up a stock.

Accessory pelvic appendage
A tapered fleshy lobe above the base of the pelvic fin.

Acclimate
The adaptation of an organism to environmental changes.

Acclimation pond
Concrete or earthen pond or a temporary structure used for rearing and imprinting juvenile fish in the water of a particular stream before their release into that stream.

Action of a lure:
The specific movement of a lure through the water

Action of a rod:
Its dynamic response to load and force, described as stiff action, parabolic action, etc.

Adaptation
Changes in an organism's structure or habits that allow it to adjust to its surroundings.

Adfluvial
Possessing a life history trait of migrating between lakes or rivers and streams.

Adipose fin
A small fleshy fin with no rays, located between the dorsal and caudal fins.

Adult equivalent population
The number of fish that would have returned to the mouth of the Columbia River in the absence of any prior harvest.

Aeration Tank
A chamber used to inject air into water.

Aerator
A portable, battery-operated air-pump for oxygenating the water in a livebait bucket. Some types plug into a car's cigarette lighter and run off the car battery.

Affluent (Stream)
A stream or river that flows into a larger one; a Tributary.

Age
The number of years of life completed, here indicated by an arabic numeral, followed by a plus sign if there is any possibility of ambiguity (age 5, age 5+)1.

Age-class
A group of individuals of a certain species that have the same age.

Air-injected deadbait
A deadbait with air injected into its body cavity with a hypodermic needle and syringe. The deadbait then fishes off the bottom.

Air-injected lobworm
A lobworm injected with air with a hypodermic needle and syringe. The lobworm fishes off the bottom.

Alevin
The developmental life stage of young salmonids and trout that are between the egg and fry stage. The alevin has not absorbed its yolk sac and has not emerged from the spawning gravels.

Alewife
A food fish belonging to the herring family.

Alkaline:
Water with a low degree of acidity

Allowance:
An amount set aside from a TAC to allow for the expected catch of fish harvesters who are not subject to quota management.

Amino acids
These are essential nutrients which the body uses to make proteins. Carp anglers use them in liquid form as an appetite stimulant in their baits.

Anadromous:
Fish that hatch rear in fresh water, migrate to the ocean (salt water) to grow and mature, and migrate back to fresh water to spawn and reproduce.

Anal fin
The fin located on the ventral median line and behind the anus.

Anchored crust
A buoyant bread crust hookbait anchored to the bottom by shot or a leger weight on the line close to the hook. It is great for chub and roach on rivers in winter.

Anchored floater rig
A rig comprising a floating hookbait on the surface, anchored in position by a leger weight on the bottom. It avoids line floating on the surface which may spook wary fish and is useful for presenting a still bait to stillwater carp and rudd.

Angling
The act of fishing with hook and line.

Aniseed
A hookbait and groundbait flavouring, in liquid or powder form, that is traditionally used to attract roach.

Annatto
An edible dye once widely used to colour homebred maggots buttery yellow, but not now commonly available.

Annual (or seasonal) Total Mortality Rate
The number of fish which die during a year (or season), divided by the initial number. Also called; actual mortality rate, *coefficient of mortality .

Annulus
A mark or ring that forms annually on the otoliths, scales, and other bones of fish, that correspond to the annual period of slow growth that fish go through. Annuli are used by fish managers to determine age and growth of fish.

Anti-eject rig
A leger rig for carp, tench or barbel that has a hookbait, usually a boilie, mounted on a hair rig in such a way that a fish cannot blow out the bait without the hook pricking its mouth.

Anti-kink vane
A small plastic strip which you mount on the line above the wire trace to prevent the line twisting and kinking when you are spinning, trolling or wobbling.

Anti-reverse
A device on a fixed-spool reel that prevents the reel backwinding and giving line when it is engaged.

Anti-tangle rig
Any kind of leger rig incorporating booms, swivels and tubing in such a way that the risk of tangling during the cast is much reduced. They are mainly used in carp fishing.

Aquatic community:
The interrelationships of biological organisms within a body of water (may also apply to Great Lakes fish)

Aquatic insects:
Water-bred insects which spend all or part of their life in water; e.g., midges, stoneflies, mayflies

Aquaculture
The controlled cultivation and harvest of aquatic plants or animals (e.g., edible marine algae, clams, oysters, and salmon).

Arlesey bomb
An aerodynamic, teardrop-shaped leger weight incorporating a small swivel, in various sizes from 3.5g (1/8oz) up.

Artificials:
Man-made baits; e.g. spoons, plugs

Assessment level
Categories of the level of complexity of and data available for each assessment included in this document; index of abundance (INDEX), yield-per-recruit analysis (YIELD), analysis of the age structure of the catch (AGE STRUCTURE), analysis including the relationship between recruitment and spawning stock size (SPAWNING STOCK) and assessment that allows prediction of future (one or two years ahead) stock sizes and catches (predictive). These levels are detailed in the subsection titled Kinds of Assessments.

Atomizer
An atomizer is useful for spraying groundbait, bloodworm and joker with a fine mist of water, to prevent them drying out. You can add flavourings to the water.

Automatic bail arm
A bail arm on a fixed-spool reel that springs open at the touch of a finger, to allow one-handed casting.

Availability
1. The fraction of a fish population which lives in regions where it is susceptible to fishing during a given fishing season . This fraction receives recruits from or becomes mingled with the non-available part of the stock at other seasons, or in other years. (Any more or less completely isolated segment of the population is best treated as a separate stock.) 2. Catch per unit of effort.

Avon rod
A through-action, 3.4-3.7m (11-12ft) rod, with a 0.45-0.7kg (1-11/2lb) test curve, for legering or float fishing for big barbel, tench, chub and bream.