The paddlefish is one of the few freshwater fish to feed by straining plankton from the water, which it does by sweeping through the water with its lower jaw dropped and the sides of the head inflated (4), allowing it to filter feed and ventilate its gills simultaneously (7). The large snout is covered with electroreceptors used to gather information about the surrounding environment, including locating prey (7). The peak breeding season occurs in spring, during which large shoals of paddlefish migrate upstream and congregate in specific breeding areas to spawn. Spawning appears to require very specific environmental requirements and therefore generally only occurs every two to three years based on environmental stimuli (7). Single females can lay a huge number of eggs, from 300,000 to 600,000 (8), after which no parental care is invested and many will die (7). Males attain sexual maturity in around seven years, females in nine to ten (9). These relatively long-lived fish may live up to 55 years, although the average lifespan seems to be around 20 to 30 years (7).