The Lake Where You Live

We don’t fish for them. We rarely see them. We don’t know their names; if we encounter them at all, maybe we just call them “minnows.”

They are the multiple species of little fish that live in the near-shore shallows of our lakes, and they are a lot more important than most of us know. At least that’s the take-away from a session given last week at the Wisconsin Lakes and Rivers Convention given by Dave Marshal of Underwater Habitat Investigations and Lianna Spencer of the Lake Ripley Management District in Jefferson County.

The small fish we’re talking about here are not the juvenile stages of walleyes, bass, perch and panfish, which of course are important in their own right. We’re looking at species with names like least darter, pugnose minnow, tadpole madtom and brook silverside. 

Spencer reported that an extensive sampling of 420-acre Lake Ripley, a productive largemouth bass fishery, turned up a total of 37 fish species, many of them of the small near-shore variety.

The species in question generally don’t grow to more than a couple of inches long. But they matter because, the presenters said, they are like the proverbial canaries in the coal mine. They are sensitive to water quality, and their relative abundance can tell us a lot about the health of a lake, and especially its near-shore habitat. And they do provide forage for the fish we pursue for our sport and our dinner tables.

These little fish tend to be affected negatively by the presence of piers, which shade the water, and by other shoreline development and associated human activity. Relatively deep water abutting rock riprap can be detrimental to them because in the absence of extreme shallows near shore, they lose an escape hatch from pursuit by larger game fish.

In addition, the lowering of lake levels, such as by seasonal drought or drawdown by pumping from high-capacity wells, can rob these fish of access to spawning sites in adjoining marshes. They can also be stressed by wakes from powered boats, which carry more energy than natural wind-generated waves.

Lake scientists sample for these seldom-seen fish using low-power electroshocking and various kinds of small-mesh nets. It’s not as glamorous as surveying for fish like walleyes, northern pike, and muskies, but it’s an essential part of assessing lake health.

There are a few deeper lessons from presentations like the one given by Marshall and Spencer. One is that to learn about lake health we need to look beyond factors we can easily and routinely observe. Another is that lake ecosystems are built on a multitude of interlocking relationships among things living and nonliving.

As a final note, someone in the audience came up with a question that was begging to be asked throughout the talk: “What would you say about these little fish to shoreline property owners who only care about game fish?” 

And Marshall responded simply: “Game fish have to eat.”

Ted Rulseh, a writer, author and advocate for lake protection, lives on Birch Lake in Oneida County. Visit him and his blog at https://thelakeguy.net.