Not enough alewives to support Lake Michigan salmon

Spiel · July 20, 2008

Not enough alewives to support Lake Michigan salmon

July 17, 2008

Lake Michigan hasn't experienced the dramatic decline in salmon that Lake Huron has seen, but there are "certainly a few warning signs that are going on," said Steve Hogler, Wisconsin Department of Natural Resources fisheries biologist serving Manitowoc County.

The problem in Lake Huron is there were more salmon than the lake could support because of a combination of stocking and natural reproduction along with a decrease in the small fish the salmon ate, which was a result of invasive mussels, Hogler said.

A similar situation is occurring in Lake Michigan, Hogler said. The lake is seeing higher numbers of salmon and trout than it can support. The DNR is concentrating its studies on Chinook salmon.

"You can only feed so many fish given what the forage levels are," Hogler said.

Salmon and trout in Lake Michigan eat alewives, Hogler said, and those small baitfish are declining.

However, Capt. Keith Heberlein of Willie Bee Charters in Two Rivers said there is a large baitfish population in the Manitowoc-Two Rivers area of Lake Michigan.

"We're one of the hot spots for the bait fish," he said.

Capt. Scott Langman of Bald Beaver Charters in Two Rivers said while the number of bait fish was down in recent years, it has increased this year. Fish locators are showing large schools of baitfish, and when the salmon are caught, "their bellies are full," he said.

That's different than elsewhere on the lake, where Hogler said the salmon have emptier stomachs than in the past and some of their fat has been replaced with water.

Along with alewives declining in Lake Michigan, some species of salmon and trout are reproducing naturally, something that wasn't expected years ago when stocking began. Chinook salmon, in particular, are reproducing at such a high rate that about half of the Chinook in Lake Michigan are naturally reproduced.

The effect of the changes is being seen as Chinook salmon caught in Lake Michigan are becoming smaller, Hogler said.

A few years ago, a 4-year-old salmon weighed between 20 and 30 pounds, said Capt. Chad Scheinoha of Chinook Express Sport Fishing Charters in Manitowoc, but now the average is between 14 and 20 pounds.

Heberlein said he had been seeing smaller fish for the past three years, but "this year we're actually seeing larger fish."

In general, though, the salmon are smaller, Hogler said.

He said the number of Chinook salmon in Lake Michigan has remained "fairly constant" over the past years as the DNR attempts to control the population by reducing stocking.

The Wisconsin DNR as well as other states that are responsible for Lake Michigan began a Chinook salmon stocking reduction in the late 1990s, Hogler said. In the most recent reduction, the number of Chinook salmon stocked on the Wisconsin side of the lake dropped from 1.4 million in 2005 to 1.1 million in 2006.

Langman said he hopes the stocking reduction is happening soon enough, but they will just have to wait and see what happens in the coming years.

It would be devastating to the local economy for charter fishing businesses to close, he said.

"Hopefully some of the lessons learned on Lake Huron can be applied to this lake," Langman said.