JEFFERSON COUNTY, Colo. – The bone-chilling cold-snap didn’t stop some state workers from getting out on the water Wednesday morning.

A team of aquatic biologists with Colorado Parks and Wildlife had planned a research project this week at Chatfield Reservoir to study the growth rate and population of walleye. The data will help them maintain the population of the fish in the lake.

“We are going to be collecting ear bones called otoliths out of the fish,” aquatic biologist Paul Winkle told FOX31. “When you look at them under a microscope, they have rings just like trees and you can age the fish.”

In order to collect the fish, CPW had to shovel several inches of snow from the north boat ramp at Chatfield State Park. Their boats were also frozen to the trailers when they first tried to launch.

“Five. Five degrees this morning,” Winkle said.

He says they couldn’t postpone the research another day because they needed to collect the fish while the water temperature was within a certain range. Waiting until next week would mean the water would be too cold to proceed.

“We knew it was going to be cold. We knew there was going to be some snow. But we’ve got to get the work done,” Winkle said.

The work included some unforeseen challenges, however.

“Well, yeah, cold hands. And so trying to pick the fish out of the net with cold hands can be challenging sometimes because you can’t feel your fingers,” Winkle said.

After dunking their hands in and out of the water for several hours, many team members were working with their winter gloves encased in ice.

They compensated for the cold with as many as six layers of clothing to keep warm.

“That’s what makes it interesting. You’re not always out there on those bluebird sunny days when it’s warm,” Winkle said.

After dissecting the walleye to collect the data, the fish were filleted and donated to a homeless shelter in Denver.