Elucidating the Mechanisms of Juvenile Fish Recruitment in the Middle Mississippi River

Spatial and temporal fluctuation in abundance is ubiquitous amongst animal populations. This fact is driven by variable recruitment, growth, and mortality driving shifts in populations. Numerous studies have sought to elucidate these processes in both terrestrial and aquatic ecosystems to varying degrees of success. Abiotic and biotic factors operate at multiple spatial scales and interact in complex ways, creating complicated answers to important questions. The purpose of this study was to elucidate the mechanisms underlying recruitment of juvenile fish in the Middle Mississippi River. To do this, we utilized a regression residual analysis on long-term data to assess year-class strength for multiple species from 1993-2014. From this analysis, we determined that species-specific recruitment patterns correlate with seasonal variations in both abiotic and biotic factors. More specifically, water temperature, discharge, and precipitation had the greatest effect on recruitment patterns in the Middle Mississippi River. From this study we can then begin to predict year-class strength in various species from year-to-year. This is useful not only to biologists but also to commercial and recreational anglers who use the Middle Mississippi River.