Life history variation parallels phylogeographical patterns in North American walleye Sander vitreus) populations

Walleye (Sander vitreus) is a native fish species in North America, and its zoogeographic range covers several climatic zones. Using multivariate statistical approaches and published growth data, we explored the association between climatic conditions (frost frequency, precipitation, air temperature, solar radiation, and cloud cover) and growth of walleye from 89 populations in North America. We found significant concordance between climatic conditions and walleye growth; however, the pattern of concordance differed among populations that originated from geographical regions that were colonized from different glacial refugia. This suggests that contemporary differences in walleye growth patterns related to local climatic conditions may have been shaped by evolutionary divergence that occurred among refugia during the last glaciation. We suggest that caution should be taken when assessing possible effects of climate variation and climate change on the life history traits of different walleye and other fish populations, especially when such assessments potentially include several genetically distinct groups. Procrustes analysis was shown to be an effective tool for characterizing how a multivariate set of response variables change in response to generalized changes in a multivariate set of independent variables.