Rainbow smelt (Osmerus mordax) influence on walleye (Sander vitreus) recruitment decline: mtDNA evidence supporting the predation hypothesis.

Rainbow smelt (Osmerus mordax) have been introduced widely but are associated with declines in walleye (Sander vitreus) recruitment. A primary hypothesis for these declines is that O. mordax consume larval S. vitreus. We confirmed overlapping spatial-temporal distributions of larval S. vitreus and O. mordax in our study system and used mtDNA analyses to determine if O. mordax stomach contents contained S. vitreus. Approximately 20% of O. mordax composite stomach samples were considered positive for S. vitreus consumption. These findings support the predation hypothesis and have S. vitreus management/stocking implications.