Forecasting Yields of Two-Sea-Winter Atlantic Salmon ( Salmo salar ) from Icelandic Rivers

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Author: Scarnecchia, Dennis L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1984
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1139/f84-147; http://www.nrcresearchpress.com/doi/pdf/10.1139/f84-147

To forecast yields of two-sea-winter Atlantic salmon (Salmo salar) from 15 Icelandic rivers, I developed predictive regression equations based on yields of grilse of the same smolt class harvested in the previous year. The relationships were positive and significant (P < 0.05) for all rivers. The logarithm of grilse catch explained 25–85% of the variation in logarithm of two-sea-winter salmon catch the following year. Inasmuch as statistical tests for linearity between the variables were difficult to interpret and showed conflicting conclusions, I consider them inadequate for assessing whether density dependence occurs between grilse and two-sea-winter salmon. Linear or near linear relationships, which imply no density dependence, appear to occur between log grilse and log two-sea-winter salmon yields. The critical period determining run size from a given escapement thus occurs either during the freshwater rearing phase or during the first year the salmon are at sea.