Status of Sauger in Montana

Abstract

Though abundant throughout the Yellowstone and Missouri River drainages in eastern Montana prior to the 1990s, recent survey data suggest that native sauger (Stizostedion canadense) have declined throughout the state. We compared historical and recent survey information to assess the extent of the decline, examine possible reasons for the decline, and suggest management options for protecting and bolstering remaining populations. Sauger declined state-wide in concert with the drought in the late 1980s in several locations including the Missouri River, Fort Peck Reservoir, and Yellowstone River. Despite improved flows since the mid-1990s, there was little rebound in sauger numbers in most locales. Of special concern are the substantial declines in spawning runs of sauger in several key spawning tributaries (Marias, Milk, and Tongue rivers). Estimated range of sauger in 1999 was 1570 km, a 53 percent decline from their historical range. Decline of this highly migratory species was more extensive in tributaries (75%) because of loss of migration routes caused by damming and dewatering. The roles of hybridization with walleye (Stizostedion vitreum vitreum), interactions with abundant nonnative piscivores (walleye and smallmouth bass Micropterus dolomieu), and angler harvest in the sauger decline are uncertain. Better information is needed on movement patterns, spawning ecology, fish passage problems, and angler harvest to develop management actions for sauger recovery.