Consumption of Native Juvenile Salmonids by Northern Pike in the Upper Flathead River System

Findings:

• Population estimates of northern pike in the lower Flathead River ranged from 1,200 to 1,300 individuals.

• Westslope cutthroat trout were found in the diet of younger and older pike during all seasons. Bull trout were found only in larger pike during all seasons except summer.

• Northern pike consume a total of 8.0 metric tons of fish (342,000 fish) annually. 0.8 metric tons of bull trout (3,500 fish) are consumed and 0.4 metric tons of westslope cutthroat trout (13,000 fish) each year.

• Results suggest that predation by introduced northern pike is contributing to the lower abundance of native salmonids in the system and that a possible benefit might accrue to native salmonids by reducing these predatory interactions.

For more information see: Muhlfeld, C.C., David Bennett, R. Kirk Steinhorst, Brian Marotz and Matthew Boyer 2008. Using Bioenergetics Modeling to Estimate Consumption of Native Juvenile Salmonids by Nonnative Norther Pike in the Upper Flathead River System, Montana. North American Journal of Fisheries Management.