New appreciation for a Minnesota fish long considered junk

Researcher Alec Lackmann lifts a bigmouth buffalo fish
Researcher Alec Lackmann lifts a bigmouth buffalo fish that was shot by bowfisher Vern Bachmann on Wednesday on Crystal Lake near Dunvilla, Minn.
Dan Gunderson | MPR News

It's dark — can't-see-your-hand-in-front-of-your-face dark — as a fishing boat slowly makes its way along the shore of Crystal Lake, about 20 minutes south of Detroit Lakes, Minn.

Vern Bachmann stands on a platform at the front of the boat, poised to shoot a bow and arrow. He can see fish in the lake thanks to powerful floodlights near the waterline. He points out walleye and northern pike. Those game fish are off-limits to bowfishers. That's fine with him. He's after species like common carp, and Bachmann's favorite prey, bigmouth buffalo.

"They're more challenging," Bachmann said. "They fight harder."

"Here's one."

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Bachmann looses the arrow, which splashes through the surface of the lake. "Got him." Then, he drags the thrashing fish into the boat.

"That's a big fish. Geez."

It's a female bigmouth buffalo, looking a bit like a monster goldfish, and nearly as long as Bachmann's leg. Freshwater fish researcher Alec Lackmann weighs her in at 28 pounds.

Researcher Alec Lackmann tags a fish shot by bow fisher Vern Bachmann.
Researcher Alec Lackmann tags a fish shot by bowfisher Vern Bachmann.
Dan Gunderson | MPR News

"This one's probably around 85 to 90 years old," Lackmann estimates.

This bigmouth buffalo has been around since the Great Depression. And she's far from the oldest of the bunch. Lackmann recently published pioneering research proving these fish live more than a century, not just 30 years as previously thought.

"Notice here on her scales how she's starting to lose her color? Because she's dying basically and slowly losing blood pressure and everything," Lackmann said as he examined the fish.

He hates to see these old fish dying. He said in this part of the state, the evidence shows most of the bigmouth buffalo are around 80 years old.

"The 1920s and 1930s were a boom period; 80 to 90 percent of the fish in this watershed are that old," said Lackmann.

The reason for that advanced age is something of a mystery. The bigmouth buffalo does reproduce in some large rivers in Minnesota. Lackmann isn't sure why he hasn't found younger fish around here. He said it could be that dams, built in the 1930s and 1940s, prevented the fish from spawning. He knows these old fish can reproduce.

"We've reared progeny from a fish over 100 years old and a male over 90," he said.

Bow fisher Vern Bachmann and researcher Alec Lackmann.
Bowfisher Vern Bachmann and researcher Alec Lackmann look at a photo on a phone while night fishing on Wednesday on Crystal Lake in Otter Tail County.
Dan Gunderson | MPR News

The bigmouth buffalo doesn't age like many species, Lackmann said. They remain healthy and strong even into their 90s.

"It's one of the most exceptional freshwater fish species in the world — one of the longest-lived vertebrates in the world, and we could learn a lot from a medical standpoint if only we can have the opportunity to study them and learn more about them," he said.

But Lackmann said the bigmouth buffalo's exceptional qualities have gone unappreciated.

"They're basically a species that's been neglected over the past century because they got misconstrued and misclassified as a carp over time," he said. "They superficially look like a carp; they're big-bodied; they have huge scales; they just look kind of similar, but actually they're not a carp."

They're filter feeders, eating tiny plankton in the water. And in another interesting twist, Lackmann said he discovered they eat veligers, baby zebra mussels, a major and problematic invasive species in Minnesota. He hasn't published that finding yet, though.

Lackmann works with bowfishers, because it's a good way to study fish specimens that would otherwise be discarded. But he argues this fish deserves a bit more respect, and perhaps some protection.

Researcher Alec Lackmann takes notes on each fish killed.
Researcher Alec Lackmann takes notes on each fish killed. Lackmann works with bowfishers so he can study the fish they would normally discard.
Dan Gunderson | MPR News

Vern Bachmann is starting to think that way, too, after fishing with Lackmann on board.

"It makes you feel kind of bad for shooting fish that's older than your dad and, you know, just dumping them in the ground," he said.

Bowfishing has been growing in popularity since a 2009 law allowed night fishing. There are no limits on how many fish a bowfisher can kill. And Bachmann's hauls can be huge.

"If I get 30 to 40 fish, that's a pretty good night," he said.

It's impossible to know how many of these fish are being killed. No one tracks the number of bowfishers or how many fish they take. Bachmann said hundreds of fish can be killed in a single day at tournaments.

He said in the past five years, he's noticed a decline in the number of bigmouth buffalo on lakes where he fishes.

"This is definitely my favorite thing to do," he said. "I respect all the fish I catch. I don't want to eliminate something I'm having fun doing five to 10 years down the road either. It's not like they're hurting the lakes. So, why are we just basically allowed to go shoot them and throw them in the swamp?"

Bachmann actually buries the fish he catches, which complies with a state law requiring proper disposal of the fish.

Setting bag limits on fish species is up to the Minnesota Department of Natural Resources. There are no limits on a species considered "rough fish" to encourage removal of those fish from lakes.

Taking of bigmouth buffalo is unregulated in 19 of the 22 states where they are native.

When Lackmann first presented his data to fisheries experts, some were very skeptical of his methods. So, he had the fish ages confirmed using radiocarbon dating, proving beyond a doubt the fish ages are accurate.

DNR officials have reviewed Lackmann's research and he's presented his data to a number of agency fisheries experts.

"It definitely raises a cautionary flag," said Charles Anderson, a fisheries scientist with the DNR. He said the bigmouth buffalo research is prompting a lot of discussion within the agency.

"It means that in some areas it may be necessary to take some steps to protect populations — like old growth forests, you can't clear cut them," Anderson said.

But Anderson said the DNR has no population data on the bigmouth buffalo, so first, they need to find a way to count the fish and understand where the population might be at risk from unregulated fishing.

Researcher Alec Lackmann removes an otolith from a fish head.
Researcher Alec Lackmann removes an otolith from a fish head during a night fishing excursion on Wednesday on Crystal Lake. The calcium structure that helps fish hear grows annual rings like a tree, allowing accurate aging of the fish species.
Dan Gunderson | MPR News

That process could take several years.

Back at Crystal Lake, it's about 2 in the morning, and Alec Lackmann is on shore, cutting the heads off the dead fish.

He then delicately uses a forceps to remove small calcium deposits called otoliths from each fish's inner ear.

"They help sense orientation and vibration in the water," he said. "And the unique thing about them is that they grow continuously throughout the entire fish's life, whereas all other structures stop growing at a certain age."

By inspecting a cross section of the otolith under a microscope, Lackmann can count annual rings to determine a fish's age — just like a tree.

It turns out that 28-pound female killed earlier that night was 95 years old, and another fish was 110.

Lackmann plans to continue studying this mostly ignored native of Minnesota waters and working to win the respect he thinks the bigmouth buffalo deserves.

He thinks it's unfortunate these unique fish lack the stature and protection from overfishing that game fish have.

"Lumping them together with invasives and calling them all rough fish," Lackmann says, "then people start associating invasive carp with these other native fish that actually evolved here with the walleyes, with the northern pike and all the other highly sought-after game fish."