(Spirit Lake)--The Iowa Department of Natural Resources has documented an increase in gizzard shad across the Iowa Great Lakes. DNR Fisheries Biologist Andrew Carlson with the Spirit Lake Fish Hatchery says gizzard shad are native to many rivers in the Midwest and are moving north and northwest in their range.
Carlson says the exact ecological impacts of gizzard shad in the Iowa Great Lakes remain unknown.
Research on gizzard shad at the northern edge of their distribution shows that low winter temperatures frequently trigger high winter mortality.
Carlson says boaters and anglers can do their part to minimize the spread of gizzard shad.
Iowa DNR Fisheries teams will continue regular fisheries sampling across the Iowa Great Lakes to track dynamics of forage fish, game fish, and other species.
