March 30, 2017
Spring ritual plays out over three intense weeks at Lake Pueblo
PUEBLO, Colo. - In a cramped little boathouse in a backwater cove on the north shore of Lake Pueblo State Park, a dedicated team of Colorado Parks and Wildlife staff and volunteers are putting in long hours over an intense four-week period to ensure a bumper crop of walleye and saugeye in state lakes and streams this summer.
The teams are led by CPW Aquatic Biologist Carrie Tucker and the action begins at about 7 a.m. each day, seven days a week, during the spring walleye spawning season.
Two boats leave around dawn each day to empty 32 large nets placed in shallow water around the popular reservoir the previous afternoon. Any walleye caught in the nets are placed in a live well on the boats and brought back to the boathouse.
Inside the boathouse, a dozen or so volunteers sort the slippery, wiggling fish into holding tanks. Then the fish make their way down an assembly line where, one by one, the female walleyes are massaged and stripped of their roe, or eggs, and the males of their milt, or semen, which are then carefully mixed in plastic tubs with filtered lake water.
Volunteers, including Bill Shumaker and Jim Thomas, carefully add water and gently stir each pan with a feather to ensure maximum fertilization of the thousands of eggs in each tub.
Meanwhile, as the egg fertilization process goes on all around them, still more volunteers spend hours untangling, repairing and repacking huge tubs of nets so the whole process can be repeated the next day.
Even then, the work of the volunteers isn’t finished. Before releasing the spent walleye, the volunteers weigh and measure many of the fish and take scale samples, carefully collecting and logging important data for biologists to study.
This spring ritual has been going on for decades and is repeated, simultaneously, by CPW staff and volunteers at Cherry Creek State Park and Chatfield State Park near Denver.
The work goes on until the biologists reach their goal for fertilized eggs, the spawn ends, or the lake water temperatures rise resulting in too many other species being caught.
“We’re trying to collect about 124 million eggs statewide this year,” Tucker said. “That’s the number the hatcheries said we need to satisfy requests from CPW aquatic biologists and for trades with other states.”
Most of the eggs go to the Pueblo Fish Hatchery below the reservoir dam. There, they are inserted into tall plastic cylinders where they develop from eggs and hatch into small fry.
Within days, the tiny fry are able to swim up and out of the cylinders into large tanks where they further develop. About 12 million will be released back into Lake Pueblo while the rest will be distributed to other reservoirs in Colorado and traded to other states in exchange for catfish and other species.
On one day last week, the CPW staff and volunteers collected about 2.8 million eggs - a very good haul.
And this work goes on in good weather and bad. And often in early spring, the weather is lousy.
“We get rain, sleet, snow and wind,” Tucker said. “The wind is the worst. If it gets bad enough, it’s about the only thing that stops us from going out each day.”
And that’s exactly what happened last week when a powerful storm pounded Lake Pueblo with winds gusting to 75 mph and more, destroying docks and sinking boats in the adjacent Northshore Marina. The dock to the boathouse was damaged and the spawn operation was suspended for the day.
But the team was back out the next day performing midwife duties on the lake’s walleye.
So much effort is made to ensure a strong walleye population because anglers have grown to love chasing the challenging fish in the waters of eastern Colorado. Walleye have been stocked in state reservoirs since around 1949.
Walleye spawn in the spring when water temperatures reach about 40 degrees. Females typically look for shallow, rocky areas to deposit their eggs. Males then follow and fertilize them.
But incubation and hatch rates fluctuate depending upon predation, water temperature and water levels. The work by Colorado Parks and Wildlife biologists ensures a much greater rate of survival and hatch of the walleye. Even with the help of CPW biologists, the survival rate of walleye fry that reach an adult or catchable size is usually less than one percent.
Besides providing millions of walleye eggs to stock Colorado lakes, CPW uses excess walleye eggs to trade with other states for species such as catfish and wiper. In fact, CPW stocks about 90 million fish of all species annually into waters throughout Colorado.
Spawning efforts at Lake Pueblo are expected to wrap up by April 5 or so.
Top photo: Colorado Parks and Wildlife staffers John Nehring, senior aquatic biologist, and Carrie Tucker, aquatic biologist, strip roe, or eggs, from a female walleye during spawning operations last week at Lake Pueblo State Park.
Middle left photo: A team of Colorado Parks and Wildlife staff and volunteers, led by Carrie Tucker, aquatic biologist at left, head out to pull nets and collect walleye for spawning operations at Lake Pueblo State Park.
Middle right: A Colorado Parks and Wildlife staffer removes netting from a walleye caught for spawning operations at Lake Pueblo State Park.
Bottom left: Carrie Tucker, aquatic biologist, holds a female walleye prior to stripping its roe, or eggs, during spawning operations at Lake Pueblo State Park.
Bottom right: Millions of fertilized walleye eggs fill cylinder tubes at the Pueblo Fish Hatchery where they will develop into tiny fry and eventually will be stocked into Lake Pueblo and other reservoirs across eastern Colorado.
CPW is an enterprise agency, relying primarily on license sales, state parks fees and registration fees to support its operations, including: 42 state parks and more than 350 wildlife areas covering approximately 900,000 acres, management of fishing and hunting, wildlife watching, camping, motorized and non-motorized trails, boating and outdoor education. CPW's work contributes approximately $6 billion in total economic impact annually throughout Colorado.