Early Life Stage Investigations of Fish Recruitment in the North American Great Lakes: Misconceptions and Contributions to General Recruitment Theory

Our general understanding of the fish recruitment process has mostly derived from a large and continually growing number of early life stage investigations conducted in marine ecosystems. Comparatively fewer early life stage investigations have been conducted in large lakes, with little effort spent helping to understand 1) how the recruitment process compares between marine and freshwater ecosystems or 2) how freshwater studies have contributed to general recruitment theory. Herein, we seek to fill in this information gap in two ways.  First, we glean general insights from the small but growing number of Great Lakes recruitment investigations that have focused on early life stages. Specifically, we illustrate how recruitment of ecologically and economically important species can sometimes be regulated more by processes operating during the larval stage than the juvenile stage, which is similar to marine ecosystems but counters current conventional wisdom. Second, we illustrate how Great Lakes early life stage investigations have advanced our general understanding of the recruitment process, especially in the face of simultaneous, human-driven ecosystem stressors (e.g., nutrient abatement, invasive species). Our findings highlight the need for more early life stage studies in large lake ecosystems and continued erosion of barriers between marine and freshwater recruitment science.