Different Migratory Strategies of Invasive Common Carp and Native Northern Pike in the American Midwest Suggest an Opportunity for Selective Management Strategies

Inundated floodplains, backwaters, and wetlands are important spawning habitats for many freshwater fish. In Midwestern North America and areas of northern Europe, the Common Carp Cyprinus carpio and Northern Pike Esox lucius inhabit many of the same watersheds and perform migrations to interconnected wetlands during the spring to spawn. In this study, the movement patterns of adult Northern Pike and Common Carp from lakes into adjoining wetlands were assessed in Minnesota to determine how and when these species moved, and if Common Carp might be blocked or trapped without disrupting the Northern Pike. Adult Northern Pike migrated over an extended several-week period starting early each March, when temperatures were greater than 4ºC and when the fish were fully sexually mature (i.e., females were ovulated and running with eggs, and males were spermiating). In contrast, adult Common Carp migrated over relatively short time periods that lasted just a few days between April and June, and whose specific timing varied but always occurred after water temperatures rose to 10ºC and usually coincided with rain. Migrating Common Carp were in prespawning condition (i.e., females were not yet ovulated) and appeared to be homing as stream selection was very specific. Less than half of the Common Carp population migrated each year, reinforcing earlier observations that Common Carp likely conduct partial migrations. Overlap between Northern Pike and Common Carp was minimal, suggesting that management strategies using removable barriers, for example, could be used to control invasive Common Carp without affecting native Northern Pike populations.