A probabilistic analysis of decision-making about trip duration by Strait of Georgia sport anglers

Since 1984, an access-point creel survey of the Strait of Georgia, British Columbia, sport fishery has generated data on catch, effort, and attributes of effort from thousands of interviews of salmon anglers completing a daily boat-trip. I present a maximum-likelihood model for this daily bag limit (DBL) constrained fishery that estimates catch rate and variance for various angling fleets (as defined by boat-trip attributes such as the number of angling lines), estimates the probability that a boat-trip ends after a certain number of hours angling, and measures how angling success influences that probability. Most anglers targeting either chinook salmon ( Oncorhynchus tshawytscha ) or coho salmon (Oncorhynchus kisutch) became more likely to end a boat-trip in response to angling success, i.e., they were satiated by angling success before reaching a DBL. However, autumn and winter chinook salmon anglers tended to extend a boat-trip in response to angling success, i.e., they were motivated by angling success. Variability in angling success could not be attributed to variability in angler skill. Coho salmon catch rates increased by about 42% with each additional angling line per boat-trip up to three. The model can be used to judge the effectiveness of a DBL in reducing daily catch. Resume : Depuis 1984, une enquete menee aux points d'acces aupres des pecheurs sportifs dans le detroit de Georgie (Colombie-Britannique), a fourni des donnees sur les prises, l'effort de peche et les attributs de ce dernier. Des milliers d'entrevues de pecheurs sportifs de saumon effectuant des sorties en bateau d'une journee ont ete realisees. Je presente un modele fonde sur le maximum de vraisemblance pour cette peche restreinte par des limites quotidiennes de prises, modele qui estime le taux de capture et la variance des captures pour diverses flottilles (definies selon les attributs des sorties, comme le nombre de lignes) et la probabilite qu'une sortie se termine apres un certain nombre d'heures de peche, et qui mesure comment le succes de la peche influe sur cette probabilite. Chez la plupart des pecheurs de