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University of Iowa News Release


Oct, 1, 2007

UI engineer to help release endangered mussels into Mississippi River Oct. 2

A freshwater mussel once plentiful along the muddy bottom of the Mississippi River was nearly wiped out in the late 19th and early 20th centuries by a booming demand for buttons and pearls. This week, a University of Iowa engineer will begin work to try to revive the population of the endangered Higgins Eye (Lampsilis Higginsii) pearly mussels.

At 2 p.m. Tuesday, Oct. 2, Tatsuaki Nakato will work with state and federal officials to release some 5,000 of the mollusks into the river near the UI's Lucille A. Carver Mississippi Riverside Environmental Research Station (LACMRERS) at Fairport, Iowa.

The goal is to bolster the small, native population of freshwater mussels, thereby enhancing the river basin's natural biodiversity and health, says Nakato, director of LACMRERS and research engineer at IIHR-Hydroscience & Engineering.

"Today, species of native mussels that survived the button industry of the 19th and early 20th centuries are being smothered by exotic zebra mussels -- small, prolific, and introduced to Midwestern waters in the ballast of transatlantic ships," he says. "In October 2003, a substantial number of adult and juvenile mussels, including the endangered Higgins Eye mussel, were discovered in an area known as Pool 16 near Buffalo, Iowa. We want to ensure that the bed continues to survive by promoting its growth."

The Higgins Eye pearly mussels will be released in Pool 16 of the Mississippi River near LACMRERS. The release site is especially advantageous because the Iowa Department of Natural Resources (DNR) Fisheries Management Office is located next door to the UI facility and will assist in monitoring the growth of the mussels.

Nakato says that the release is part of a plan by a group called the Mussel Coordination Team, which, for this event, is comprised of himself and fellow researchers: Tony Brady of the U.S. Fish & Wildlife Service; Bob Schanzle and Rich Lewis of the Illinois DNR; Bernard Schonhoff and Adam Thiese of the Iowa DNR; and Steve Johnson and Nicole McVay of the U.S. Army Corps of Engineers, Rock Island District. Nakato says that they hope to modestly increase the numbers of the mollusks living in the river where they had been abundant until the mid-19th and early 20th centuries.

According to the U.S. Fish and Wildlife Service Web site, a hunt for freshwater pearls on the Upper Mississippi River during the 1800s at times resembled the 1849 California Gold Rush in its intensity, with millions of mussels and entire mussel beds being eliminated. In 1889, German button-maker Johann Bopple developed the use of freshwater mussels as a raw material for buttons, and within 10 years there were some 60 button factories employing thousands of workers. By 1922, the freshwater mussel fishery was considered one of the largest and most profitable inland fisheries in the country. However, the mussel harvest dropped from more than 3,000 tons to just 150 tons between 1914 and 1929 as mussel beds were decimated.

The demand for the mussels continues to this day. From 1950 to the present, a multi-billion dollar industry has existed in which Japanese pearl firms harvest mussels and ship the mussels' shells to Japan, where round beads made from the shells are used as seed stock in marine oysters to produce very high quality cultured pearls. It takes almost a ton of shell to produce just 40 to 60 pounds of pearl nuclei.

"In the five years since LACMRERS was opened in May 2002, I have eagerly worked with state and federal biologists along the Upper Mississippi River, practically becoming a malacologist in the process," Nakato says. "I personally wanted to have the mussels released near the UI research station. I love to work on freshwater mussels."

Nakato says his work to study and help restore diversity to parts of the river is only beginning. He notes that he has collected, cleaned and finished over 40 freshwater mussel species from various Mississippi River sites for display at LACMRERS.

Nakato helped inspire the creation of LACMRERS, which opened in May 2002 and currently provides a place where physical and biological scientists examine the multifaceted problems that plague the Upper Mississippi River -- the river's stretch from St. Paul, Minn., to Cairo, Ill. The $1.5 million, 7,500 square-foot facility -- funded largely by the Roy J. Carver Charitable Trust in Muscatine, Iowa -- hosts engineers, biologists, geologists and other researchers.

IIHR is one of the world's premier and oldest fluids research and engineering laboratories. Students and visitors from around the world come to IIHR to study and conduct research, as well as carry acquired expertise back to their home countries.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500

MEDIA CONTACTS: Tatsuaki Nakato, LACMRERS, 563-288-2888,; Gary Galluzzo, University News Services, 319-384-0009,