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Rebirth of Lake Sturgeon: Freshwater Species of the Week

At a fish-rearing facility near Michigan‘s Kalamazoo River, I’m peering inside a big, water-filled tub at lake sturgeon eggs no bigger than BB pellets.

Someday these will grow into the biggest fish in North America, but for now, they’re the precious cargo of a state program to bring these freshwater giants back to their native habitat. (Read more about the world’s giant fish.)

lake sturgeon picture
A lake sturgeon seems to smile. Photograph by Joel Sartore, National Geographic

freshwater species of the weekTopping six feet (two meters) long and weighing nearly 200 pounds (90 kilograms), lake sturgeon once roamed rivers and lakes of the Mississippi River, Hudson Bay, and the Great Lakes. Unchanged from prehistoric times, the lake sturgeon has unusual features not seen in today’s fish, including an external skeleton that gives it an armored appearance.

But this ancient survivor has had trouble fending off human threats, including overfishing in the late 1800s, dams that have blocked migrations, and industrial pollution that has poisoned the fish’s spawning grounds. (Learn more about freshwater threats.)

Today there are genetically unique populations of sturgeons in at least eight rivers around Lake Michigan, with about 166 fish in the Kalamazoo River, according to Kregg Smith, senior fisheries biologist at the Michigan Department of Natural Resources.

No one knows how many fish once lived in the Kalamazoo. But Smith and others did know the fish—deemed a threatened species in Michigan—needed a helping hand.

lake sturgeon picture
A lake sturgeon hooked in the Kalamazoo River this year is released back to its environment. Photograph courtesy Kregg Smith, Michigan DNR

So, starting in 2003, Smith and a team of nonprofits, the U.S. Fish and Wildlife Service, and native tribes set up the streamside rearing facility, which raises juvenile fish and releases them back into the rivers. So far they’ve sent 116 young fish back into the river, where they’ll eventually end up in Lake Michigan.

No Place Like Home

Inside the Kalamazoo River facility—a small trailer near a stand of trees a few hundred feet from the river’s banks—and USFWS fisheries biologist Elliott Kittel is showing me an image of a sturgeon egg zoomed in on a laptop.

sturgeon egg
Elliott Kittel shows a picture of a sturgeon egg zoomed in on his laptop at the Kalamazoo River streamside rearing facility. Photograph by Christine Dell’Amore, National Geographic

Just days from hatching, I could see its curved backbone and healthy, clear yolk sac. In the wild, most of these babies wouldn’t make it—a female sturgeon can spawn millions of eggs, and “99.9 percent mortality is a good day,” Kittel said.

But eggs and larvae brought up in the rearing facility have better odds, since they’re less vulnerable to predation, disease, and starvation.

The sturgeon team’s strategy centers around rearing the young fish in water pumped from the Kalamazoo River, thus “imprinting” the juveniles with the chemical signature of the river. (Test your freshwater IQ.)

 

picture of a sturgeon rearing facility
Young lake sturgeon are raised in this trailer near the Kalamazoo River. Photograph by Christine Dell’Amore, National Geographic

Sturgeon live most of their lives in lakes, but are born in rivers and return to the same place to spawn—for males, that’s every two years; for females, every four to six. So the biologists hope that when the human-raised sturgeon grow old enough to spawn, they’ll “home” to the place where they were born.

This reduces the possibility that sturgeon will wander into other rivers, where the wayward fish could breed with other populations, diluting their genes. (See other pictures of megafishes around the world.)

As another backup, scientists take eggs that are naturally spawned by females living in the Kalamazoo and raise them in the rearing facility.

Males are sexually mature at 10, but females don’t start breeding until about 22 years of age. Sturgeons are incredibly long-lived, sometimes reaching over a hundred: A specimen caught in Canada in 1953 was 152 years old, according to a 1954 article in the Milwaukee Journal.

Once the babies hatch, the biologists get them up to about 6 to 10 inches (15 to 20 centimeters) long, tag them, and release them into the river in the fall. The team then monitors the fish to see if they return to the river to spawn.

Kalamazoo River picture
Once they’re about six months old, lake sturgeon are released into the river. Photograph by Christine Dell’Amore, National Geographic

But the sturgeon team will have to wait until 2021—when the first released males turn 10—to see if they come back, Smith said.

Personable Fish

To the people trying to save this unusual fish, there’s just something about sturgeon.

Ron Clark, a volunteer with the nonprofit Kalamazoo River Sturgeons for Tomorrow who was helping out at the Kalamazoo facility, said that being part of an effort to save such an ancient species “intrigued me.”

Clark, who has found the fish docile and easy to handle, said they seem to have individual personalities … they’re more like a [mammal] than a fish.”

Fisheries biologist Smith added that he likes the look of the prehistoric fish and its weird adaptations. For example, sturgeons have spiracles, which are holes in the side of the fish that allow them to breathe along with their gills.

He added that bringing the sturgeon back would give the public a chance to learn about a fish that had to survive during the dinosaur era.

“It’s the most unique fish in the Great Lakes.”

This story was made possible in part by a fellowship from the Institutes for Journalism & Natural Resources.

Comments

  1. ramlix
    Rizal , Philippines
    February 19, 4:26 am

    wow thats nice , keep adding more fishes so it would e great. add some freshwater ornamental fishes like gourami etc

  2. Matt Horns
    Los Angeles
    February 11, 11:39 pm

    The largest freshwater fish in North America is the white sturgeon, which can grow to more than 1000 pounds.

  3. Rose Marie Puro Bolivar
    Jaro, Iloilo City, Philippines
    October 4, 2013, 6:32 am

    Congratulations Elliott! Continue the good work. We love you!

  4. Stefan
    Tulccea
    May 27, 2013, 6:52 am

    Very interesting ! Congratulations!

    http://rosturgeons.wordpress.com/

  5. Sennepin Alain
    St Priest, Loire, France
    May 19, 2013, 7:00 am

    AN EURASIAN POINT OF VIEW.
    All my congratulations, Christine.
    I am Alain Sennepin
    webmaster of
    4 continents pour les tigres
    http://www.avenir-tigres.com
    It’s easy to show that’s in Eurasia, tigers and sturgeons are inseparable both in ecological functionnality as well as on a cultural, religioius, sociopolitical point of view.
    My personal diagnostic and pronostic for tiger Panthera tigris, realized last month, can be obtained from homepage of my website (in french).
    I could also send you a strong english summary if you are interested (see my e-mail adress).
    Beginning of recovery, recent past, ancient past with tigers on several continents and ancient social as well as technical competences in human communities, tigers in oriental Europe, ecological and sociopolitical elements for future, anhistoric tiger and man intimaty .
    SociopoliticalSymbiosis between men, tigers and sturgeons paragraph 3.
    Ichtyochory, sturgeons, salmons, boxhead and right whales, Historical mutualism between fishers and whales in Norwegia, paragraph 4.
    Best regards.
    Alain Sennepin