Fish Community Changes in Lake Spokane (Long Lake), Washington, from 2001 to 2024

The Washington Department of Fish and Wildlife conducted three standardized surveys in 2001, 2015 and 2024 to track changes in the fish community of Lake Spokane (Long Lake) over the 23-year period. Over the course of the study, the relative abundance of all native species decreased 53% in total number and 23% in total biomass from 2001 to 2024. Conversely, the relative abundance of nonnative species increased 55% in total number and 74% in total biomass over the same period. The results of this study document large increases in two predator species, Smallmouth Bass and Walleye. The Smallmouth Bass population increased more than 2-fold during the first period of this study (2001-2015), which coincided with declines of Largescale Sucker, Largemouth Bass and Black Crappie. During the second period of this study (2015-2024), the Walleye population increased more than 9-fold and their proportional size distribution values increased in all size categories. The rapid and significant increase in the Walleye population corresponded to decreases in both native and nonnative species during the 2015-2024 time period. It appears the Smallmouth Bass population in Lake Spokane has matured and remains relatively constant, while the Walleye population continues to grow in both quantity and quality, and may be approaching maturity. There has been a succession of top predator species in Lake Spokane, where Smallmouth Bass and Walleye appear to be responsible for the reduction of the native species community and several nonnative species, in the process of biotic homogenization.