Fish Kill Could Be Good for Local Lakes
April 7, 2014 — Source: Indiana Department of Natural Resources
Photo Courtesy IDNR/ Outdoor Indiana Magazine
Although thousands of gizzard shad died this winter in northern Indiana lakes, DNR biologists say the loss of the unwanted fish is a good thing.
Shad are not targeted by anglers because of their foul flavor, and they compete for habitat and food with popular sport fish. Where shad are abundant, corrective steps are often needed to control their population.
“Controlling gizzard shad numbers is one of our biggest fish management challenges,” said Jeremy Price, DNR regional fisheries supervisor.
The DNR has applied selective pesticides at some lakes to deliberately kill shad. The DNR also stocks predator fish such as muskies and walleyes at other lakes to feed on shad.
“The more we keep shad populations under control, the better off fishing is,” Price said. “So when a shad die-off occurs naturally, we see that as a positive thing.”
Gizzard shad are a silver fish that can grow up to 18 inches long. They feed on microscopic zooplankton.
Although native to northern Indiana, shad are typically found in lakes and rivers in the Eel, Kankakee, Maumee and Tippecanoe river watersheds. They do not naturally occur in lakes and rivers that drain to Lake Michigan.
“We have seen some widespread increases in shad populations in recent years throughout the region,” Price said. “That may have been due to warmer winter weather we had until this year.”
Shad are sensitive to cold water. During harsh winters, shad kills occur throughout the Midwest and as far south as Tennessee.
“Gizzard shad die-offs are one of the natural processes that go on in our lakes,” Price said. “Their death does not mean a lake is polluted.”
The dead shad also pose no threat to water quality or other fish and wildlife. They are often eaten by birds or decompose quickly.