Smallmouth Bassin’ in Ririe Reservoir

When some anglers think of Ririe Reservoir they may picture limits of silvery kokanee or Yellow Perch fish fries, but there’s another fishy critter that can provide hours of entertainment at the end of your line, Smallmouth Bass Micropterus dolomieu. Not only are Smallmouth Bass abundant and fun to catch in Ririe Reservoir they are also excellent table fare. Smallmouth Bass are members of a family of fishes known as Centrarchids, which also includes Bluegill and other freshwater sunfish, none of which are native to Idaho. The Idaho Department of Fish and Game (IDFG) introduced Smallmouth Bass into Ririe Reservoir in 1984-1986 to diversify fishing opportunities in the Upper Snake Region. However, due to the short growing season in Ririe they don’t achieve trophy size like Smallmouth Bass in more productive areas. Limited bass growth potential at Ririe Reservoir is identified as a limiting factor in the IDFG Fishery Management Plan which directs the department to continue to manage for a satisfactory Smallmouth Bass fishery.        

During mid-July this summer, we conducted night electrofishing at 24 sites along the shoreline of Ririe Reservoir. Prior to 2008, we sampled a fewer number of sites along the shoreline. We have been monitoring Smallmouth Bass at these sites about once every five years since 2008 and we estimate the relative abundance of bass by the metric of catch-per-unit-effort (CPUE), or the number of bass caught per hour of electrofishing (Figure 1).

We saw an increase in the abundance of Smallmouth Bass in our survey this year compared to other years, and we also recorded an increase in fish length from 5 inches in 2018 to 6 inches in 2023 with Smallmouth Bass up to 11 inches being sampled. Despite sampling bass on the smaller side with our electrofishing gear, anglers that fish Ririe often catch bass in the 14–16-inch range.

     Ririe Reservoir isn’t the only fishery where anglers can target Smallmouth Bass, they are also found in the summer months migrating into Willow Creek upstream of the reservoir. A recent survey conducted in Willow Creek found average catch rates of Smallmouth Bass by anglers at 11 fish per hour with an average length of 7 inches. With the close proximity of both Ririe Reservoir and Willow Creek to Idaho Falls, local anglers have the opportunity to catch an aggressive and tasteful fish that will keep the fishing hot.