On a hot summer day, you couldn't blame them. People wading the shallows off the wide sandbar had become just heads bobbing in the slow current. It made sense. They could stoop to comb through the sandy substrate. Or they could really get into their work. Most chose the latter; floating and pulling their way upstream as their hands felt back and forth for mussels. From the Department of Natural Resources, U.S. Fish & Wildlife Service, Black Hawk County Conservation Department and a local volunteer corps; they were learning to conduct a mussel population survey of this targeted sandbar and nearby river channel. At mid-channel a diver in a wetsuit provided some deep water backup.

And though literally immersed in their work, the results were nothing to brag about. "Historically, about 29 species of mussels have been found in this stretch of the Cedar River. Today? Well, we found two," was the word from DNR fisheries biologist Scott Gritters. Workers tallied 20 relatively common 'pocketbook' and five 'pimpleback' mussels in the meager haul.

The procedure was not complicated. "We are running our hands across the sand. We will feel the shell and pull the clam out of the sand or mud," explained biologist Denny Weiss. "If it is a live one, about half of it will be imbedded into the substrate. These dead ones will be in any shape or form, laying out on the bottom."

Another 10 species--ranging from fat mucket, pistol grip, giant floater and white heelsplitter were represented 'posthumously.' "Not dead long," admitted Gritters, as he looked over a somewhat rare 'Elk Toe.' "But it would sure be nice to find a live one, to make sure they're still out there."

In it's heyday, the mussel industry was a riverfront heavyweight in Iowa. Button factories thrived in places like Guttenberg and Muscatine prior to World War II and the advent of plastics. Old 'punched out' shells still litter the banks. Gritters suspects the Iowa, Wapsipinicon and other interior rivers were just as profitable. Old fisheries records show 25 tons harvested from the Cedar River between 1912-1914. "Prairie streams were once hotbeds for mussels. Some streams were covered from shore to shore. Now, we find just a sprinkling; like here today," Gritters noted. "If you walk the banks, you see dead shells and maybe think, 'they're living around here,' but actually search for them in the water and it's a different story."

Shells-when available--are still used in Asian cultured pearl industry. However, Iowa's interior streams are closed to clamming and officials are asking that the Mississippi be set off limits, too. Gritters says there is no clamming underway, anyway.

Most people don't bother thinking about clams. Others assume they are down there 'out of sight, out of mind,' perhaps. There is reason for heavy concern, though. "Mussels are a real good indicator of our water quality," Gritters warns. "They supply food to many fish. Wherever fish are; the riffles, the clean sandbars, there will be mussels. There is really an entire ecosystem down there. If we lose mussels over the long haul that tells us our water quality is somewhat contaminated. And if mussels decline, we know that fish populations do, too." Most of that contamination is sedimentation; soil runoff. Biologists also suspect pesticides have something to do with the disappearing ecosystem, They know that infestations of zebra mussels have taken a big toll, as well.

A smaller scale search of the Iowa River in Johnson County, a few days after the 'mussel beach' search on the Cedar, yielded substantially more mussels, including the rare Pistol Grip and Yellow Sandshell. Still, despite that occasional glimmer of hope, there is no guarantee of long term health. "It's a huge issue. Over the last decade, up to 90 percent of them have declined," noted Gritters. "Mussels are in a decline...a big time decline."

Higginseye Research Returns

Mussel researchers return to Iowa City this month to see if their experiment with endangered Higginseye clams has 'taken root' on the Iowa River. It's one of several culturing methods attempted on the Upper Mississippi and it's tributaries to save the species. For the past three summers, researchers captured local fish and literally inoculated glochidia--larval mussels--into the gills of fish, duplicating the process that takes place on mussel beds on the river's bottom. They will search prime habitat for small Higginseye, which may have fallen away from their hosts, as well as any signs of natural reproduction.

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