Smallmouth Bass in the Pacific Northwest: A Threat to Native Species, a Benefit for Anglers

As a popular sportfish, smallmouth bass Micropterus dolomieu generates considerable angling opportunities with benefits to local economies even outside of their native range.  Smallmouth bass was first introduced to the Pacific Northwest (PNW) region of the United States as a sportfish over 100 years ago and is now a large component of the fish community in many streams, rivers, and lakes.  Large numbers of anglers now target smallmouth bass resulting in millions of fishing days per year, yet concurrently this species is also a primary concern due to its ecological impacts on native salmonids (Oncorhynchus spp.).  Smallmouth bass consume juvenile salmon in many areas; however, predation estimates vary widely from 0 to 3.89 salmon consumed per smallmouth bass each day across locations in PNW.  A bioenergetics model of smallmouth bass consumption suggests the interaction of water temperature and timing of salmonid outmigration influences the magnitude of smallmouth predation.  Future research needs to expand our understanding of smallmouth bass beyond a few site specific studies to inform recreational fishery management and to determine the best strategies for preventing or controlling smallmouth bass impacts on salmonids.  Lessons explored for smallmouth bass can be applied to other non-indigenous sportfish in the PNW.