Objectives

• 1) Does the use of habitat augmentation structures by largemouth bass differ seasonally in a large reservoir?
• 2) Does the use of habitat augmentation structures by largemouth bass differ through the different daily time periods (day, night) in a large reservoir?

Overview

Deteriorating reservoir fish habitat is a concern throughout the US so the Missouri Department of Conservation and cooperators placed approximately 1,600 structures (trees, stumps, and rock piles) throughout Table Rock Lake, Missouri to improve fish habitat for largemouth bass Micropterus salmoides and other species. Our objective was to determine movement and habitat selection of largemouth bass and to determine if these fish select for the augmentation structures within the lake. Sixty largemouth bass (>380 mm total length) were implanted with radio transmitters in April 2011 and relocated monthly since May 2011. Discrete choice analysis results indicate that largemouth bass selected for cover (boat docks, rock ledges, and coarse woody debris) compared to open water, but submerged trees were the only augmentation structure selected. Movement rates of up to 20 fish per month that were relocated  every 3-4 hours for one, 24-hour period per month were greatest during summer (mean=53 m/h) and lowest during fall (mean=16 m/h) and winter (mean=19 m/h) and were 2-3 times greater during the day than night. Largemouth bass may select for structure, but not necessarily all types, and that increased summer movement may mean fish may use more reservoir habitat in summer.