Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
The endangerd pink mucket gets a boost in recovery on the Osage River, Missouri
Midwest Region, June 20, 2012
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Juvenile pink muckets were tagged prior to their release into the Osage River.
Juvenile pink muckets were tagged prior to their release into the Osage River. - Photo Credit: Josh Hundley (USFWS)
The Service's Bryan Simmons and Wyatt Doyle place pink muckets in quadrats in the Osage River.
The Service's Bryan Simmons and Wyatt Doyle place pink muckets in quadrats in the Osage River. - Photo Credit: Heather Calkins (USFWS)

The pink mucket pearly mussel was listed as an endangered species primarily because of the construction of dams on many rivers throughout its range. The species cannot survive in lakes created by dams, and they struggle to persist downstream where the river environment is altered by dam operations. The Osage River Basin in central Missouri is no exception, with four major reservoirs constructed in the mid- to late-1900’s.


A population of pink muckets still survives in the lowest reach of Osage River below Bagnell Dam, owned by Ameren Missouri. However, the species is rare because of the effects of power generation at the dam, which alters the natural flow and water quality of the river downstream. In 2007, Ameren Missouri made major changes to their operation to lessen these impacts and funded a program administered by the U.S. Fish and Wildlife Service to artificially propagate pink muckets to help increase their population to a more sustainable level.

In June of 2012, the pink mucket population in the lower Osage River received a boost in their recovery when Columbia Missouri Field Office – Ecological Services and Columbia Fish and Wildlife Conservation Office - Fisheries, along with assistance from Ameren Missouri and the Kansas City Zoo, released over 3,000 pink muckets into the lower Osage River. These animals were propagated at Missouri State University from adults collected from the Osage River last year. The juveniles where then transferred to a rearing facility at the Kansas City Zoo to continue growing. While at the zoo, the shell of each individual was laser engraved with a unique identification number for future monitoring purposes.

Releasing mussels into the wild requires more effort, but is less dramatic than for most other animals. Birds fly away from caring hands and fish quickly swim off to their new homes. If mussels were released in a similar fashion, they would simply drop to the stream bottom and sit like a rock. Mussels cannot swim away to find suitable habitat, and like their snail relatives, move slowly, especially if stressed from transport. They also need to live in the gravel on the stream bottom to hide from predators and avoid being swept away in the current. To prevent being immediately spotted by hungry raccoons and fish or swept away by the next high flow from power generation, each of the 3,000 mussels had to be hand placed into the substrate. This task takes time, but allows the juvenile pink muckets time to adjust to their new environment. Because mussels live in aggregations called mussel beds, you could say releasing them is like tucking them into bed. Hand placing them in a known location not only increases their chances of survival, but allows their survival, growth and movements to be easily monitored in the future.

This effort was the second release of propagated pink muckets on the Osage River. A similar release was conducted at the same location in the fall of 2011. These animals have already been surveyed and appear to be healthy and growing. Because of the released animals, this site has more living pink muckets than any other known site in Missouri.

Contact Info: Joshua Hundley, 573-234-2132 x176, joshua_hundley@fws.gov
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