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Endangered Species Program
Conserving and restoring threatened and endangered species and their ecosystems
Pink Mucket (Lampsilis abrupta)
Lower Osage River Protection and Enhancement Plan
Relicensing the Bagnell Dam in Missouri is helping conserve and restore two endangered mussels, the pink mucket and scaleshell (Leptodea leptodon).
The Bagnell Dam on the Osage River created Lake of the Ozarks. Built in 1931, its initial operating license expired in 2006. Bagnell Dam is a hydroelectric dam operated by Ameren Missouri.
The new license, issued by the Federal Energy Regulatory Commission (FERC), incorporates a number of environmental features that address damages caused by the dam to downstream natural resources in the Lower Osage River.
Article 412 of FERC's license to AmerenUE for Bagnell Dam requires establishment of the Lower Osage River Protection and Enhancement Program1. The purpose of the Protection and Enhancement Program is to continue adaptive management actions to improve aquatic habitat, protect and improve aquatic resources, and reduce damaging effects of dam operation on the federally endangered pink mucket and scaleshell mussels in the lower Osage River. The program is funded annually by Ameren Missouri and began in 2008.
As part of the Protection and Enhancement Program, Program partners2 are propagating the federally endangered pink mucket and scaleshell mussels for release into the Lower Osage River.
Mussel beds with pink muckets are found near the mouth of the Osage River, but only a few individuals have been found further upstream. Releases will augment this existing population so that the pink mucket will occupy mussel beds throughout the Lower Osage below the Bagnell Dam.
Success of the mussel releases is dependent on habitat conservation measures included in the Bagnell Dam license that are expected to improve river conditions so that pink muckets can now survive throughout the Lower Osage. Those measures include improved minimum flows, increased dissolved oxygen levels in the lower river during project operation, gradual ramp-down rates to reduce bank and channel erosionafter flood flows, fish protection measures at the dam, and the Protection and Enhancment Plan.
In addition to the habitat conservation measures, the Protection and Enhancement Program includes monitoring that will allow researchers to evaluate success of the mussel releases and habitat improvement measures. Monitoring results will be used to adjust future conservation actions. Additionally, the knowledge gained from propagating and releasing pink muckets is expected to be used throughout the species range and help restore it back to health.
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1The Protection and Enhancement Program was agreed to by Ameren Missouri, the Missouri Department of Conservation, and the U.S. Fish and Wildlife Service (Service), then formalized as part of a Settlement Agreement filed with the Federal Energy Regulatory Commission (FERC). Terms of the Settlement Agreement were written into Ameren Missouri’s new project license issued by FERC on March 30, 2007.
2 Lower Osage River Protection and Enhancement Program partners include Ameren Missouri, HDR Inc., Iowa State University, Kansas City Zoo, Missouri Department of Conservation, Missouri State University, and the U.S. Fish and Wildlife Service.
Last updated: March 12, 2018