Relation of Age-0 Largemouth Bass Abundance to Hydrilla Coverage and Water Level at Lochloosa and Orange Lakes, Florida

Abstract

Changes in electrofishing catch per hour (CPH) of age-0 largemouth bass Micropterus salmoides were examined in relation to aquatic macrophytes and seasonal water elevation at Lochloosa and Orange lakes, Florida, during the 1990s. At Lochloosa Lake, stepwise multiple regression revealed a significant positive relationship between the mean CPH of age-0 largemouth bass and the percentage of areal coverage by hydrilla Hydrilla verticallata. At Orange Lake, mean CPH was directly associated with the percentage of areal coverage by hydrilla and inversely related to summer water levels. Thus, the influence of vegetation on age-0 largemouth bass abundance was similar at both lakes, but the effects of water levels were not. Further investigations into the effects of fluctuations in water levels on age-0 large-mouth bass in natural lakes are needed. Aquatic macrophytes are important to lake function at multiple scales, and relationships between fish numbers and macrophyte levels are an important consideration in fisheries management. Vegetation influences water chemistry (Boyd 1971; Canfield et al. 1985) and aids in sediment stabilization (McGsha 1952) in lakes. Increased