Ed Baum’s book Maine Atlantic Salmon: A National Treasure
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.
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.