Local fish population gets a boost
One of the Iowa DNR’s stocking trucks, releasing fish into the water. “You can't see the fry when they're shot out of the tube into the water because they're so small,” said Fisheries Biologist Ben Wallace. (Photo by Ben Wallace.)
DNR releases over 1 million newly-hatched walleye in North Twin Lake
By Cassandra Kyser
Excellent fishing opportunities in Calhoun County don’t happen by chance. Some fish species, like walleye, need a little help to thrive.
North Twin Lake, like many other lakes in the state, are stocked with fish by the Iowa Dept. of Natural Resources.
Walleye are a special focus of the DNR, as the agency reports, “With little natural reproduction in most Iowa lakes and rivers, Iowa’s walleye populations depend on stockings.”
Fisheries Biologist Ben Wallace helps stock North Twin Lake. He shared that this spring, 1.36 million tiny “fry” — the name for newly hatched walleyes — were released in North Twin Lake.
While that sounds like an incredible number, at ⅓ of an inch long, baby walleye are barely detectable by the human eye. And, not all of them will survive to adulthood. Some will fall prey to larger fish.
The DNR will return to North Twin Lake in the fall to release another 4,530 “fingerlings” — young walleye that are approximately six inches in length.
According to Wallace, in addition to walleye, the DNR stocks North Twin Lake with other fish, including approximately:
• 4,500 Hybrid Striped Bass fingerlings, two inches in length, in the late summer
• 230 Muskellunge advanced fingerlings,12 to 14 inches in length, in every odd year during the spring
• 1,360 Channel Catfish advanced fingerlings, eight inches in length, every even year during the fall
“The other species take care of themselves through natural reproduction,” explained Wallace.
The DNR also stocks Roos Pond — which is just south of Rockwell City off Norridge Ave. — with Channel Catfish during even years.
Two sources of the DNR’s walleye fry and fingerlings are the Rathbun Fish Hatchery in Moravia and the Spirit Lake Fish Hatchery.
Each spring, DNR crews work overnight, catching walleye at East Okoboji Lake and Spirit Lake via gillnets. The caught fish are brought to the fisheries, where their eggs are removed. The fish are then returned to the lake where they were caught.
The fertilized eggs incubate in the protected setting of the hatchery, until they hatch. Some fish are released almost immediately, as young fry. Others will mature several months until they are fingerlings.
In total, there are five DNR hatcheries throughout Iowa, and all are open to the public on various days. Visitors can see walleye and other fish species up close and in various stages of growth. To plan a visit to a hatchery, go to iowadnr.gov/about/hatcheries.