By Andra Bryan Stefanoni
The creature known as H086 is so inconspicuous that she might have been mistaken for a rock on the bottom of Missouri’s Silver Fork River.
But she was discovered, transported to a science lab behind doors marked “restricted access” and put into refrigeration. She, along with dozens of others of her kind, is being closely monitored.
Their future is at stake.
A member of the freshwater mussel family, H086 is known as a fatmucket. She has many cousins — there are 300 species in North America, which has the highest diversity of freshwater mussels in the world. The rivers and streams of Missouri have historically had some of the largest populations of many kinds.
Incredibly, H086 can produce several million offspring in a year. Had she been left at the bottom of the river, few of them would have survived, making her among the country’s most imperiled native species. In a lab, her odds improve.
According to the Nature Conservancy, 70 percent of the mussels in North America have become extinct, compared with 16.5 percent of mammal species and 14.6 percent of bird species. In the Midwest, more than half of the 78 known species have been classified as federally endangered, threatened or in a state of concern.
But because they live at the bottom of waterways — far from sight of canoeists, anglers and passers-by — their critical role in the environment and the economy almost always is overlooked, researchers say.
“They are a hidden treasure,” said Bryan Simmons, a biologist and scuba diver with the U.S. Fish and Wildlife Service based at Missouri State University in Springfield.
Simmons, 42, has spent 20 years, and plans to spend many more, on not just the study of mussels, but on ensuring that their populations are healthy and robust in the future.
He grows animated when he holds H086, a plain, algae-covered specimen, and describes her intricate reproductive cycle, the many variables that are almost certain to end the life of most of her offspring, and the reason the public should be concerned for her survival.
Simmons worries that because mussels lack the charisma of other imperiled animals, such as the bald eagle, the public’s motivation to save them may be lacking.
But they are critically important to the environment, he said.
“A single adult mussel can filter about eight gallons of water a day,” he said. “They remove a lot of the stuff we pay millions and millions a year to remove artificially.
“They also are our canary in the coal mine — a bio-indicator of what’s happening in our environment. They are very intolerant to water quality problems, which means if they are declining, we should be concerned.”
Chris Barnhart, a national authority on mussels, and Simmons’ former teacher and now his colleague at Missouri State University, said mussels are “inconspicuous but surprisingly important.”
“Mussels are attracting particular attention from biologists and conservation agencies because they are sensitive to so many of the problems affecting streams, including pollution, erosion, siltation, impoundment and the introduction of alien species, such as zebra mussels,” Barnhart said.
Recent research shows that mussels are extremely sensitive to some pollutants, including ammonia, copper and pesticides.
“They can literally outweigh all other animals in rivers,” Barnhart said.
A hundred years ago, mussels were harvested commercially by the ton from Kansas and Missouri rivers for a burgeoning business: buttons. Noted scientists at the time, including two from Missouri, began studies and estimated harvest numbers out of concern for the mussels’ sustainability.
“Missouri was at the cutting edge for this,” Simmons said.
But more recent human activity in the state known for its rivers, lakes, agriculture and recreation began taking far greater a toll than the buttons of the 20th century ever did.
“When plastic was invented and they began using that for buttons, mussels weren’t harvested as much anymore,” Simmons said. “But then we dammed up the White River, one of the best mussel rivers in the world at one time, and mussels can’t survive in what essentially became a big swimming pool.”
Damming the Neosho River to create the John Redmond Reservoir in Coffey County, Kan., also had consequences: It kept fish, which play host to the parasitic larval stage of mussels, from reaching the upper end of the river to naturally replenish the population. There, cattle feedlots had dumped into the water large amounts of ammonia, which killed them.
In Southwest Missouri, the decline of two species, the Neosho mucket and the rabbitsfoot, is particularly alarming, an analysis by the U.S. Fish and Wildlife Service concluded.
Point source pollution, taking gravel from rivers to use for county roads, the removal of erosion control in order to plant crops near flood plains, and other man-made factors are to blame, Simmons said.
Barnhart, Simmons and graduate students have for several years been working to perfect homemade contraptions in their lab in order to propagate populations of declining mussels. At the same time, they are researching what food sources help mussels thrive and which fish play the best host to their developing young.
It’s tedious, but it’s working.
The university, the Missouri Department of Conservation and the U.S. Fish and Wildlife Service teamed up with the Kansas City Zoo a few years ago on a project to raise thousands of pink muckets, an endangered species, in a lagoon there.
The crews extracted eggs from pregnant mussels in their lab, transferred them to the gills of host fish in holding tanks for their larval stage of development, kept them alive through their juvenile stage with a complicated drip algae system, then released them to underwater “boats” that were made especially for them and placed into the lagoon.
When they reached adulthood, the team released the mussels into the Lower Osage River in central Missouri, where the mussel population had been negatively affected by the operation of Bagnell Dam near the Lake of the Ozarks.
Earlier this week, Barnhart retrieved 1,000 Neosho muckets from the zoo’s lagoon, and after Simmons used a laser engraver to mark each one, Barnhart released them in the Cottonwood River in Marion County, Kan., to replenish a dwindling population there.
“We have to keep adding genetics into the system,” Simmons said.