Ultimate fish fry: Bark River Hatchery gives nature a boost
By Anna Marie Lux, Janesville Gazette, Sunday, April 24, 2016
FORT ATKINSON—Doug Lubke wonders where the walleye eggs are.
He and Mark Baldock have searched for them in the Rock River several miles upstream from Lake Koshkonong.
“We have found fish in all different spawning conditions,” Lubke said. “But we haven’t found any ready to give up their eggs. We don’t know if the walleye went farther upstream or if they went somewhere else.”
The fisheries technicians with the state Department of Natural Resources are in charge of the ultimate fish fry.
In a normal year, they collect anywhere from 1 million to 2 million walleye eggs in early April, hatch them at the Bark River Hatchery in Fort Atkinson and release the fry into the river to supplement natural reproduction.
Not all fry live to adulthood.
“We think that less than 1 percent will survive three years to become adults,” Lubke said.
All kinds of predators eat them during their first year.
Lubke suspects the early warmup in March followed by a cold spell affected the spawning, which is triggered by the length of daylight and water temperature.
He remains hopeful they can still collect eggs of one of the most sought-after fish in Wisconsin.
Lubke and Baldock had better luck gathering northern pike eggs in March.
They set out nets to catch fish.
“When the female fish are ready, just lifting them out of the water will start a stream of eggs,” Lubke said.
They fertilized the eggs in the field in a process called milting.
“We literally hold the male over the eggs as it releases the milt or sperm,” Lubke explained.
At the hatchery, fertilized northern pike eggs were kept in a container, where fresh water flowed from bottom to top. The eggs hatched in nine days.
Eventually, fry spilled out of the container onto a water slide and then into a large holding tank.
Initially, they got nourishment from their own yolk sacs. Eventually, they swam through a tube into the Rock River on the northeast side of Fort Atkinson.
An estimated 400,000 northern pike fry were released this spring, but only 1 percent will survive to adulthood.
Lubke believes in the effort.
“We figure any eggs we can add to natural reproduction is a bonus,” Lubke said. “We are happy to get some eggs into the river. It helps the whole system grow.”
He and retired DNR fisheries leader Don Bush came up with the design and structure of the system to hatch eggs in the early 1990s.
“It’s such a simple project with a demonstrated benefit,” Lubke said. “We stock two species of fish that anglers are eager to pursue.”
The Bark River Hatchery, located in a small building, operates for two months in spring. About 50 million fish have hatched there and have been released since the early 1990s. In the beginning, the DNR also collected sauger eggs but does not hatch them anymore.
“Sauger are now maintaining themselves from fry released in the 1990s,” Lubke said. “Prior to that, few or none were on this stretch of the river.”
Baldock is proud to be part of the hatchery effort.
“How can you not want to be part of a project that benefits the people of the state,” he said. “I’m passionate about providing a viable resource for generations to come.”
A group called Bark River Hatchery Partnership held a banquet last month to raise money for operating costs of the hatchery, except the salaries of DNR personnel.
“Funding from other groups and individuals is coming to an end,” said Adam Walton of Edgerton, who chairs the fundraising partnership and runs a fishing guide service. “We want to keep the hatchery running, so we resumed the fundraising banquet.”
Until a few years ago, the banquet was held annually to support the hatchery, which needs $8,000 a year to operate.
“The hatchery has done a phenomenal stocking job,” Walton said. “People are coming from all over the state to Lake Koshkonong to fish, which is good for local businesses and everyone.”
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