The sauger (Sander canadensis) is a freshwater perciform fish of the family Percidae which resembles its close relative the walleye. They are members of the largest vertebrate order, Perciformes. They are the most migratory percid species in North America. Saugers obtain two dorsal fins, the first is spiny and the posterior dorsal fin is a soft-rayed fin. Their paired fins are in the thoracic position and their caudal fin is truncated which means squared off at the corners, a characteristic of the Percidae family. Another physical characteristic of Saugers are their ctenoid scales which is common in advanced fishes. Saugers have a fusiform body structure, and as a result saugers are well adapted predatory fishes and are capable of swimming into fast currents with minimal drag on their bodies. They may be distinguished from walleyes by the distinctly spotted dorsal fin, by the lack of a white splotch on the caudal fin, by the rough skin over their gill, and by their generally more brassy color, or darker (almost black) color in some regions. The average sauger in an angler's creel is 300 to 400 g (11 to 14 oz) in weight.