Northern Prairie Wildlife Research Center
Description: This species is an ancient, large (up to 7 feet, 213.4 cm fish with a greatly elongated paddle-shaped snout (also called a spoonbill and shovelnose cat) and a large mouth on the extreme underside of its head. The tail fin is deeply forked with a long upper lobe. The paddlefish has skin without scales except for a patch near the tail fin.
Habitat and Habits: The paddlefish occurs in quiet, slow-flowing waters, swimming continuously near the surface or in shallow waters. It feeds on zooplankton and insect larvae that it filters from the water through its elaborate gill rakers.
Males mature at about 7 years, females at 9-10 years. Paddlefish spawn in early spring on gravel bars of large, free-flowing rivers. Spawning is not successful without flooding at critical times. Eggs sink to the bottom, adhere to the first object contacted and hatch approximately 9 days later.
Paddlefish are long-lived, some reaching over 30 years of age. This species was formerly the most commercially important fish in the Misssissippi Valley, prized for its meat and caviar.
Distribution: The paddlefish is one of two living species of this family in the world. The other species in the family Polyodontidae is found in China's Yangtze Valley. Paddlefish are restricted to the Mississippi River and its tributaries and adjacent Gulf drainages in portions of Texas and Alabama. Under former natural conditions, the numerous oxbows and backwaters of the large, free-flowing rivers of the Mississippi Valley provided feeding grounds as well as extensive spawning habitat (gravel bars). In South Dakota, a stable paddlefish population occurs in the Missouri River below Gavins Point Dam, with remnant populations in other Missouri River reservoirs in the state.
Conservation Measures: Like the pallid sturgeon, restriction of natural migration and loss of habitat due to flood control impoundments have affected the paddlefish. Poaching continues to threaten this species. South Dakota has an extensive history of paddlefish research and management and is currently one of only a few states with a successful artificial propagation program.