ABSTRACT: From 2002 to 2011, the number of charter fishing trips in Michigan waters of Lake Huron declined by 51%. Declines in catch rates, rising gasoline prices, and the economic downturn have been suggested as possible reasons for this decline. To better understand the relative importance of these factors, five catch-based and six economic variables were evaluated using multiple regression, with charter effort from 1992 to 2011 as the response variable. Declining catch rate of introduced Chinook Salmon Oncorhynchus tshawytschawas more closely linked to declining effort than catch rate of native Lake TroutSalvelinus namaycush or Walleye Sander vitreus. The price of gasoline was a better predictor of effort than other economic variables. Although Chinook Salmon catch rate explained more variation in charter effort than any other variable, factors beyond the influence of fisheries management also influenced effort. Ecosystem changes that led to declines in salmon abundance created favorable conditions for Walleye, leading to some localized increases in charter effort.