Relation Between Sport-Fishing Catchability Coefficients and Salmon Abundance

Abstract

Pacific salmon sport-fishing data without time trends in the catchability coefficient q or in fish abundance N show that q is larger at lower N. This phenomenon causes serious management problems because it creates critical thresholds in population size and fishing effort that can lead to stock extinction. The inverse relation between q and N directly parallels the analogous relation shown by some predators in natural ecosystems.