The Iowa Department of Natural Resources (DNR) discovered 26, 3- to 5-inch gizzard shad, in East Okoboji Lake on August 11 as part of routine sampling.
“We don’t know how gizzard shad got into the lake,” said Mike Hawkins, fisheries biologist for the Iowa DNR at Spirit Lake. “It is possible that someone intentionally put them in the lake.”
This is the first time gizzard shad have been found in the Iowa Great Lakes. Gizzard shad were not sampled in West Okoboji Lake or Spirit Lake.
“The Iowa Great Lakes are at the northern edge of this species’ range,” Hawkins said. They do not tolerate long winters and are usually found in southern Iowa lakes and streams. “Mild winters the past few years may have allowed them to survive further to the north.” Click on the following paragraph to access the full story.
Gizzard shad are known to disrupt fisheries and compete with native fish like bluegill and yellow perch. “We can’t predict their impact in the Iowa Great Lakes at this point. Because we are at the northern edge of their range our winters should hold their numbers in check. Gizzard shad can reproduce in large numbers and our continued mild seasons could favor this species,” said Hawkins.