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August 9, 2011

MADISON -- The estimated 50,000 or more Wisconsin waterfowl hunters whose favorite hunting partner has four legs, a tail, and doesn't mind swimming in cold water may want to take some precautions against their friend coming down with serious illness from ingesting water containing potentially toxic blue-green algae.

"Working together with dogs is part of a long and rich tradition for many waterfowl hunters," said Kent Van Horn, DNR Migratory Game Bird Ecologist. "Sometimes, care of these furry hunting companions requires extra awareness. While not widespread, potential toxicity from blue-green algae is still a concern for waterfowl hunting dogs."

Recent cases included three Wisconsin dog deaths from blue-green algae poisoning reported in 2008, two in 2009, and thankfully none in 2010.

With about 80,000 waterfowl hunters, Wisconsin has the third highest number of waterfowl hunters in the country. About 60 percent of Wisconsin waterfowl hunters use dogs to retrieve their harvested ducks and geese.

What is commonly referred to as blue-green algae are actually cyanobacteria, microscopic organisms that are true bacteria. They are present in all lakes, marshes, ponds and ditches across Wisconsin but live unrecognized except for when the right conditions develop and the cyanobacteria grow quickly, creating "blooms" across the water surface that look like paint, thick scum, or "pea soup." When blooms occur, cyanobacteria can release toxins that can cause illness and even death in many animals ingesting them, including dogs and humans. While blooms of blue-green algae occur most frequently in summer, blooms have been observed in Wisconsin in fall and winter. During the fall waterfowl hunting season, toxic bloom conditions can develop on warm fall days or on lakes that are in fall turn over.

Cyanobacteria "bloom densities" can develop in surface waters with high concentrations of nutrients, particularly phosphorus. Blooms tend to grow when there is a lot of sunlight, the temperature is warm, the water is shallow and there is little wind. Sometimes when the wind kicks up, blue-green algae will pile up on the windward side of the lake.

Hunters should be on the lookout for the following conditions in the field: a green "pea soup" appearance, surface water blooms that are green, blue, red, or brown in color, or foamy scum layers, mats or blobs.

Hunters should adhere to the following advice of the Wisconsin Veterinary Medical Association to help protect their dog's health:

After potential exposure, watch your dog for signs of lethargy, loss of appetite, vomiting, diarrhea or even seizures. If your animal shows any of these symptoms contact your veterinarian immediately. More information on blue-green algae in Wisconsin can be found on the Blue-Green Algae In Wisconsin Waters page of the DNR website and [blue-green algae page of the Department of Health website (exit DNR).

FOR MORE INFORMATION CONTACT: Kent Van Horn, DNR Migratory Game Bird ecologist (608) 266-8841: Gina LaLiberte DNR research scientist (608) 221-5377

Last Revised: Tuesday, August 09, 2011

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