Comparison of Walleye Habitat Suitability Index (HSI) Information with Habitat Features of a Walleye Spawning Stream

Abstract

The objective of our study was to determine habitat conditions in a stream where walleye successfully produce fry and to compare these conditions with the nationally-applicable Habitat Suitability Index (HSI) model for walleye. During 17–20 d migration periods in April of 1996, 1997 and 2000, walleye were observed spawning; eggs were collected primarily in April and fry primarily in May. Water depths, velocities, and temperatures where walleyes spawned were at the lower end of or below the optimum ranges specified in the HSI for spawning walleye. However, random sampling indicated that optimum HSI conditions for these parameters generally did not exist in the stream. Substrate, dissolved oxygen, and pH were optimal according to the HSI. Our results indicate that predictions using the HSI alone are not sufficient to identify regional tributaries where walleye can successfully establish viable populations.