Wise, Chris, Bill Sloey and Craig Roesler
Parasite Found in Plum Lake
Our Lakes, Vol. 1, #3, Fall, 2009, p. 3
Lakes Committee for the Town of Plum Lake
Original Date

Re: Parasite of rusty crayfish.

Authors are listed as follows: "This article is based on phone and email exchanges by Chris Wise and Bill Sloey of the Lakes Committee for the Town of Plum Lake, and Craig Roesler from the DNR, Haywood Office.

  • Bookwood Historical Collection, Star Lake

The Lakes Committee has been informed that a parasite which affects the liver of rusty crayfish has been found in rusty crayfish taken from Plum Lake. The parasite was first found in Wisconsin in the Eau Claire Chain of lakes in Bayfield County. Craig Roesler of the DNR stated that there is a good correlation between where the parasite is found and where rusties are declining. The parasite, of the genus Microphallus, no species name has yet been assigned, is present in most lakes where the populations of rusties have declined or where rusties are present but have never become abundant. It is not present in most lakes with high-density rusty populations. It is fairly certain that the parasite affects native crayfish, but the evidence is good that rusties are more prone to it than are the native species.

Craig tells us that Microphallus is usually a three-stage parasite. It starts in snails, moves to crayfish and ends up in the final host that feeds on crayfish. In the southern United States, birds and mammals commonly host many Microphallus species. Fish and turtles have also been identified as hosts. Some species of Microphallus infect a wide range of final hosts, others may infect only one. Fish may be the final host of our species.

Craig plans to examine fish samples to see what specie(s) are final hosts. We will keep in touch with Craig to learn about what he finds.