URBANA — When you're a mussel and you absolutely positively have to get from the Allegheny River in Pennsylvania to a holding tank at the University of Illinois as soon as possible, call research scientists Kevin Cummings and Jeremy Tiemann with the Illinois Natural History Survey.
"We're like the mussel FedEx people," said Cummings.
Last week, while thousands of University of Illinois students were gearing up for move-in day, Cummings and Tiemann were moving 1,200 endangered northern riffleshell and clubshell mussels into their new UI campus digs.
Thousands of mussels are being relocated from a section of the Allegheny River beneath a bridge that's slated for replacement in 2018. The old bridge will be dropped into the water, which could kill the mussels below, and temporary structures built into the river bed during construction would also threaten them. So Pennsylvania state agencies along with the U.S. Fish and Wildlife Service are relocating as many as possible.
Last week, about 4,000 endangered northern riffleshell and clubshell mussels were gathered from the Allegheny riverbed by officials from Illinois — including Cummings and Tiemann — West Virginia and Ohio, for relocation in their respective states.
Since move-in day, the 1,000 northern riffleshell and 200 club shell mussels have been in quarantine in holding tanks with flowing water on the UI campus where they're fed once a day, awaiting their next move in a couple weeks to their permanent digs in the Salt Fork and Middle Fork rivers.
The relocation works well with the mussel recovery plans of the Illinois Department of Natural Resources and U.S. Fish and Wildlife.
In 2005-06, the two agencies began to implement the plan to restore the northern riffleshell and clubshell species to their historical portions and ranges in Illinois, and the Middle Fork River was chosen as a target basin for the project, Tiemann said. The sites were chosen based on fish density and whether they were protected land, such as park property.
Both species need fish, certain types of fish, because their larvae, called glochidia, attach to the gills of fish. The northern riffleshell needs the bluebreast darter, which is also an endangered species, Tiemann said, but northern riffleshell larvae also can attach to other darters, and the clubshell needs a variety of minnows, and may use darters, too.
In 2010, the first batch of northern riffleshells were delivered, about 140 of them, and one half went to the Middle Fork and the other half to the Salt Fork. Each mussel has a passive integrative transponder tag that sends out a radio signal that the scientists can detect with a wand, allowing them to monitor them.
After a year and a half, 80 percent of them were still alive, which is on par, Tiemann said, with the results observed in Ohio, so U.S. Fish and Wildlife officials were pleased with the local results and approved the relocation of more.
Cummings and Tiemann participated in the gathering process that took about four hours for divers and snorkelers to scour the river bottom for 4,000 mussels.
Cummings said there more than 50,000 mussels in the area of the bridge that carries Route 62 over the Allegheny in northwestern Pennsylvania. Several endangered species of mussels are in that area, but the relocation is mostly focusing on the northern riffleshell.
"It's the only place in the world with such a concentration (of the northern riffleshell mussels). It's a beautiful, beautiful stream," Cummings said, adding that the high concentration is likely due to it having the nice, clean habitat necessary for mussels to thrive.
For the trip from the Allegheny, the mussels traveled to Illinois on ice in five 54-quart Coleman coolers wrapped in wet towels, all to help keep them cool, basically shutting them down physiologically until they arrived on campus about 10 hours later.
Originally, Cummings said, the plan was to transport them in the pull-behind trailer, but concerned with keeping them cool in such hot weather, they shifted all their luggage to the trailer, and moved the 1,200 mussels into the Chevrolet Suburban SUV with the five of them.
Just before their next move, the mussels will be numbered and tagged, and a day later, loaded into coolers again for the trip to the spots along the Salt Fork and Middle Fork where they will be acclimated to the stream temperatures and embedded into their new environment a little farther west than the Allegheny.
About the mussels
Riffleshell and clubshell mussels are freshwater mussels. Freshwater mussels, also referred to as clams, are one of the most endangered groups of animals in North America and a good indicator of water quality. Surveys in the past few decades have identified significant declines in mussel populations. Several factors are thought to be responsible for the decline, including overharvest, siltation of their habitat from agriculture, competition from exotic species like the zebra mussel and pollution by herbicides, pesticides and other chemicals. As a result, many mussels have been designated as state-endangered or federally endangered species.
Mussels live in the mud, sand or gravel in rivers and streams with some found in ponds or lakes. When mussels reproduce, their larvae, or glochidia, are expelled into the water to attach to a host, usually a fish, connecting to the gills or fins. Some mussels are host-specific while others use a wide variety fish. While attached, the larvae change form and begin to resemble adults. Eventually the small, young mussels break free and drop to the stream or lake bottom to begin an independent life. Mussels are an important food source for many animals, including muskrats, minks, otters, fish and some birds. Large piles of freshly cleaned mussels, called middens, can be found along the banks of a river or lake where muskrats are actively foraging.
Source: Illinois Natural History Survey