Conservationists are celebrating the return of sturgeon to the Milwaukee River – 20 miles upstream from Lake Michigan.
It’s the first time one of the giant fish was documented in Ozaukee County in more than a century.
Sturgeon disappeared from the river due to factors including overfishing and degraded habitat.
The discovery of the sturgeon so far from Lake Michigan signals a milestone in a massive sturgeon restoration project that’s been underway for 20 years.
It started when the Wisconsin DNR formed a partnership with Riveredge Nature Center in Newburg to restore lake sturgeon to the Milwaukee River.
The DNR began traveling to northeastern Wisconsin along the Wolf River, where sturgeon have a healthy spawning scene.
DNR teams would harvest sturgeon eggs along the river’s edge then drive them to Riveredge Nature Center, where its staff and volunteers turned a trailer into a rearing station for sturgeon. Water from the adjacent Milwaukee River was pumped into fiberglass tubs where the baby sturgeon are nurtured.
I met then-Riveredge researcher Marc White there a few years into the restoration project. The small creatures rocketed around the tank.
"This is their cutest life stage. If you don’t love a baby sturgeon, you’re not going like the adults. The adults are like creatures from some other planet," White said.
It’s hard to believe these minute hatchlings could one day be 7 feet long and weigh up to 300 pounds. "The real big challenge is getting the sturgeon to survive for the first two to three months of life when they’re just very fragile," White said.
But for the past couple decades, more than 19,000 young sturgeon survived and were released at the fingerling stage where the Milwaukee River meets Lake Michigan.
The hope is that eventually they’ll make their way back upstream and restore their historical spawning habitat.
A decade ago, I joined DNR fisheries technician Tom Burzynski on a boat, to watch him monitor how sturgeon were faring beyond the breakwater in downtown Milwaukee.
“Once they get to a certain size, it’s like over 85% survival. I mean, if they get to be 12 or 14 inches long, there’s not a lot that’s gonna eat them," Burzynski says.
Burzynski saw encouraging signs of a growing sturgeon population. He and colleague Jeff Zinuticz were elated when they netted a few juvenile sturgeon that day — one nearly 22 inches long.
Burzynski told me that sturgeon once were plentiful here. But by 1900, their numbers had plummeted. Their habitat had been degraded. And, “The commercial fisherman thought they were trash, and they’d just bring them up on shore and burn them or whatever. And then they found out the lining of the swim bladder can be used to clarify oils and jellies and such, make it nice and clear, so they decided to fish them," Burzynski said.
Sturgeon’s own biological clocks can be challenge. While they can live to be 100 years old, it takes a long time for them to reach spawning age.
Ozaukee County Director of Planning and Parks Andrew Struck say lots of partners collaborated to make the Milwaukee River reintroduction work.
That includes the removal of dams and creation of fish passages.
"North Avenue Dam, Kletzsch Dam, Estabrook Dam — all in Milwaukee County," Struck says. "And then here in Thiensville-Mequon Dam with the fishway that was constructed in 2009-10 and then reconstructed with the idea of making it even more suitable for passage by lake sturgeon."
Last week, Struck and other sturgeon supporters got proof that the trip upriver wasn’t just possible – it’s happening.
"We had the first adult male lake sturgeon come up from Lake Michigan," Struck says.
I met Struck at the Thiensville-Mequon Dam fishway, where an underwater camera captured video of the 50-inch-long fish on the move on March 30.
"The camera is immediately below us here at this culvert. And it’s kind of a pinch point for all migrating fish that are coming up the Milwaukee River," Struck says.
The video is brief and grainy, but the sturgeon can be seen clearly. Inch marks on a window that the fish swim past help researchers gauge the size. And a tag from when the sturgeon was released into the wild identifies it as a 15 year old – the age male sturgeon begin to spawn.
Time will tell whether a female sturgeon has made her way upstream.
"Females take a little bit longer to hit sexual maturity. So unfortunately, he may be making this journey and not find a partner, but we’re hopeful that there are some female sturgeon coming up," Struck says.
No matter what happens, he called the passage “truly a historic day for a historic fish”
And there was more to celebrate just two days later. The camera captured a second large male sturgeon swimming upstream.
To see a live feed of fish swimming through the fish passage where the sturgeon have been spotted, check out ozaukeefishway.org.
_
