Invasive zebra mussels selectively consume good algae, not the toxin-producing one

Many Beaver Dam Lake property owners got a surprise when they removed their docks this fall. Zebra mussels have become prevalent in the lake and attached themselves in great numbers to structures in the water.

“There was talk over the last six months that there were zebra mussels in the lake,” said Bill Boettge of the Beaver Dam Lake Improvement Association.

Boettge said the appearance of the invasive species was seen as inevitable after the mussels were reported a few years ago in Fox Lake.

In May, Wisconsin Department of Natural Resources Warden Paul Nell said zebra mussels had been found in Mill Creek in 2013. The creek feeds into Beaver Dam Lake from Fox Lake.

Nell said it is common for anglers in southeastern and south central Wisconsin to move between lakes, often in the same day. The mussels have been in the Great Lakes since 1985 and eventually moved from Lake Michigan to Lake Winnebago. From there mussels were transported to Fox Lake, most likely by a boater, Nell said.

Boettge said zebera mussels appear to be most prevalent in the southern half of the lake. He said it is unknown how zebra mussels will affect the body of water.

The mussels feed by filtering microscopic plants (primarily algae), animals and debris from the water and, in spite of their size, are capable of processing almost a liter of water per day. They begin to breed at about one year old and can produce over 40,000 eggs in a reproductive cycle and up to one million in a spawning season.

The DNR lists the zebra mussel as an invasive species because of the negative impact on lakes, streams and rivers. The mussels are very prolific and their feeding method leads to greater water clarity which in turn reduces the food supply for other organisms and fish and promotes growth of aquatic plants.

Beaver Dam could use more aquatic plants, according to Boettge, but too many can inhibit the ability of sight feeding fish such as walleye and northern and can also create problems for anyone wanting to recreate on the water. The mussels can also promote the growth of blue-green-algae because they avoid this type of algae when feeding.

According to the DNR and the United States Geological Survey (USGS) there is no known way to control zebra mussels once they’ve become established.

As a precaution, BDLIA recommends that anyone entering the water wear some sort of foot protection. If a boat is on a lift, be sure to keep the lower unit out of the water to prevent colonies from blocking water intakes.

BDLIA will continue to monitor the situation and provide periodic updates to its members and the public.


Photo: Zebra mussels cover a tire that is part of a dock pulled from Beaver Dam Lake by a Edgewater Drive resident last week. The invasive species arrived in Beaver Dam Lake sometime in the last year and has quickly multiplied.

View original article at: Zebra mussels move in


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