Interconnectedness:
Something is Fishy in Upper Clam Lake!
Up until 2005, Upper Clam Lake was one of Wisconsin’s best manoomin (wild rice) lakes. It supported up to 300 acres of lush rice and yielded approximately 3000 pounds of rice per year. By 2006, there was no reported harvest of rice from the lake. Aerial images taken in 2010 showed that only 60 acres of sparse wild rice were left. The wild rice had all but disappeared!
What happened? Could climate change be a cause?
Let’s take a closer look. Upper Clam Lake supports a population of bluegill, other panfish and game fish, along with non-local (invasive) carp. Carp are vegetarians and eat aquatic plants, including wild rice. Bluegills and other panfish eat carp eggs and normally help keep the carp population in balance. Like carp, bluegills and other panfish, are warm water fish and can survive in lakes with warming temperatures.
In 2005, biologists discovered that the carp population exploded in Upper Clam Lake, at the same time the population of bluegills and other panfish died off. This left the carp with no natural controls on their population. Carp numbers exploded. Some researchers suspect that a
The suffocation of fish due to low dissolved oxygen levels in lakes during the winter
winterkill
in 2007 could have caused a massive die off of bluegills. The mystery is that no
The suffocation of fish due to low dissolved oxygen levels in lakes during the winter
winterkills
have been reported in Upper Clam Lake.
Without the bluegills to keep their numbers in check, the carp population in Upper Clam Lake is increasing. They are eating up the wild rice beds. Researchers discovered that very few manoomin seeds now remain in the lake bottom, so the rice cannot re-establish itself.
Because carp eat so much vegetation, they may also reduce the hiding places young bluegills need to survive, further reducing the chance for the bluegills to recover.
Today Upper Clam Lake has little to no wild rice. This lake demonstrates how natural resources are interconnected. What happens to one resource, affects the sustainability of other resources.
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