Mussels of the Kishwaukee surveyed
By Jamie Johannsen
Director of Marketing and Public Relations, Winnebago County Forest Preserve District
Visitors to the Kishwaukee River the week of Aug. 10 may have been surprised to see a dozen men and women crawling through the water on hands and knees, scrabbling through the gravely river bottom like raccoons.
For three consecutive days, biologists from the Illinois Department of Natural Resources (IDNR) and the Illinois Nature Preserves Commission (INPC) worked with Winnebago County Forest Preserve District staff and other volunteers to survey the north and south branches of the Kishwaukee River for mussels. According to Bob Szafoni, IDNR Natural Areas project manager, it has been at least 10 years since the last mussel survey of the Kishwaukee.
The purpose of the survey is to provide data about the number of mussels and number of different mussels species in the river.
“Mussels are sensitive barometers of environmental quality,” said Mike Groves, Natural Resource manager for the Winnebago County Forest Preserve District. “The status of mussel populations present in the water is a widely-accepted measure of the stream’s overall biological health.”
Szafoni led the survey effort and coordinated the work of 16 volunteers from various local conservation agencies. Szafoni explained mussel populations are very important to aquatic biologists because, “unlike fish, mussels can’t move when there is a pollution event, a change in water quality or an increase in sedimentation; the mussels are stuck there, and have to absorb it.”
John Nelson, Natural Areas Preservation specialist with the INPC, added, “If we see a stream that has high-quality mussels, lots of different kinds (10 or more species), and good numbers of individuals, we can conclude that the stream is still in good shape.”
Nelson assisted Szafoni in supervising daily teams of volunteer surveyors from the Winnebago County Forest Preserve District, Boone County Conservation District, the Rockford Park District, and the Natural Land Institute, as well as other individuals.
Many of the volunteer crew members hold degrees in conservation, wildlife biology, or natural resource protection. Yet, all of them discovered mussel species identification is very tricky. As each volunteer’s bag was emptied, the crew attempted to identify each live mussel according to its characteristics.
Szofoni watched, quizzed and coached as the volunteers honed their specie identification skills by looking carefully at color, shape, structure, and texture of the various shells, and also distinguishing features of the internal organism visible through the crevice of an open shell.
Andy Bacon, stewardship director for the Natural Land Institute, remarked that half the fun of learning about freshwater mussels is their colorful and whimsical names. Common mussel names such as plain pocketbook, pimpleback, fragile paper shell, pistol grip and white heelsplitter tripped off the tongues of the volunteers as they worked to correctly identify and sort.
As each animal was positively identified, it was added to its specie pile on the ground. Empty shells of dead organisms were relegated to a separate pile. Volunteers then quickly counted each pile of sorted mussels, and the biologists recorded the species, quantity, location and any special notes, such as “female actively displaying.” As soon as data were recorded, the volunteers quickly and carefully returned the mussels to the riverbed. Data about the empty shells were also recorded because, according to Szafoni, they may indicate a particular species was formerly living in this river, although no living organisms have been recently collected.
At various survey points, Szafoni’s excitement about the success of the mussel hunt was obvious. His exclamations and enthusiastic whoops elicited grins from the dripping wet volunteers as they dumped their mesh bags of bivalve treasure on the shore. Szafoni described the survey as highly successful.
At the conclusion of the survey, mussels had been collected, identified and documented at 14 stations throughout Winnebago and Boone counties. Good numbers of mussels and nice diversity were found. In total, 16 species of live mussels were documented (19 species, including dead shells).
Three species of endangered mussels were found and in healthy quantities. To Nelson, this indicates “the Kishwaukee River has good water quality and is ecologically significant in the region; I would go so far as to say it is biologically significant in the state.”
In fact, Szafoni says that if he were to create a David Letterman “Top Ten List” of Illinois rivers, the Kishwaukee would definitely be on it. “I have done a lot of musseling in Illinois, and this Kishwaukee trip has been one of the most rewarding as far as finding nice, healthy numbers of mussels and mussel diversity, including endangered species,” Szafoni says.
In a snapshot analysis, Szafoni states that natural channel, natural flow, good water quality and intact buffers are the qualities that allow a river to reach its highest potential, and said, “the Kish is darn near meeting that.” Szafoni attributes the river’s relatively healthy condition to the fact it has not been significantly disturbed or degraded by human activity, adding, “Streams do really well when we don’t do things to straighten them, channelize them or interfere with their natural functions.”
The Kishwaukee has access to its floodplain. The river can handle storm events by cresting, overflowing into the floodplain and spreading out, dissipating water volume and velocity. The river’s natural rhythms maintain a healthy equilibrium for the water quality, river bed structure and surrounding plants and animals. In many river watersheds, Szofani comments: “Humans have used up the land right up to the river’s edge, which degrades its water quality, biological diversity and structure. So, the river becomes our enemy rather than a means for safely conveying the water downstream.”
In addition, John Nelson notes, “Every stretch of the river we surveyed has its riparian (native vegetation) zone intact, which filters out pollutants, run-off and sediment.”
As a prescription for continued health, these two experts agree, it all comes down to land use decisions and community development that incorporates watershed protection strategies.
Freshwater mussels are unique in that their larvae, called glochidia, must live for a time as a parasite on a fish. To increase the chances their young will find and attach to a fish host, some types of female mussels display tissues that mimic a small-prey fish to try to lure fish to swim near them. When she senses a fish of the right species nearby, she releases her young into the water so they can attach to the fish. To increase the chances of their young making contact with a fish host, some females “go fishing.” By displaying specially-adapted tissues that look like fish prey, they try to lure fish to swim near them. Sensing a fish nearby, the female releases her young into the water, ready to clamp onto the fish. To finish growing into an adult, glochidia need to latch on to the gills, skin or fin of a passing fish, and stay there, feeding for up to three months.
Some species of mussels require a specific species of host fish to survive. In the end, only one out of 100 glochidia will make it, one reason efforts to protect the health and quality of the Kishwaukee River are so important.
from the Aug. 26-Sept. 1, 2009 issue
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