King empire

As alewife deaths rise, Michigan aims to increase stocking of king salmon

EMPIRE, MI – The shoreline of Sleeping Bear Dunes along Lake Michigan has become a fish graveyard.

Along the high-water mark, groups of small silvery fish carcasses pile up in the sand; a scene reminiscent of decades past when invasive prey fish, native to the Atlantic Ocean, died in such numbers that they were bulldozed away.

Michigan fisheries officials say the 2022 die-off is far from levels seen in the 1960s, but is above normal. Dead alewife beach every year, but their growing population, coupled with unusual spring weather and early migration to the lake, has led to fish kills on the coast between Muskegon and the Strait of Mackinac.

In response to growing numbers of alewife, the Michigan Department of Natural Resources (DNR) is advancing a proposal this summer to increase the number of chinook, or “king” salmon, it stocks in the lake to 1 million fish l ‘next year.

This year, the DNR stored approximately 687,000 chinooka popular sport fish that can get quite large and feasts almost exclusively on alewife as its protein of choice.

“We looked at that and agreed to go up to a million fish,” said DNR Lake Michigan basin coordinator Jay Wesley. “Now we have to consult with other states and tribes.”

MNR needs the Great Lakes Fishery Commission Lake Michigan Committee to approve the increase in inventory before it could go ahead. The DNR proposed the increase in 2020 and 2021, but the committee, which includes representatives from every state bordering the lake as well as the Chippewa-Ottawa Resources Authority tribal tribe, wanted to wait.

If approved, it would be the first major increase in Michigan’s chinook stock since the late 1990s, when 3 million fish were stocked, Wesley said. A final decision would be required by September in order to increase the egg take at the Little Manistee River weir where eggs are collected.

Because chinook are popular with anglers and fishing charters, Wesley and other fishing experts expect news of increased stocks to be welcome.

“The fishing has been tough,” said Dan O’Keefe, a fishing educator with Michigan Sea Grant. “It hasn’t been bad, but it has been more difficult in recent years.”

O’Keefe said average chinook catch rates coupled with increasing size of salmon caught – the 43-year-old record fell last summer when an Ortonville teenager rocked a 47.8-pound monster at the off Ludington – indicate that existing predatory fish have plenty of alewife to eat.

Luis R. Martinez holds the 47.86-pound, 47.5-inch Chinook salmon he caught in August 2021.

“We know we are coming out of a period of historically low alewife abundance over the past few years, which is why stocking has been reduced so much,” he said.

Great Lakes fish populations are measured by weight, and Wesley said the Lake Michigan alewife preyfish population is believed to have rebounded since 2016 to around 100 kilotons; roughly what it was in 2012 during the last mass death of comparable size.

“We seem to be at that mark today,” he said.

Gary Whelan, a fisheries biologist for more than 30 years with MNR, said alewife are very sensitive to changes in water temperature. Alewife prefer cooler waters and hang out near the lake’s thermocline, or the layer of the water column that marks a steep temperature boundary.

Lake temperatures have fluctuated dramatically (up to 10 degrees in a matter of hours) at times this spring thanks to frontal weather systems like the one that spawned a devastating May 20 tornado in Gaylord. Such weather systems can have a dramatic impact on Great Lakes water temperatures.

The fish did something strange this year too.

“For some reason they moved north much earlier than normal this year, which exposed them to temperature shock and big temperature changes,” Whelan said.

Alewife wintered in the southern half of the lake. Whelan speculates that the warm temperatures in May warmed the lake enough to trigger a northward shift, which usually occurs in June. The first death reports soon followed.

The public is encouraged to report fish kills to michigan.gov/EyesInTheField.

“We’re still hearing reports,” Whelan said, coming from Charlevoix north to Wilderness State Park along the Strait of Mackinac, and west to Beaver Island and out to Green Bay.

Mass mortality is expected to ease as the lake stratifies and temperatures stabilize this summer.

“We’ve seen a lot of unusual weather fronts and temperature changes in northern Michigan waters this spring,” Whelan said. Coupled with low food resources and spawning stress, “you add heat shock and these fish don’t tolerate it as well.”

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