Fishing for answers
CLARA CITY -- Decades ago anglers worked the Yellow Medicine River and Hawk Creek hard.
They prized the Yellow Medicine River for its smallmouth bass and Hawk Creek for its walleye and northern pike.
But not until this summer have scientists worked the two streams as hard as anglers once did.
The scientists are going after fish too.
"It will give us an overall picture of what's going on,'' said Bryan Spindler, a fish biologist with the Minnesota Pollution Control Agency.
Spindler and Matthew Mitchell, a summer intern, were sorting through buckets of minnows, chubs and suckers as he spoke July 28 on Hawk Creek just north of Clara City. Earlier that morning, Spindler and his crew had electro-shocked a roughly a 500-yard long reach of the waterway.
They had stunned and collected the silver-colored fish that were now darting around in the buckets and flashing in the sun like fireflies caught in giant jars. Their job was to identify by species, measure and weigh each fish.
A few fish will also be sent to a laboratory where their flesh will be analyzed for the presence of mercury and other chemical contaminants.
As Spindler and Mitchell dealt with the squirming fish, three other crew members returned to the water in chest waders. They strode against the current with measuring equipment and notebooks. Step-by-step, the three jotted down what they found underfoot, noting whether they sloshed over sand, gravel, cobble-sized rocks or muck bottom in the hip to chest-deep water.
Chris Butterfield, a fish biologist, was also keen to jot down the type of habitat for fish and other aquatic life that was found in this channelized portion of the stream.
Sometime later, their foot steps will be retraced by another crew with a different objective. They will scoop up the bottom muck, sand and gravel to capture the aquatic or macro-invertebrates so they can be shipped to a laboratory, where they will be identified and counted.
It's a process that the crews are repeating on 132 different reaches of the two waterways this summer.
It's detailed work that is all about putting the many pieces of a puzzle together, according to Spindler. It will take a year for all of the laboratory results to be known and the data assembled and analyzed.
When it is, the MPCA will have completed a thorough Index of Biological Integrity of the two tributaries of the upper Minnesota River.
The assessment of the two waterways will tell us the truth about the water quality of each, and help us track whether we are going forward or backward in cleaning them up.
Neither of the waterways is what they were when anglers once frequented them. The upper portion of Hawk Creek was channelized in the 1950's. Both streams carry excessive nutrients, sediment and undesired bacteria as the result of human activities in their watersheds.
The Hawk Creek and the Yellow Medicine River Watershed Projects are charged with the on-going monitoring of these streams. They regularly collect water samples from them.
The monitoring is like a blood check up at the doctor's office. The water chemistry helps us identify problems and target clean up efforts in the watershed.
But water chemistry alone doesn't reveal all of the secrets of the waterways.
Fish and macro-invertebrates keep no secrets. Their presence- or lack of - give scientists a very clear picture of the health of any given waterway, explained Spindler.
There are 92,000 miles of rivers and streams in Minnesota. Each year, the MPCA takes on the challenge of conducting a thorough biological integrity study like this on waterways in portions of six major watersheds. This year's focus includes Hawk Creek and the Yellow Medicine River as part of an analysis of the Minnesota River south of Granite Falls. MPCA crews are also working in portions of waterways in the Big Fork, Bois des Sioux, Crow Wing, Mississippi in the Twin Cities and Mississippi in the Winona and Whitewater River basins.
Spindler admits the work can be difficult. The days on the water can be long, the bugs ferocious. Not too infrequently, the catch can be like the one north of Clara City. With the exception of one small and sluggish northern pike, and a few redhorse suckers, they stunned mainly forage fish that are relatively tolerant of pollution.
You have to keep focused on the bigger picture, said Spindler. When all the information is put together, it will help us identify areas in need of protection, and those in need of help.
Use the information wisely, and it can move us closer to the day when anglers will again find these waterways worth the working.