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On a gray weekday morning, I drove to Hidden Falls to meet Davis in the flesh. Lanky with curly gray hair and bright green eyes, Davis oozes enthusiasm for the river. As we trolled upstream, he explained that he had spent most of his life around the Mississippi. On and off for a decade, he worked as a commercial fisherman near Wabasha, where he netted carp for sale on the East Coast gefilte fish market. In his younger days, Davis, who is 53, was also a hunter and sport fisherman--hobbies subsequently supplanted by berry picking and nature photography. "Same itch, different scratch," he explained. In 1987, he decided to put a biology degree to work and landed a job at the DNR, where he now specializes in the ecology of the Mississippi and, lately, in freshwater mussels.
The mussels are one reason Davis wanted to come to the Twin Cities. Historically, Pool 2--the stretch of river from Hidden Falls to Hastings--was home to some 40 species of mussel. Over the course of the past century, that number has dropped by half. The decline has several causes. Because mussels are immobile, Davis points out, they are especially vulnerable to degradation in water quality. And then there is the problem of commercial over-harvest. In the late 19th century, a German businessman named J.F. Boepple came to the U.S., where he discovered that the shells of many of the native mussels could be used to manufacture buttons. The button-cutting industry boomed for several decades before plastic replaced the shells as a prime button material. Boepple would not live to see that day; while prospecting for mussels in Indiana, he stepped on a sharp shell, likely one from the aptly named Pink Heelsplitter, developed an infection, and died. "Karmic justice," Davis said with a laugh as he recounted the tale. Whatever the case, the mussels' reprieve proved short-lived. Worsening pollution and a new industry--the cultured-pearl business--took their toll.
As a result of all this, freshwater mussels are now widely regarded as North America's most endangered animal group. For the past few years, Davis has spearheaded an effort to reestablish some of the missing species, including the federally endangered Higgins eye mussel. To this end, he recently transported a dozen or so largemouth bass to Hidden Falls park and placed the fish in wire mesh cages in the river. The bass, he explained, carried the larvae of Higgins eye mussels in their gills. Over the course of the summer, Davis hoped, the mussels would mature, drop from the gills of the fish, and become the seed for a new population.
On our day on the river, Davis only wanted to see whether the cages had been carried away by the heavy currents from the summer rains. "They're out here somewhere. Twenty-two cages sitting on the bottom of the river," he said, peering into a depth finder in an effort to spot the cages. As it turned out, the search was futile. Davis didn't seem much concerned. He would simply come back with scuba gear and search the waters next month. A few weeks later, he did return, with a diver from the U.S. Fish and Wildlife Service. Together they located the cages, one of which they pulled from the water. After sifting through the mud, they found six juvenile Higgins eye mussels. "For the first time in 100 years, we can say that there are actually Higgins eyes in Pool 1," Davis exclaimed as he held up one of the tiny creatures.
When Davis first visited the gorge in the '70s, much of the river was a dead zone. When he came back about five years ago, he was shocked to see how much the water quality had improved. That got him thinking about other aspects of the river's potential. With the removal of the dams and some improvements to the city's storm-water sewers, Davis believes that the urban Mississippi could return to something resembling its natural state. "You aren't going to get back what once was. But with good hydrologists and good engineers, you could put back something with a lot of ecological value." That, he noted, is less possible in the parts of the river south of the confluence with the badly degraded Minnesota River.
As we moved up the river, Davis paused to imagine the gorge restored. He had no idea what the undertaking would cost. I volunteered that the removal of the Edwards Dam in Maine--a dam of comparable dimensions to the dam at Lower St. Anthony--cost around $3 million. Davis appeared encouraged by the figure. It doesn't seem impossible, he said, certainly no more daunting than the construction of locks and dams must have seemed in the 19th century, when Minneapolis city fathers cast a jealous eye on St. Paul. "Those people had a vision for the river. There were a lot of people who embraced it, and there were a lot of people saying, 'It's impossible,'" Davis said. "Well, hey, here's a vision for this century. The river doesn't have to be like this. And, you know, the corps is always looking for something to do. This could be a good project for them."