A shocking development

Crews use electricity to stun, remove non-native fish from Yampa

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Thirty years ago, Frank Pfeifer raised northern pike at a hatchery in North Dakota. He remembers loading them for shipment to Colorado, to be stocked in Elkhead Reservoir as sport fish.

In an ironic twist, today the manager of the Vernal Fisheries Office hunts down pike spawned by the pike he raised decades ago.

"If they had stayed in Elkhead and didn't have an impact on the river, we wouldn't care," said Pfeifer, a U.S. Fish and Wildlife Service employee.

But they escaped out the reservoir spillway and into the Yampa River, where they eat everything, including several species of native fish protected by the Endangered Species Act.

Pfeifer and his crew of five Fish and Wildlife employees have been trolling the Yampa River for the past week on boats equipped with 30 horsepower engines on the back and anodes on the front. The anodes --metal spheres hung from rods extended about 12 feet in front of the boat -- emit a positive charge of about 4 amps that temporarily stun fish, said Mark Fuller, a fisheries biologist.

On Wednesday morning, the crew put in the Yampa River about 15 miles east of Craig. Pike like calm, clearer water because they hunt by sight, Pfeifer said. So the crew stuck to the floodwaters extending off the main current of the river, trolling the tall grasses growing along the banks.

Netters man the front of the boat, and another man operates the motor. When a pike is shocked, it twitches. The crew spots the ripples and a netter nets the pike, then deposits it in his boat.

That morning, they pulled 42 pike from the river in about an hour and 15 minutes. Pfeifer called it an average morning. The week before, they pulled 102 pike from the same area.

The stretch of the Yampa the crew trolled was upstream from critical habitat for the humpback chub, pikeminnow, and razorback sucker -- all endangered species.

"Those have been reduced substantially. One major factor is non-native fish predation," Pfeifer said.

"We want to open a window of opportunity for those native fish to survive," Fuller said.

Pfeifer said it could prove problematic when the Elkhead Reservoir is drained next year to begin construction on the reservoir expansion. He said screens would be installed to try to keep more pike from escaping into the river.

Pfeifer also collected pike from the Yampa last year, but those fish were marked and re-released. During this year's catch, the crew compared the number of newly captured fish to recaptured fish to determine how many pike are in the river. Last week, Pfeifer said only about 20 percent of the fish caught were recaptures.

Once the crew fished out a stretch of floodwaters, they recorded the captured fish, marked them with a tag, and hauled them to a stock pond near Hayden to be released.

Some anglers oppose Fish and Wildlife's policy of pike removal because they like to fish the pike from the river, Fuller said. But access to the river is limited, and often a boat is needed to get to the best pike habitat. Fuller argued that by moving pike to stock ponds, Fish and Wildlife makes pike fishing more accessible to the general public.

"The pike eats everything, so as far as I'm concerned, (removing them) makes the fishing better," said Don Driscoll, a Hayden resident fishing at the stock pond when Fuller drove there to drop off the captured pike.

Driscoll caught four pike that morning. He said he enjoys fishing the Yampa River for rainbow trout, but pike have eaten many of them, making the fishing poor, he said.

Pfeifer's crew planned to finish out Wednesday by fishing down the river as far as Yampa Valley Golf Course. By Friday, they planned to have made it to Colorado Highway 13.

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