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Endangered Species Program
Conserving and restoring threatened and endangered species and their ecosystems
Pink Mucket (Lampsilis abrupta)
Propagation and Augmentation in the Lower Osage River
Numbers of juvenile pink muckets successfully propagated for release into the Lower Osage River have astounded project partners1.
Partners are propagating pink mucket freshwater mussels for release into the Lower Osage River, below the Bagnell Dam, as part of the Lower Osage River Protection and Enhancement Program. Releases of the mussels will augment the existing population. Habitat enhancment actions, taken as part of the Protection and Enhancement Program, are expected to improve river conditions below the Bagnell Dam so that pink muckets can re-establish throughout the Lower Osage River.
The propagation effort is so successful that the partners released mussels into the Osage ahead of schedule. About 3,000 juvenile pink muckets were released in the fall of 2011. Since then, the mussels grew faster than expected and another 3,000 pink muckets were released on June 20, 2012. We expect to release another 6,000 during the fall of 2012.
Gravid pink muckets were collected during late fall from the Lower Osage River and used to inoculate largemouth bass with glochidia. (See Reproductive Life Cycle of Mussels for an explanation of fish in mussel reproduction.) Inoculated largemouth bass were relocated from Missouri DOC's Chesapeake Fish Hatchery to Missouri State University. Glochidia matured, fell from the bass, and over 78,000 juvenile mussels were collected. The most difficult phase of mussel culture is during the first weeks and months while the juveniles are the smallest, most vulnerable, and prone to loss or disease. As expected, mortality was high but the number of mussels surviving was normal.
During late May and early June juvenile mussels were transferred to the Kansas City Zoo because the University does not have facilities to grow out such large numbers of mussels. Researchers constantly modified conditions and methods with the result that survivorship was higher than expected and the mussels grew much faster than expected. By summer's end in 2011 there were over 10,000 pink muckets in cultivation.
Release into the Osage River
During the first year of the project (2009), about 200 young mussels were produced. The second year, over 12,000 mussels were produced. Lessons learned during the first year helped researchers adjust their techniques to attain this success.
On October 20, 2011 the Missouri Department of Conservation and U.S. Fish and Wildlife Service released 2,676 sub-adult pink muckets into the Lower Osage River. Divers marked a large area of the river bottom. Within that large area, they established a grid of 1 meter squares and within each square placed 8 mussels. Each mussel was laser engraved with the year of release and a unique number. The engraving will allow researchers to monitor results of this and future releases. During future river surveys, collection of marked individuals will provide information on movement, growth, survivability, and population size.
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1Partners involved in propagating the pink mucket and scaleshell mussels include Iowa State University, Kansas City Zoo, Missouri Department of Conservation, Missouri State University, and the U.S. Fish and Wildlife Service.
Last updated: October 10, 2018