A team of contractors spent their weekend hauling thousands of dead fish carcasses from the waters of Minnesota’s Como Lake, the Minnesota Star Tribune reported on Tuesday. Located in a suburban park in St. Paul, the lake is now down about 1,000 bluegill and crappies, which died en masse as a result of low oxygen — a side effect of a rapid influx of heat.
Down south in Arizona, state wildlife officials closed public access to San Carlos Lake indefinitely after drought conditions and a nearby dam release “resulted in a major fish kill affecting approximately 100 percent of the fish population.” Across the country in Massachusetts, the Charles River was the site of a massive die-off of carp after a pre-summer heat wave baked fish exhausted from spawning.
In an interview with local station WGBH, River Science Program Manager at the Charles River Watershed Association, Marielena Lima said it was a “noticeable” fish kill for this point in the season.
“It’s such an early fish kill. Usually it happens later down in the summer when it’s really hot,” Lima said. “But we’ve been in a drought for months now, so I think it’s just kind of all these compounding effects on fish in our watershed.”
Fish kills aren’t a new phenomenon, and they aren’t all caused by extreme heat. As Britta Belden, monitoring and research division manager at the Capitol Region Watershed District explained to the Star Tribune about the Lake Como event, they aren’t even inherently alarming.
“These individual species populations do boom and bust in the lake. This is natural,” Belden said. Still, she added that hotter summer temps caused by climate change may make fish kills a more common occurrence. “The best we can do is continue to support the lake and ecosystem health,” she added.
Sure enough, recent studies have predicted that fish kills are set to skyrocket in the coming years, as the correlation between extreme heat and fish mortality becomes impossible to ignore.
And it’s worth noting that the headline-grabbing fish kills come after the second-hottest May ever recorded in human history, with global air temperatures 2.55 degrees Fahrenheit higher than the pre-industrial norm.
If leading climate scientists are to be believed, that’s only the beginning, as the coming summer of 2026 is shaping up to be one of the hottest on record, coinciding with a major oscillation in the El Niño cycle. If the Earth is a big pond, we’re all the fish.
More on extreme heat: Heat Waves Are Getting So Brutal That They Just Kill You, Full Stop