Steelhead trout's eating habits baffling to fisheries biologists

02/16/03

Can there be too many steelhead trout swimming in Lake Erie?

Fisheries biologists at the Fairport Harbor Fisheries Station are trying to find out. While anglers can't get enough of the big, silvery fish, there is always the risk that they might someday eat themselves out of house and home.

"We're doing a pilot study on the eating habits of steelhead trout to pinpoint just what they prefer," said the Ohio Division of Wildlife's Kevin Kayle, who has guided the steelhead trout program since its inception. "We're not at risk right now, or in the foreseeable future, of having to reduce our stockings. There is plenty of forage in Lake Erie for them."

The Michigan Department of Natural Resources trimmed its stocking schedule in 1999 after a few years of mediocre salmon and trout fishing. Alewives are the primary forage for the big game fish, and they were disappearing.

With reduced stockings, the Lake Michigan fishing improved.

"Lake Erie steelhead trout are generalists when it comes to their feeding habits," said Kayle. "The most common source of food checked last summer was the spiny water flea. Of fish species, smelt was the top food choice, followed by emerald shiners."

Trout feed on bugs when they move into the streams. While in Lake Erie, they still feed on insects, snacking on hatching mayflies and even the Asian lady beetles that littered Lake Erie last year.

In the Fairport Harbor area, steelhead trout were often easier to catch than walleyes last summer. That puzzled biologists, who wondered if walleyes were trying to compete with the more aggressive trout for the same food.

"We want to examine the diet of both species this year by checking fish caught on charter fishing boats throughout the summer," Kayle said. "By checking trout and walleyes caught on the same day from the same area, we can do a head-to-head comparison of their diets."

Walleyes may be difficult to manage, with weather during the spring spawning season determining their success. Steelhead trout are much easier to manipulate, with the ODOW rearing about 400,000 trout at its Castalia State Fish Hatchery to stock in the rivers each spring.

D'Arcy Egan