Date of this Version
Population density of five species of chubs and two species of minnows in the Missouri River in Nebraska has been reduced by as much as 95% since 1971. Burbot have been nearly extirpated, sauger have been greatly reduced, and blue catfish are rare. Reasons for the decline of these species include removal of snags from the river; cessation of organic matter and sediment transport because of the construction of large dams on the mainstem and tributaries; cutoff of floodplain connection through channelization, degradation, and the cessation of flooding; alteration of the natural hydrograph to meet the need for commercial navigation; and reduction of the natural water temperature regime because of deep release of cold water from the large reservoirs. We propose remedial actions for each of these ecological changes, and we propose listing of several species as endangered in Nebraska.