justnorth posted on December 19, 2007 11:14 :: 1767 Views
Fish are not affected by the parasite in Lake Winnibigoshish (Winnie) that is suspected this past fall in the die-off in scaup (bluebills). Nor are other wildlife such as loons, eagles and raccoons adversely affected by the small intestinal parasite called a trematode, according to the Minnesota Department of Natural Resources (DNR).
“We have received several reports of anglers calling Lake Winnie resorts because they were concerned about the safety of eating the fish in the lake,” said Chris Kavanaugh, DNR Grand Rapids area fisheries manager. “However, this trematode is very selective and does not affect yellow perch, walleye or other fish. Anglers can eat fish from Lake Winnie without worry of the trematode. ”
While the parasite led to the die off of nearly 7,000 scaup on Lake Winnie this fall, there was no evidence that eating the dead scaup adversely affected raccoons and eagles,” said Perry Loegering, DNR Grand Rapids area wildlife manager.
“And, most important, these trematodes are not known to be a health risk to people.”
The DNR, however, recommends that hunters not eat sick waterfowl and use standard precautions, such as wearing rubber gloves and thoroughly washing hands when cleaning waterfowl. All waterfowl should be thoroughly cooked prior to consumption.
The scaup deaths were caused by Sphaeridiotrema globulus, a small trematode less than 1 mm in length. Trematodes have a complex life history and require two intermediate hosts, such as snails, for the parasites to develop. DNR officials have documented large numbers of the banded mystery snail, Viviparus georgianus, along the western side of Lake Winnibigoshish for at least eight years. The species is native to eastern North America and has been documented in other lakes in Minnesota. However, it is still unclear if this snail is capable of serving as one of the host species for the trematode.
The threat of invasive species is very real and can have effects on many levels of the ecosystem. The DNR reminds people not to dump aquarium fish, snails, and water into the lake. These are not native species.
Anglers, hunters and others who recreate in the outdoors need to be aware of transporting non-native species. Simple precautions, such as draining all water from the boat before leaving the landing, disposing of unused minnows on shore, and cleaning all plant fragments or other materials from the boat and trailer will reduce the likelihood of transporting an unwanted pest to a new area.
DNR fisheries and wildlife staff collected live snails before freeze-up to help isolate intermediate stages of the trematode. More monitoring and testing will occur in the spring.
DNR is working with the National Wildlife Health Lab, U.S. Department of Agriculture Wildlife Services, Leech Lake Band of Ojibwe, U.S. Fish and Wildlife Service and other partners to develop a sampling plan that will begin in the spring of 2008. The research will help determine the extent of these snails and trematodes in Lake Winnibigoshish and other Minnesota lakes.
Additional information can be found at www.mndnr.gov/hunting/waterfowl/scaup.html.
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