Attentive angler and fisheries sleuthing tell tale of silver carp
Rich Russell and his son Bennett, both of Stoughton, had a pretty normal evening of catfishing July 30, 2022, on the Wisconsin River.
But after they reeled in and headed back to the boat landing below the Prairie du Sac dam, the outing earned the tag of unprecedented.
Rich, 31, was at the tiller and Bennett, then 9, was in the front seat with his back toward the bow.
As they were motoring slowly toward shore about 10 p.m., a large fish erupted several feet out of the water, careened into the boat and struck Bennett on the arm and side.
“It was like chaos for a minute until we realized what happened,” Rich said in a recent phone interview. “It was banging around and knocking our gear all over. I had to put my foot on it while I tried to keep my son calm.”
Bennett was shaken up, Rich said. And no wonder. The fish was 35 inches long and weighed 20 pounds. The unexpected projectile in the dark produced a frightening wallop.
It would have been understandable if it had taken the Bennetts a lot longer than a minute to comprehend the incident; it was the first time it happened on the Wisconsin River.
The fish was a silver carp, an aquatic invasive species known for causing ecological damage to freshwater fisheries in the United States as well as for its habit of leaping out of the water and into boats.
Silver carp and bighead carp have been working their way north in the Mississippi River since escaping decades ago from fish farms in the southern U.S. Both species have been found for at least 15 years in the Wisconsin waters of the Mississippi.
After Russell, an avid angler, got a good look at the fish in his boat, he knew what it was. He’d seen posters at boat landings warning anglers and boaters of the potential of the invasive carp in the Wisconsin River.
But while bighead carp had been found in the Wisconsin River, a silver carp had yet to be documented.
As a responsible fisherman, Russell knew what to do. He took the fish home and called the Wisconsin Department of Natural Resources to report it. He also posted a photo of it on the Wisconsin River Fishing Facebook page.
The next day he received a text from Bradd Sims, DNR stream and river systems biologist, and within a day the fish’s head was picked up by the DNR and transferred to the U.S. Fish and Wildlife Service for testing.
Why the head? That’s home to the otoliths, or ear bones, which allow scientists to determine age and even where the fish was spawned.
Similar to rings in a tree, minerals are deposited in the otoliths as a fish ages; each line represents a year.
A technology called otolith microchemistry was also applied to the silver carp collected by the Russells. In this case, the concentrations of elements and isotopes in the ear bone were measured and compared to those found in the environment.
The scientists look for a match with other samples analyzed and kept on file.
The same technology is being used to help identify key chinook salmon, coho salmon and steelhead spawning rivers in the Great Lakes as well as lake whitefish breeding sites in Green Bay and its tributaries.
Charles Bronte, USFWS fisheries biologist based in Green Bay, has been using otolith microchemistry for about 20 years to help answer questions on the Great Lakes.
“The nice thing about the otoliths, as opposed to some fins or scales, is they are always there,” Bronte said. “You have a permanent, natural tag in each fish that can tell age and where it’s from. It’s cool stuff.”
On Jan. 25 Russell found out a whole lot more about the 20-pound fish that collided with his son.
Analysis by the USFWS found the silver carp was spawned in 2016 in the Mississippi River near Lock and Dam 19. The dam is near Keokuk, Iowa, near the borders of Iowa, Missouri and Illinois. The Mississippi and other rivers in that area are thick with silver and bighead carp.
The silver had traveled north to the confluence of the Wisconsin River, then northwest in the Wisconsin to the Prairie du Sac dam, the first impediment on the river.
There its migration was thwarted and it went undetected until its fateful leap last July into Russell’s boat.
We can hope all silver and bighead carp also get stymied by the dam. And of course wish for strategies or technologies to remove the invasive carp from all our waters.
Work is continuing to find such solutions.
For now, Russell has provided the angling community with a textbook example of how to deal with an invasive carp.
Knowledgable anglers and other members of the public, coupled with effective law enforcement and smart, science-based fisheries management are our best bets to deal with aquatic invasive species.
Kids ice fishing clinics set for Saturday
Volunteers with local clubs will teach ice fishing skills Saturday at the annual Ice Fishing Clinics for Kids at seven sites in Milwaukee County. The events are free and will feature instruction in ice safety, fish identification, fishing gear and fishing tactics.
The clinics are intended for youth ages 15 and under; all children must be accompanied by an adult. The clinics start on the hour from 9 a.m. to 2 p.m. They will be held at the following Milwaukee County Park properties: Brown Deer, Dineen, Greenfield, McCarty, McGovern, Scout Lake and Kosciuszko.
The events are sponsored by the Wisconsin Council of Sport Fishing Organizations, Hunger Task Force, Milwaukee County Parks and the Wisconsin DNR.