OAKDALE, Minn. — The customers weren't biting as often as they usually would at Josh Stevenson's shop in Oakdale, Blue Ribbon Bait and Tackle.
"Business is definitely slower during the heatwave," said Stevenson. "I mean, it's just uncomfortable to be outside."
It's not just anglers who feel the heat.
"When the temperature increases, it also increases the water temperature," said Simon Tye, a wildlife biology researcher at the University of Arkansas. "And that can lead to direct thermal stress to cold water fish species."
When fish are already in hot water, the stress of getting reeled in can push them over the edge, and they could die.
"Those cool water fish like walleye and muskie, when you get water temperatures in the upper 70s, that's where they can really start to get stressed out when they're being reeled in," said Brian Nerbonne, the Minnesota DNR Regional Fisheries Manager. "They're extending a lot of energy, and it takes a lot longer for them to recover."
Nerbonne said that in warmer surface-level temperatures with already depleted oxygen levels, fish can overexert themselves.
Depending on how long they stay above the surface, they can die after release.
"We’re hearing about lakes being over 80 degrees at the surface in the sort of southern half of Minnesota," said Nerbonne. "That's getting pretty warm, even on some of our bigger lakes."
Stevenson is also a fishing guide. He avoided catching walleye and muskie this week.
"If I can't guide for a few days and I lose a little bit of money that's okay, because if the muskies or the bass are still going the week after, that's worth a small sacrifice," Stevenson said.
Stevenson also said anglers should have their release tools at the ready if they do choose to go out and catch vulnerable species.
"It should be about a 10-second deal," he said.
He added that if anglers are planning on taking their catch home, it shouldn't matter.
Scientists suspect there will be more frequent heat waves for anglers to deal with in the future.
"I think the likelihood of having these warm spells like we just had the past week is going to be higher as we go forward," said Nerbonne. "We're starting to see some warmer summers, although that's not something that we've really seen a strong signal for yet if you look at the climate data, it's certainly something that's predicted going forward."
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