Biology, Management, and Culture of Walleye and Sauger

Chapter 3: Molecular Systematics of Sander, and Hybridization between Walleye and Sauger

Neil Billington and Brian L. Sloss


Sander and its percid relatives have been the subject of several phylogenetic inquiries. The purpose of this chapter is to focus on efforts to elucidate the intragenus and family-wide relationships using molecular genetic techniques. In addition to the currently recognized phylogenetic relations among Sander and other Percidae, a review of previous research is presented outlining the various methods and findings from key research into their evolution. A preview of future techniques and efforts is provided. The last half of this chapter is focused on hybridization between walleye and sauger and includes the occurrence of natural hybrids and methods used to detect the hybrids effectively, as well as brief reference to other Sander species hybrids.

The inherent value in understanding the phylogenetic relationships for a group of organisms is not always self-evident. Mayden and Wood (1995) suggested three primary roles of modern systematic biology: discovering natural diversity, determining patterns of natural order, and discerning relationships among the products of evolutionary descent. The analysis and discovery of phylogenetic histories enable us to investigate the evolutionary past of a group of organisms at many different levels (Maddison 1996). Understanding the evolution of specific organisms or groups of organisms mandates an accurate estimation of the relationships among these taxa. Without accurate sister-group relationships, studies attempting to partition characteristics such as behavior, morphology, ecology, physiology, and many other attributes of organisms as the result of historical constraint or as the result of independent divergence are speculative (Mayden and Wood 1995). The accurate construction of historical biogeographical distributions of taxa is reliant on an accurate phylogeny of the group of taxa being studied. Furthermore, hypotheses of phylogenetic relationships and biogeographical distribution allow researchers to examine the evolution of groups of organisms in relation to their origin, age of divergence, and probable patterns of dispersal (Mayden and Wood 1995). A comprehensive understanding of the evolution and diversification of taxonomic lineages can provide valuable insight into life history strategies, adaptability, and resilience to future perturbations.