(Connection of the Okobojis -- Community First Broadcasting Staff Photo)Okoboji, Iowa (RI) — The Iowa Department of Natural Resources says its most recent survey shows an increase in gizzard shad in the Iowa Great Lakes.
Fisheries biologist Andrew Carlson says the species have been present in the Little Sioux River drainage to the south, but until recently had not moved as far north as the lakes.
Carlson says they are found in rivers throughout the Midwest, but they are susceptible to large die-offs during cold, ice-covered winters.
Carlson says gizzard shad eat zooplankton, which other desirable species also rely on, so biologists are monitoring the population closely.
He says smaller gizzard shad can also benefit the lakes by serving as a food source for top game fish.
Carlson says the shad may have entered the Iowa Great Lakes during the 2024 flood.
The DNR has conducted shoreline surveys on Spirit Lake, East Okoboji, and West Okoboji at fixed, standardized sites every year since 1989.
