Abundance

There’s a place called Chippewa Flowage, northern Wisconsin near Hayward. Folks head that way to fish. Maybe you’ve been?

Last time I was there it was towards the end of June. Two notable things were going on that day. Myself and Jeff Hanson, an environmental engineer fished the south side of the reservoir for largemouth bass. We landed 39 bass, and one northern pike. We also interviewed seven other boats of fisher people. They were all also fishing the south side. No one was fishing the north side. We checked a couple times. And, except for two boats fishing open water for walleye, everyone was focused on fishing around the perimeter of naturally occurring floating islands which, at least then, were all on the south side.

Surface area and circulation are the prime variables that define the wetland effect. Woody perennials like leatherleaf and labrador tea provide a matrix of surface area around these peat-based floating islands. The Chippewa River, as well as wind and waves (and boat wakes for that matter) provide circulation.

It’s simple enough. Microbes digest anything organic. They and their residue form biofilm. Small particles in water bond to biofilm. Algae bonds to it. The blend is called periphyton. It is the base of the food chain in fresh water. In the case of Chippewa Flowage there is a lot of edge habitat. It has granite outcroppings; it has sand, gravel, timber dead heads (providing timed-release carbon), all providing surface area. So, along with the floating islands, there’s a wealth of surface area.

When surface area combines with circulation and the natural nitrogen cycle in a waterway, it’s frequently a really good spot to fish. Not always. There’s always more to the story. We humans, for instance, are particularly adept at adding variables that truly complicate life. As we advance in monolithic lockstep towards a goal, or react in a less than thoughtful flavor-of-the-month mode, we tend to complicate life. Any life system that is highly specialized tends to suffer around us. But when these two primary variables come together, surface area and circulation, the stage is set for movement of nutrients and carbon through the food web.

The alternative is not pretty. When nutrients and carbon stack up, the wetland cycle is impinged, short-circuited. If there is not enough surface area and circulation there will be buildup or accumulation of at least one nutrient. Check out the graphic and note that the waterway’s potential for higher order biota production is diminished, perhaps even ended, when any of the primary nutrients stack up.

Chippewa Flowage is a Class A fishery. People come from all over the world to fish it. They catch huge volumes of walleye, northern pike, smallmouth bass, largemouth bass, crappie, perch, rock bass, and bluegill. Perhaps it is most famous for having produced the world record muskellunge, at 69 pounds, 15 ounces. The amazing feature of this waterway’s productivity is that it achieves this fish production without extra nutrients. It’s taking the natural nitrogen cycle, minimal phosphate addition, and cycling it. It’s a living example of the wetland effect, and the abundance it engenders. What potential levels of abundance might be achieved if we humans designed this wetland effect into our nutrient rich waterways?

Key bullet points:

  • Biocides kill biota. Is there such a thing as a species-specific biocide? Has anyone ever tested their biocide on the countless species of microbes that occur in fresh water?
  • Surface area and circulation enable nature’s wetland effect to move nutrients and carbon though the food web. The resulting abundance more than justifies careful stewardship.