The maximum sustainable yield management of an age-structured salmon population: Fishing vs. conservation

This paper develops a sustainable yield harvesting model for the wild Atlantic salmon (Salmo salar), where the population comprises different age classes. It is shown that the weight– fecundity relationship of the spawning population, comprising young and old fish, is crucial for the maximum sustainable yield fishing composition. First, the optimal harvest is found when fecundity is approximated by weight. Second, we analyze what happens when weight is an inaccurate approximation for fertility. Finally, the conservation perspective is taken into account when the maximum sustainable yield is maximized subject to a minimum viable size of the harvestable, or spawning, population. It is shown that the conservation perspective does not affect the qualitative structure of the optimal harvest policy in which the old mature fish are more aggressively targeted than the young mature population.