May 13, 2004

State fisheries officials today reminded anglers on Lake St. Clair to report observations of sick or dead muskie that appear to suffer Piscirickettsia, commonly called “muskie pox.”

The bacterial disease, which does not affect humans, was first identified by Department of Natural Resources and Michigan State University scientists in early 2002. It is similar to a bacteria that has caused widespread death among various trout and salmon species in Chile, Norway, Ireland and Canada, but further investigation indicates that the strain found in Lake St. Clair muskellunge is a different bacteria.

Fish exhibiting visible signs of muskie pox have red skin rashes and sunken eyes. Fisheries experts researched the bacteria last summer, both in the field and in the laboratory. Fish captured and tested at various locations throughout the U.S. side of Lake St. Clair all showed some level of infection, indicating the bacteria exists throughout the lake. However, laboratory researchers noticed Piscirickettsia is very sensitive to antibiotics, indicating that infected fish can be treated.

Research in 2004 will focus on developing a management strategy to control the disease and slow its spread. Fish sampling will focus on muskies as well as likely prey species, to determine what other species in the lake may be infected by or act as a reservoir for this bacteria. Researchers also will continue to monitor the rate of external symptoms in and the location of infected Lake St. Clair muskies.

“We need the help of the angling community, to report what they see on the lake and to take some simple steps to prevent spreading this disease to other waters,” said DNR Fisheries Biologist Michael Thomas.

Anglers who observe sick or dead muskies with visible infection signs are asked to contact DNR to report the estimated size of the fish and the GPS location.

To minimize the chance of spreading the infection, anglers are encouraged to clean their baits, landing nets, and boat decks with a solution of dilute household bleach (one-quarter cup per gallon of water) followed by thorough rinsing in water after landing muskies and after each fishing trip.

To report infected fish or for more information on Piscirickettsia, contact Michael Thomas at the DNR Lake St. Clair Fisheries Research Station, 586-465-4771, or Email [email protected].

Michigan DNR