By Nick Simonson
The water was clear. Sure, it was finally spring and the ice came off the lake late this year, and like any stretch after that momentous occasion, the water was always crystal clear. Ripping a few flies through the shallows on the even of opener to see how my handiwork looked after a season behind the vise, I was amazed to see every flicker of bucktail and feather and even the tiniest shimmer of krystal flash in my streamers above the golden-brown sands in Big Detroit Lake.
As I wound up the last of the fluorescent line into the reel, I turned to the lifts to inspect the wear of winter, and as I did, another thing became crystal clear and perhaps was the reason for why the water seemed even more so than in past springs. All along the two-by-six metal bar, patches of gray came into focus as I approached the beached lift.
The thickening and thinning line wound up and over and under the metal frame and down the bent legs and it suddenly became evident what I was looking at, like some piece of abstract art made by tiny dots that suddenly turns into a picture when focused on from a different length. The twisting gray mass was an amalgamation of small shells, now dead with winter’s cold and the dry bitter north wind taking their life and leaving them attached by the filaments that bound them together in the winding line that symbolized the battlefront all anglers and conservationists now find themselves on. I scraped them loose from a fine netting that held them to the posts and inspected them with a sudden horrible realization that brought the headlines back from the dusty corners of my mind regarding an unpleasant discovery in the Pelican River and Red River a decade or so ago.
They were zebra mussels; the poster children of invasive species, and some long-descended generations of the first of the tiny, razor-sharp mollusks that were discharged into the Great Lakes from the visiting Russian and Caspian freighters’ ballast more than thirty years ago. Since that time, through boaters, anglers, bait buckets and other forms of transport of affected water, the microscopic larvae made their way from the middle of the continent to nearly every state in the nation, changing the face of fishing and aquatic recreation through their mere presence. It was hard to believe they had gone from ghostly sighting to covering an entire boatlift in just a few seasons.
A single specimen, no bigger than a fingernail, can filter a liter of water every day. Just one zebra mussel can release over a million eggs each year. Without having to put pencil to paper, it’s easy to see how fast they can have an impact on a fishery. While clearer water is normally a good thing, in this case, it’s bad. The rapid and incredibly efficient removal of algae, tiny particles and other nutrients from the water by an expanding zebra mussel population removes the base of the food chain, which eliminates food for insects and developing populations of minnows and panfish and the ripple eventually hits game fish populations as well, until ultimately the biome is altered altogether. With the mussels’ natural predators half a world away, and nothing locally to control the population, the change will be permanent on any American water where these creatures take hold.
The clearing water in lakes where zebra mussels have become established has shifted fish patterns as well, making angling more difficult. Where walleyes could stand the light of day in shallower water in the Great Lakes, they are now found ten, twenty or thirty feet deeper than just a decade ago. The same goes for smallmouth bass, which now forage on a growing round goby population (also an invasive) in the depths of the big waters. The population of zebra mussels, which have a five-year lifespan, is so great that on many beaches on Lake Michigan, piles of their tiny, razor-like shells have covered or altogether replaced shoreline sand. Extrapolate this out to any water where one is found in a DNR search or a Game and Fish survey, on a much smaller scale, and it’ll be a matter of years – not decades – before area anglers see the impact and feel it in their fishing.
After a particularly windy day this past weekend, where a streaming north wind pounded the shoreline and loaded up the lake’s early season debris on the sand, I wandered down the beach with the dogs just after dawn. There, just a few inches above the calm edge of the water, was a fine blue-gray line in the sand. The symbolism wasn’t lost in that moment either, as I inspected and found the ribbon of color consisted of the dead and smashed shells of the lake’s growing population of the invaders. Pulling the boat out and meeting the ANS surveyor at the launch later in the morning, I expressed my dismay at how quickly the zebra mussels had become established and what I had seen.
With a sigh, he replied, “at this point man, we’re just trying to slow them down and even that’s going to take everyone doing what they can – cleaning, draining, drying and paying attention,” adding his concern for the smaller lakes around the area and those downstream from the water just behind us.
With a shake of his hand and a sigh of my own, I thanked him for doing what he could, knowing that we had crossed a line that served as a point of no return for a place dear to my heart, and it had now shifted to another water that someone cares equally for…in our outdoors.
(Featured Photo: The blue, hatchet-shaped shells of dead zebra mussels make up the bulk of a debris line on the shore of Big Detroit Lake, Minn. after a windy day. On waters such as Lake Michigan, entire shorelines are now comprised of the shells from thirty years of infestation. Simonson Photo)