Northern pike are soft-rayed fish with no adipose fin, and one dorsal fin which is positioned towards the tail. They are quite long in proportion to depth and width, and have a flattened snout. Adult pike spawn in the spring in shallow, weedy, flooded areas of rivers, marshes and bays of large lakes. Pike are found throughout the year in shallow water due to their ability to tolerate higher water temperatures, lower concentrations of oxygen and higher concentrations of carbon dioxide than many species of freshwater fish. They generally lie motionless and well camouflaged among the shallow water vegetation, waiting to pounce on anything that swims too close.