By Joe Thiessen, Regional Fisheries Biologist
Spring Valley Reservoir is a popular fishery for warmwater fish as well as stocked trout, and it is located approximately 20 miles east of Moscow, Idaho. In recent years, we have seen a decrease in the size of many fish species, especially Largemouth Bass. Upon investigation, we documented high amounts of harvest on Largemouth Bass and limited amounts of protective cover for all warmwater fish. Despite a change in regulations to limit harvest of bass, improvements in their size and abundance have not occurred.
To increase the size and number of bass and other warmwater species in Spring Valley Reservoir, we felled 32 large trees into the reservoir over the last two years. Our goals are to create sanctuaries for bass to escape heavy fishing pressure from anglers, improve rearing habitat for panfish, and increase ambush cover for adult predator fish such as bass. Over the next couple of years, IDFG will evaluate these structures to see if they are accomplishing our objective of increasing the abundance of larger Largemouth Bass and panfish and making fishing better for anglers.