Fecundity of Atlantic Salmon (Salmo salar) from Two Maine Rivers

Abstract

Estimates of numbers of eggs in 164 hatchery-spawned Atlantic salmon (Salmo salar) from two Maine rivers ranged from 3528 to 18,847, and egg number per pound of total body weight from 523 to 1385. Sample autopsies of 10 salmon revealed that artificial spawning removed an average of more than 97% of the eggs in the body cavity. There was no significant difference between von Bayer and displacement estimates of fecundity. Valid estimates of the potential egg deposition of Atlantic salmon runs in the two Maine rivers studied can be made using routinely collected trapping data and the regression formulae based on fish length resulting from this study. Salmon that spent 2 years at sea before spawning contained lower total numbers of eggs but appeared to have a higher rate of fecundity than older fish. Factors governing egg size could not be isolated. Loss in body weight during spawning is discussed.