Lake Superior Herring Thriving: A Phenomenal Comeback

An Unprecedented Year for Herring in Lake Superior

In the vast expanse of Lake Superior, a remarkable resurgence is taking place. Herring, vital members of the lake’s intricate food web, have defied decades of dwindling numbers, marking a historic milestone in their revival. As we explore the reasons behind this resurgence, one thing becomes clear: it might be connected to the ever-changing climate.

Herring (Image source: Twitter)

A Herring Boom of Unprecedented Magnitude

The massive influx of herring in Lake Superior is nothing short of astounding. These small yet significant fish seem to have not only persevered but thrived, particularly in their first year of life. This is a crucial developmental stage for them and signals a promising shift in the ecosystem of the world’s second-largest freshwater lake.

Cory Goldsworthy, the Lake Superior area supervisor with the Minnesota Department of Natural Resources, marvels at the sheer scale of this phenomenon. He notes, “We’ve never seen this amount of biomass, this amount of energy coming into Lake Superior. The scale of it is just phenomenal.”

The Mysterious Rebound

Scientists are facing a mystery with the resurgence of herring, also known as cisco. Overfishing, invasive species and the impact of climate change have collectively contributed to the decline of these slender, silvery fish, making it rare for them to reach adulthood at 14 inches. However, a relatively cold spring followed by a warmer summer in the previous year may provide some insight into the dramatic increase.

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In 2022, the Lake Superior region experienced near-record cold temperatures in the spring, followed by a warm summer. These conditions proved beneficial for zooplankton, the primary food source for herring, as they flourished while herring eggs developed. The result was a feeding bonanza once the fish hatched. Goldsworthy suggests, “It seems like that occurred perfectly in 2022.”

A Promising Future

Fast forward to 2023, and the majority of these herring have not only survived their first year but are on their way to adulthood, with the potential to live up to 40 years. Lake-wide surveys conducted by the USGS and Minnesota DNR have revealed substantial numbers of herring throughout the lake this summer and fall.

Goldsworthy highlights the astonishing transformation, “There have been years when the USGS does this whole circumnavigation of Lake Superior bottom trawling, and they don’t catch a single age one cisco. This year, they’ve caught in one trawl more age one cisco than in previous entire assessments. The scale of production is phenomenal.”

The Significance of Herring

Herring are not only cherished for their meat and eggs, which can be turned into caviar, but they also play a crucial role in the food chain. They serve as prey for larger lake fish like trout, walleye, and steelhead. An increase in the herring population can lead to healthier populations of these fish, benefiting both commercial and recreational fishing.

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From an ecosystem perspective, cisco act as an energy transfer system. As adult herring swim and feed in open waters away from the shoreline, they capture energy, which they bring back to the shore. This energy sustains the fish communities that inhabit the area. Given the potentially long lifespan of herring, this resurgence promises to fortify the ecosystem for years to come.


The unexpected resurgence of herring in Lake Superior is a testament to the resilience of nature. While the precise reasons for this remarkable turnaround remain a subject of scientific inquiry, it is evident that favorable climate conditions have played a pivotal role. This resurgence promises to reshape the ecosystem of Lake Superior, benefiting not only the herring but also the larger fish species and the fishing industry.


1. Why are herring crucial to Lake Superior’s ecosystem?

Herring play a vital role in Lake Superior’s food web by serving as prey for larger fish, which, in turn, helps maintain the balance of the ecosystem.

2. How did climate conditions contribute to the herring resurgence?

A relatively cold spring followed by a warm summer in the previous year created favorable conditions for herring, allowing their population to thrive.

3. What is the significance of herring in commercial and recreational fishing?

The increase in herring populations benefits both commercial and recreational fishing, as it leads to healthier populations of larger fish species.

4. How long can herring live, and what is their potential impact on the ecosystem?

Herring can live up to 40 years, and their resurgence promises to bolster the Lake Superior ecosystem for years to come.

5. How does Herring’s role as an “energy transfer system” benefit the ecosystem?

As herring capture energy in open waters and bring it back to the shore, they contribute to sustaining fish communities along the shoreline, ensuring a healthier ecosystem.

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