Changes in Angler Use Following an Unauthorized Walleye Introduction in Canyon Ferry Reservoir

Abstract

Angler use of Canyon Ferry Reservoir has changed following an unauthorized walleye (Sander vitreus) introduction. In summer 1986 majority ofanglers targeted rainbow trout (Oncorhynchus mykiss) (81.9%) and fished from the shoreline (62.9%). It took an average time of96 min for an angler to catch any species offish. Following expansion of the walleye population in the late 1990s, the majority of anglers in 2005 target walleye (69.2%) and fish from boats (83.2%). In 2005 it took an average of 399 min to catch any species offish. Total angler pressure has decreased from 98,768 angler days in 1989 to 80,249 angler days in 2005. Angler origin has changed little since walleye introduction with Lewis and Clark, Gallatin, and Broadwater Counties representing most anglers. Percent of out of state anglers have decreased from a peak of 10.7 percent in 1987 to a low of2.3 percent in 2004. Walleye contribute little to the winter fishery, however heavy predation of yellow perch (Percaftavesce11s) has led to declines in winter angler pressure. With declines in perch numbers, rainbow trout have become the primary component of the winter fishery. Since the introduction of walleye the Canyon Ferry fishery has become less accessible to general and shoreline anglers. Predation by walleye has reduced numbers of other sport fishes in the reservoir to the point that walleye are currently the only sport fish that meets management goals.