Threats to Paddlefish Habitat: Implications for Conservation
Joseph E. Gerken and Craig P. Paukert
Abstract.—Paddlefish Polyodon spathula are large, riverine fishes that occupy extensive home ranges and often migrate long distances in spring to spawn. As a result of these life history characteristics, paddlefish require many habitats to sustain their population over time. Largely as a result of anthropogenic activities, many of the habitats historically used by paddlefish have been altered or destroyed and remaining paddlefish habitats are being threatened by dam construction, channelization and dredging, and altered land use within watersheds. Understanding how habitat alteration may affect paddlefish populations, and identifying threats to current paddlefish habitat, is needed for the management of this species. We review the threats to paddlefish habitats and assess how anthropogenic habitat alterations, such as changes to natural hydrology through the construction of dams and channelization of large rivers or altered land-use patterns leading to increased sedimentation, have affected paddlefish populations. Recent river restoration and conservation measures that help protect and restore paddlefish habitats include fish passage structures and controlled water releases from dams to simulate a more natural hydrograph. New threats such as global climate change may alter paddlefish habitats in the future. Continued efforts to minimize the impact of anthropogenic changes to paddlefish habitats, and measures to restore natural riverine conditions, may help conserve vital habitats for paddlefish populations.