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Burbot babies

NMU Fish Biology Lab taking part in unique project

Thornton Ritz, a graduate student in the Northern Michigan University Department of Biology, stands by the section of the NMU Fish BiologyLab where burbot eggs and hatchlings are kept. The eggs came from the Sturgeon River. (Journal photo by Christie Bleck)

MARQUETTE — It’s not the most sought after game fish, and it’s professionally managed even less. However, the burbot is an important part of the Great Lakes ecosystem, and any research probably will help people better understand this species.

A major breakthrough has taken place in the Fish Biology Lab at Northern Michigan University where the first of the burbot eggs obtained from the Sturgeon River, a Lake Superior tributary, recently hatched.

Jill Leonard, a professor in the NMU Department of Biology, said that to her knowledge, this marked the first time burbot have been hatched in a laboratory in the Great Lakes region, and NMU is one of the few places trying this anywhere.

At the forefront of the project is Thornton Ritz, a second-year graduate student in the biology department.

“Most people don’t really know much about burbot,” Ritz said. “They’re a freshwater fish that’s found throughout the world. They’re in all of the Great Lakes, and there’s very little research done on them for a number of reasons, mostly because they’re pretty elusive.”

This is a photo of a burbot larva, which is about 3 millimeters long, taken under a microscope on Wednesday at the NMU Fish Biology Lab. (Photo courtesy of Thornton Ritz)

That’s for sure. Ritz said burbot have been found in depths up to 1,000 feet in Lake Superior, so they’re hard to catch.

In the winter, though, some burbot spawn in Great Lakes tributaries while others spawn in the shallows or in reefs, he said.

“So, the wintertime is the time to get them,” Ritz said. “We worked with some river-netters in the Sturgeon River out of Baraga and Pelkie, and they do a traditional Finnish, sort of trap net, to catch these fish.

“They’ve been doing it for years. This is all for subsistence. They dole it out to the community. There’s no money involved.”

NMU finally got the fish it needed: a female with “ready” eggs that could be fertilized easily, which he acknowledged had been a problem in the past.

Ritz has fertilized two burbot families so far, with eggs incubating in the lab for about 30 days.

This past Saturday — day 30 — they began hatching.

Leonard said people typically fish for burbot while ice fishing.

“I think people find them to be interesting game fish,” Leonard said. “They’re just sort of not ‘top of the list’ because you’ve got to be pretty hardy to be an ice fisherman to go out after them, and they usually fish at night for burbot, so it’s sort of like a double-hardy ice fisherman.”

Leonard said burbot are considered a game fish, though, because there’s a small recreational fishery for them as well as a net fishery.

A look at a burbot, or even a picture of one, might turn a few heads.

“A lot of times people think they’re kind of eel-like, but they have nothing to do with eels,” Leonard said. “They are long, kind of dark-colored. Usually their bellies are a little bit lighter color. A little bit mottled.

“And they have the cutest little barbel on their chin, so they’re very different.”

According to Michigan State University Extension, a burbot also is known as lawyer, eelpout, ling or freshwater cod, and is the only freshwater member of the cod family.

Keep in mind the cod is an ocean fish.

“They kind of act like a marine fish in some ways, and from an eating perspective, they taste a lot like cod, which for coastal folks, that’s like the classic fish that you find in fish chowder or something like that,” Leonard said.

Ritz said an Idaho hatchery, which rears burbot, is restocking the species to help a wild population that’s been decimated by a river dam. Last summer, NMU got samples of the hatchery’s larval fish throughout their development.

He photographs the fish under the microscope, measures them and looks at body shape.

“How does their body shape as they develop?” Ritz said. “They absorb this yolk sac. They get bigger. Certain aspects of their body change at different rates.”

He also has examined wild Great Lakes burbot larvae.

However, the lab now has its own larvae he will study — and that involves a little martyrdom on the burbot’s part.

“Hopefully, if we have enough, when they get big they’ll be used for other studies in our lab,” Ritz said. “Unfortunately, as I go along, I have to sample them and I have to kill them because that’s just part of it.”

However, that also gives NMU a great sampling and staging set as they develop.

Ritz said that means students can learn how the larval fish develop in their first 10 weeks.

“It gets more use than just my thesis,” he said. “It’ll be something that the university and something that Dr. Leonard can use for years to come.”

Leonard believes burbot research has value.

“This is a fish that is a top-level predator in the Great Lakes,” Leonard said. “There is interest in catching it for food purposes. There are cultural implications to it, so it’s important to some of the tribes, and it’s really probably quite ecologically important because it’s that top-level predator that is needed.”

She said its diet includes smelt, perch and round gobies, and since these gobies are invasive, the burbot could help with controlling that species.

The burbot also is picky about temperature, she said, so the fish is considered by some to be a good indicator species for climate change.

“It’s a player in a lot of different stories, but it’s one that we know very little about, and particularly, we know very little about younger life stages and also in the Great Lakes,” Leonard said.