Thousands of black crappie died of oxygen depletion this spring in Jordan Lake, Lake Odessa, Michigan. Lake Odessa is the headwaters of the Coldwater River, a significant tributary of the Thornapple River. Lake residents are angry at what they perceive as mismanagement of the lake ecosystem by the Jordan Lake Board.
A meeting to discuss the problem was organized by Terry Gieger, State Representative, on Tuesday, August 29, 2000.
Many residents blame the kill on the use of chemical herbicides to kill aquatic plants that are choking the lake. It is thought that when the plants began to decompose, this removed oxygen from water that was already depleted of oxygen due to a run-off of sediments during a rainy spring. The fish suffocated due to low oxygen levels.
The Jordan Lake board entered into a management agreement with Professional Lake Management in Alto, Kent County. The company controls weed growth in inland lakes by using herbicide chemicals to kill algae and Eurasian millfoil, which tend to overgrow and choke lakes with weeds. The company applied herbicides to Jordan Lake to kill algae in the early spring, and the chemical Sonar was applied to kill Eurasian millfoil only a few days before the die-off began. Professional Lake Management insists the chemical had nothing to do with the die-off. They seem to be supported by the Jordan Lake Board; John Bush, Ionia County Drain Commissioner and board member, says that Sonar is the safest chemical there is. The DEQ issues Sonar permits only once every five to seven years.
Weed overgrowth can be due to many factors, but usually is due to excess nutrients entering lakes from resident's lawns, septic systems, and agricultural areas. Eurasian millfoil is an exotic species (not native to the United States lake ecosystems) that over-runs native aquatic plants much the way purple loosestrife does.
If the herbicide Sonar is so "safe", why does the DEQ issue a permit for its use on a specific lake only once every five to seven years?
It seems likely that the dying vegetation contributed to the oxygen depletion and the die-off of the fish. The mission of the Jordan Lake Board should not just be to allow Professional Lake Management to apply herbicides to Jordan Lake as if it were a big green lawn. The chemicals used may be deemed "safe", but if the Lake board had to drink them, would they still feel the same? No? The Tip of the Mitt Watershed Council has some bad news for them, then. These chemicals persist in drinking water wells near the lake to which they were applied (see link below). This means they persist in groundwater systems.
Both the company and the board should use this event and controversy as a wake-up call. This is an opportunity for both to learn how to do some REAL lake management. There is a great deal more to lake ecosystem management than the chemical companies would lead one to believe. There are other ways to control the overgrowth of weeds; people can actually learn not to be the cause of them. Professional Lake Management should be in the business of teaching residents their part in aquatic ecosystem management, not just in the business of controlling weeds proliferating from bad management.
The Board and Professional Lake management can encourage lake residents to create landscapes with native plants in their backyards. Once established, these landscapes can be maintained by sustainable management practices which limit the use of fertilizers, pesticides, and herbicides. Sustainable landscapes require less chemical treatment, reducing chemical inputs into the environment which have nontarget effects on the ecosystems, its plants, and its animals. Excess phosphorous and nitrogen from fertilizers can run off from the landscape into the waterways and create nutrient enrichment that encourages the growth of algae. Native plants used as buffer strips along lake margins can absorb these nutrients.
TRWG can put the lake board, residents and the management company in touch with educational resources on these topics. The information is out there, and available.
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