Regional Factors Affecting Smallmouth Bass and Largemouth Bass Recruitment in Midwestern USA Reservoirs

Regional factors correlated with recruitment of black bass (largemouth bass; Micropterus nigricans and smallmouth bass; Micropterus dolomieu), two important fishes, are rarely studied, despite the importance of recruitment variation in influencing fish populations. We sought to identify factors that drove variation in age-0 and age-1 black bass abundance. Age-0 or age-1 black bass catch per unit effort (CPUE) in reservoirs in Kansas and Illinois, USA, was positively correlated with local short-term (i.e., mean April precipitation) environmental variables. In contrast, age-0 or age-1 black bass CPUE was generally negatively correlated with long-term environmental variables and river regulation metrics (i.e., reservoir elevation) in the Mississippi and Missouri river reservoirs. Our findings highlight that consideration of spatiotemporal scale is important when managing black bass populations.