Regional Evaluation of the Relation of Habitat to Distribution and Abundance of Smallmouth Bass and Largemouth Bass in Missouri Streams

Abstract Fish-habitat models for streams were developed to help explain the decline and possible replacement of smallmouth bass Micropterus dolomieu by largemouth bass M. salmoides in the Ozark Border region of Missouri. We identified habitat conditions associated with the distribution and abundance of both species in sympatric and allopatric situations by means of correlation analysis and multiple linear regression models. Maximum summer temperature and percent pool area explained most of the variability in total densities, adjusted densities (fish larger than 100 mm total length), and biomass for both species. Smallmouth bass were negatively associated with each variable, whereas largemouth bass were positively associated. Physical habitat that is usable as cover was not associated with the abundance of either species. Final models explained about 50% of the variation in the population characteristics of both species and showed good accuracy and precision across years. Adjusted-density models appeared t...