Unwanted fish returning to Lake Everett

Indiana DNR Release:

ARCOLA – Gizzard shad, the target species of a state-funded fish eradication project, are returning to a nuisance level at Lake Everett, a 43-acre lake in northwest Allen County.

According to the DNR Division of Fish and Wildlife (DFW), shad continue to pose a fish management challenge at the lake, and biologists are considering other options to reduce shad abundance.

Throughout the last decade, the number of shad increased sharply in the lake. By 2004, shad were the dominant fish captured in fish surveys. Shad made up 43 percent of the number of fish and 54 percent of the weight. By 2008, they accounted for 63 percent of the weight of fish in the lake.

Because shad, a slender, silver fish of little interest to anglers, compete for food with bluegill and other popular sport fish, overall fishing quality at Everett had declined.

To selectively reduce the number of shad, biologists applied 21 gallons of rotenone to Everett in 2008. When used in low amounts, rotenone primarily kills shad. Based on sampling last year, 90 percent of the adult shad were killed.

But the reduction was short-lived.

“The shad are back in Lake Everett,” said Jed Pearson, DFW biologist who conducted the eradication project. “We caught 93 adult shad during a recent fish survey there, and they made up nearly half of the weight of all fish.”

The shad ranged from 9 to 16 inches long.

Pearson said most of the shad entered the lake from a downstream area. A large pond containing shad is connected to Everett’s outlet, which also connects to the headwaters of the Eel River.

“We knew there was a good chance that shad could get back into Everett from these areas,” Pearson said. “To block them, we originally wanted to install a barrier at the outlet. But concerns over maintenance of the barrier and potential flooding problems ruled out that option.”

Rather than do nothing to reduce the number of shad, the DFW conducted the rotenone project to buy time to build up the lake’s predator fish population. After the treatment, 4,300 bass were restocked; however, high water levels have compounded the problem.

“We saw thousands of shad in the outlet after heavy rains in May,” Pearson said. “There was virtually nothing there to stop them from getting into the lake.”

While the DFW will not re-treat the shad with rotenone, other options being considered include raising the size limit on bass and stocking muskies to feed on shad.

“More and bigger predator fish won’t solve the shad problem,” Pearson said, “but they can at least convert some of the shad biomass into fish for fishermen.”