Glossary

References
Ed Baum’s book Maine Atlantic Salmon: A National Treasure
http://www.maine.gov/dmr
http://www.nefsc.noaa.gov
http://www.epa.gov/region1/lab/ecology/efishing.html

Alevin:
The period after hatching of the egg when the salmon is entirely dependant upon the yolk sac for nutrition.  In the natural environment, alevin are buried within the substrate of the stream bottom.

Anadromous:
An anadromous fish, born in freshwater, spends most of its life in the sea and returns to freshwater to spawn. Salmon, smelt, shad, striped bass, and sturgeon are common examples.

Black salmon:
A synonymous term for kelt. Occasionally referred to as a slink, racer, or snake.

Bright salmon:   
A fresh-run salmon which has entered its natal stream.  Synonymous with maiden or virgin salmon.

Catadromous:   
Opposite from anadromous, catadromous fish live in freshwater and enter salt water to spawn.  American eels are a good example of a catadromous fish.

Diadromous:        
A general term for fish in the anadromous and catadromous categories.

Electrofishing:
Electro-fishing is the technique and science of utilizing an electrical current to momentarily stun fish or force them to involuntarily swim towards an electrical field for collection.

Eyed egg:
The stage from the appearance of faint eyes until hatching (April).

Fed Fry:
Atlantic salmon of hatchery origin that have fully absorbed the yolk and have begun feeding upon artificial foods.

Fingerling:   
An obsolete, non-specific term for parr that is often found in the literature prior to 1960.

Fry:
Salmon become fry when they have absorbed their yolk sac and emerge from the gravel nest the have been developing in since they were fertilised as an egg. Fry emerge in the Spring once river temperatures reach about 50F (10C) and begin feeding on invertebrates as they drift by in the stream current. (Note: this date is not appropriate for all rivers because of the wide variation in the growth and development of salmon in North America).

Green Egg:
The stage from spawning (November) until faint eyes appear in the eggs. The eggs at this stage are very fragile.

Grilse:
A 1SW salmon that has matured (or is about to mature) after one winter at sea. This term is applied to salmon in their natal river, not while at sea.

Iteroparous:
Unlike semelparous, iteroparous fish can recondition itself and return to sea to repeat the migration and spawning patterns multiple times.

Kelt:
A spawned out (spent) adult salmon (male or female) that is found in the freshwater portions of rivers, normally between November of the year of spawning until the salmon returns to the sea the following year.

Long-absence RS:
Alternate year repeat spawners that have spent one year (or more) at sea before spawning again. Long-absence repeat spawners are often referred to as LARS.

Maiden salmon:
Any virgin salmon (1SW, 2SW, 3SW) found in freshwater on its first spawning migration.

Mended-kelt:
Infrequently used term for a post-kelt that has regained the weight lost during the first spawning cycle and has resumed feeding and growth at sea.

Milt:
The male gametes (sperm).

MSW salmon:
Multi sea-winter (MSW) salmon have matured (or are about to mature) after two or more winters at sea. (Note: also see repeat spawner)

Natal Streams:   
The stream a salmon hatched in.

Otoliths:
Small bones of the inner of fish that have “growth rings” on them that can be used in aging.

Parr:
The period which follows the fry stage; subdivisions have been adopted based upon the age and size of the young salmon.

Parr marks:
0+ Parr:  The period from July 1 to December 31 of the year of hatching.  0+ Parr are less than one year old.
1 Parr:  The period from January 1 to June 30 one year after hatching.
1+ Parr:  The period from July 1 to December 31 one year after hatching.
2 Parr:  The period from January 1 to June 30 two years after hatching.
2+ Parr:  The period from July 1 to December 31 two years after hatching.
3 Parr:  The period from January 1 to June 30 three years after hatching.
3+ Parr:  The period from July 1 to December 31 three years after hatching.

Precocious Parr: 
An Atlantic salmon that becomes sexually mature in freshwater without ever going to sea.  Nearly all precocious parr are males, although a few females have been documented on rare occasions.

Post-kelt:
A spent salmon that has left the freshwater environment, until December 31 one year after spawning.

Post-smolt:
The life stage during the first year of life at sea, from July 1 to December 31 of the year the salmon left the river as a smolt.

Pre-smolt:
Parr that have commence the smoltification process in preparation for migration to sea. Another commonly used term for this stage is silvery parr.

Redd:
A gravel nest made by a spawning female. The female uses her tail to dig a pit in the stream bed where she will lay her eggs which are immediately fertilised by a male salmon. The female then covers the eggs with gravel, protecting them for the winter until they emerge in the spring as fry.

Repeat spawner (RS):
An adult salmon when found in freshwater on its second (or greater) spawning migration. Alternatively termed a previous spawner.

River Herring:
A general term used to describe the anadromous sea-run alewives and blueback herring that migrate from the ocean into the river systems April-June. These herring are the “fish that feeds all” acting as a vital food source and nutrient source at every part of its life stage. Other fish, marine mammals, and birds are just three examples of the animals that consume the river herring.

Rotary Screw Trap (RSTs):
The type of trap commonly used to evaluate the health, age distribution, and number of smolts out-migrating from the rivers in the spring (April – June). The traps consist of large cone that is turned by the river moving down through it. The fish that swim into the cone end up in a live well that sits behind the cone. The entire trap is held afloat by large aluminum pontoons on either side of the cone.

Sac-Fry:
Synonymous word for alevin; more commonly used in fish culture, where the young salmon can be observed in a hatching tray or trough.

Salmon:
Salmo salar (‘the leaper’) Atlantic salmon are an anadromous species.  Many saltwater sport­fishermen consider these fish to be “the king of fish” because of their great leaping ability and determined fight when hooked.

1SW salmon:   
A one sea-winter (SW) salmon has passed one December 31st since becoming a smolt.

2SW salmon:   
A two sea-winter (SW) salmon has passed two December 31st’s since becoming a smolt.

3SW salmon:   
A three sea-winter (SW) salmon has passed three December 31st’s since becoming a smolt.

Semelparous:   
Fish that die after spawning one time (Pacific salmon species).

Short-absence RS:
Consecutive year repeat spawners that have spent less than one year at sea before spawning again. Short-absence repeat spawners are often referred to as SARS.

Smolt:
A silvery-colored, juvenile Atlantic salmon during its active migration to sea in the spring (late April – mid June). Smolts (unlike parr) are able to survive the natural transition from fresh to salt water.

1+ Smolt:   
The birth date of Atlantic salmon is arbitrarily set at April 1.  Since smolts migrate to sea between April and June, a 1+ smolt migrates 1+ years after hatching.  In hatchery terms this is referred to as a P8, meaning after the parr was stocked in its first year of life it only spent 8 months (one fall and winter) in the river before outmigration as a smolt.

2+ Smolt:   
The period from January 1 to June 30 of the year of migration.  The migration year is two years after hatching.  In hatchery terms this is referred to as a P20, meaning the young salmon spent 20 months in the river after being stocked before outmigration.

3+ Smolt:   
The period from January 1 to June 30 of the year of migration.  The migration year is three years after hatching.  In hatchery terms this is referred to as a P32, meaning the young salmon spent 32 months in the river after being stocked before outmigration.

Smoltification:
The parr-to-smolt transformation (smoltification) results in river adaptations giving way to seawater readiness. This is where physiological changes occur in the fish to allow it to survive in saltwater environments.

Underyearling:
An obsolete, non-specific term for parr (or fingerling), often found in the literature prior to 1960.

Unfed Fry:
Atlantic salmon of hatchery origin that have fully absorbed the yolk sac and have not been fed artificial foods.

YOY:
Young of the year salmon.  Juvenile salmon found in the rivers the first summer/fall of their lives.

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