Viral hemorrhagic septicemia was detected in yellow perch, a popular sport fish, a week after being found in the carcasses of round gobies washed up in South Milwaukee, The Milwaukee Journal Sentinel reports. The disease, first recorded in the Great Lakes three years ago, is found in many species of freshwater fish but is not harmful to humans.

Randy Schumacher, a regional fisheries supervisor with the Department of Natural Resources, said anglers should be careful not to move fish or water between lakes to help prevent the disease from spreading.

The yellow perch population in Lake Michigan collapsed in the 1980s. Commercial fishing of the species remains closed, and catch limits for sports anglers have been cut.

The disease, which causes a weakening of blood vessels, was discovered in yellow perch during the annual survey before the season opens.