Duluth, Minn. – It’s a good time to be a Lake Superior angler.
Last year, DNR fisheries biologists in Minnesota found huge numbers of year-old cisco, or lake herring, in their survey nets. It turned out that yes historic class of 2022 for a forage fish that serves as the base of the fish food chain in Lake Superior.
Lake trout, Chinook and coho salmon, steelhead and even walleye have taken advantage of the herring boom, say government officials, charter boat captains and others, and are getting bigger and fatter. Fishing over the past two years has been steady and mostly good, even though the bellies of many trout and salmon have been full of the now bountiful prey species.
If these same herring survive and thrive over the next two years, the region’s commercial fish market – and North Shore restaurants – will be able to offer tasty fish desirable for its fillets and eggs that can be made into caviar for many years to come.
“The public doesn’t hear much about Lake Superior,” said Cory Goldsworthy, Lake Superior fisheries supervisor for the Minnesota DNR. “There’s not much going on. It’s cold, deep (lake) and not as productive as Lake Michigan. However, this is an unprecedented phenomenon that we will probably not see in our lifetime. It’s extremely exciting.”
In fact, Goldsworthy said, thanks to Cisco’s 2022 recruiting explosion, Lake Superior is in “unprecedented territory” on many fronts.
“I have heard reports of anglers catching larger Chinook in Lake Superior than in Lake Michigan, which is unprecedented,” he said. “Last year we broke the state record for coho salmon three times, which is unprecedented.”
Goldsworthy also said DNR survey crews have caught more than 100 2-plus-year-old cisco juveniles this year using small-mesh lake trout survey equipment. “In a ‘normal’ year we reach zero,” he said.
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The history of herring
According to Goldsworthy, there has been a history of overfishing of Lake Superior herring, particularly during much of the 20th century.
As a result, herring stocks have plummeted. However, tighter regulations on commercial fishing (including closed seasons in the fall) spurred a resurgence that began in the 1970s.
Herring are a species that tends to grow or fall quickly and needs perfect conditions to successfully hatch eggs and breed. First, Goldsworthy said the water had to be “icy.” Secondly, the water must be wealthy in zooplankton for the adolescent herring to grow and survive.
“Cisco can live in Lake Superior for up to 40 years,” Goldsworthy said, adding that lake trout are their main predators. “But for the eggs to hatch, the conditions have to be right.”
According to Goldsworthy, 1984 was the best herring recruitment year on record in Lake Superior, which covers more than 20 million acres (about 32,000 square miles and more than 8 million hectares). It was then that researchers from the US Geological Survey – which conducts the annual spring inventory – estimated that there were 748 adolescent herrings per hectare.
Many vintages of herring are “bust”. The last notable year class occurred in 2003, when an estimated 175 juvenile herring per acre made it to the year mark. In 2022, the estimated number of herrings per hectare increased to 1,019.
“This recent boom is about 20% larger than the 1984 record.” Goldsworthy said. “We saw an almost immediate positive impact on the growth of non-native steelhead and salmon species. This is a once-in-a-career or once-in-a-lifetime event, so it’s tough to say what the final results will be, but everything looks positive at this stage.
Noticeably larger fish
Capt. Jordan Korzenowski agrees. He’s co-owner of FishNorthMN in Duluth and has been guiding anglers on Lake Superior for eight years, approximately from May to early October each year, and has been fishing on the lake for twenty years. He said the influx of cisco fish has not only provided his customers with excellent fishing, the size structure of fish – from lake trout to coho salmon to walleye – has also increased noticeably.
“The light went out,” Korzenowski said of the fishing. “Obviously we had some slower periods. But we see a large number of large-sized fish. Historically, the July bite is usually tough. But for the last two years we have been fishing all over the world. It was really good.”
Although the state record for coho salmon has been broken three times in the last year, Korzenowski said he wouldn’t be surprised if another species of salmon broke the state record – an opinion shared by Goldsworthy and other guides.
“I wouldn’t be shocked at all if a record king (Chinook) salmon was caught this August,” Korzenowski said. The state record is 33 pounds 4 ounces.
Goldsworthy, a self-described Lake Superior data geek, said that after about two decades of impoverished herring survival, he’s not sure he’ll ever see a decent vintage, let alone a historic one.
It turned out that the lake was no longer able to support enormous numbers of herring. Invasive species have disrupted parts of the food chain, he said. Lake Superior freezes less – which he thinks is probably due to the climate – and storms in spring and fall are more intense.
“I have to admit I was concerned,” Goldsworthy said. “It’s great to see this amount of food in Lake Superior now and to see the predatory fish responding as they did before.”
How long will it take?
But the herring-gorging sport fish of 2022 can’t last forever.
“By this winter, I anticipate that most 2-year-old cisco will be too large to be eaten by walleye, steelhead, coho, Chinook and small lake trout,” he said. “There may be enough slow-growing smaller ciscoes to keep this food festival going for another year, but we’ll see.”
Goldsworthy said he hopes that in two years, when Class of 2022 lake herring grows to about 14 inches or larger, ice anglers near Duluth will have the opportunity to catch them. However, it all depends on local ice conditions.
“I’d really like to see it, but it’s very rare that we have stable ice conditions on nearby Lake Superior. It happens probably once a decade,” Goldsworthy said. “The last time this happened was in 2014 during the polar vortex.”
Editor’s Note: The Minnesota DNR continues to study predators in Lake Superior for at least the next year – and anglers can support. The purpose of the study is to measure the dietary composition of predatory fish in Minnesota lake waters. More information on submitting samples can be found in the article https://minnesotasteelheader.com/projects/ppp
