Divers found 10 zebra mussels in Christmas Lake this week, just one month after a new 3-step treatment appeared to rid the Shorewood, Minn. lake of the invasive species. In April the Minnesota Department of Natural Resources was "encouraged" by the apparent lack of zebra mussels in Christmas Lake, but this latest discovery is certainly a setback in what looked like a promising treatment option.
The 10 zebra mussels were removed from the lake, and monitoring will be ongoing. The DNR is now considering whether any further response is feasible or necessary.
"The follow-up searches suggest that the treatment in the Christmas Lake public access area was effective in eliminating mussels from the area," said Keegan Lund, DNR aquatic invasive species specialist. "Unfortunately, we found zebra mussels outside the treatment area. These zebra mussels have probably been attached to native mussels in the lake since last summer or fall."
Step 1: Zequanox (a natural substance highly selective to zebra mussels) was added to Christmas Lake in September.
Step 2: A copper treatment of EarthTec QZ was added in October and November.
Step 3: 1,000 pounds of potash was dumped under the ice near the boat launch in December. Potash is a potassium compound used in agriculture. This was only the third time potash was used for zebra mussel control in the United States.
The zebra mussel problem
Female zebra mussels can produce up to a half million eggs per year. The problem spreads when mussels attach to boats and are then transferred to other to clean lakes. More than 700 lakes in Minnesota are affected by zebra mussels, including some big metro lakes like White Bear Lake and Lake Waconia.
Be part of the solution
Clean your boats and trailers
Drain your boats and live wells
Dispose of your unused bait
Follow the legally-required 21-day drying period before transporting your dock material or related equipment to another lake