Comparison of Walleye Habitat Suitability Index (HSI) information with habitat features of a Walleye spawning stream

Abstract

We compared habitat conditions in a stream where Walleye successfully produce fry and compared them to a nationally applicable Habitat Suitability Index (HSI) model for Walleye. During a 2-3-week migration period in each of 3 years, Walleye were observed spawning; eggs were collected primarily in April and fry in May each year. Water depths, velocities and temperatures were at the lower end of or below the optimum ranges described in the HSI for spawning Walleye; however, random sampling indicated that optimum conditions for these parameters generally did not exist in the stream. Substrate, dissolved oxygen, and pH in the stream were optimal according to the HSI. Our results indicate that predictions using the HSI alone are not sufficient to identify regional streams where Walleye might successfully establish viable populations.