Biologists removed a total of 538 northern pike from the Yampa River this year as part of the Upper Colorado River Endangered Fish Recovery Program
Biologists removed the larger, predatory northern pike as part of a multi-year study to improve the survival of endangered and other native fish in the Yampa River.
Of those 538 fish removed, 455 were transferred to local public fishing areas, 42 were used for various research studies and 41 died during handling and transport.
Gerry Roehm, the in-stream flow coordinator for the recovery program, said the number removed this year was good.
"There's no specific number target," he said. "But 538 is a good number. That's the largest we've ever removed in a single year."
Reports will come out later assessing the impact, he said.
"I expect there will be a report written soon analyzing the effects on the fish population and whethe\r this project will be continued," Roehm said.
After the report comes out later this year, Roehm said program directors would decide whether to continue the effort.
This year's program was part of a pilot program to assess what impact the northern pike were having on other species in the river.
Data compiled by the Colorado Division of Wildlife, which is overseeing the project conducted by the recovery program, demonstrated that the survival of young and juvenile fish was low in recent years, said Tom Nesler, native fish conservation program manager.
"Our data suggest the abundant game fish like northern pike, smallmouth bass, and channel catfish, as well as Colorado pikeminnow, are eating most of the young fish produced each year so the same thing may occur again in 2002," Nesler said at the start of the project.
"This will result in declining adult populations of native fish species over time. We expect the removal of large predators like northern pike from the river will improve survival of the native fish species, in part by reducing predation and competition for food."
The reduced river flows as a result of the ongoing drought might impact the habitat of smaller fish in the river even more, Nesler said.
"This may concentrate fish in remaining habitats, increasing their vulnerability to predation by the larger predators," he said.
CSU research John Hawkins, who participated in the project, said he thought the project went well.
"We've had positive interactions with people that we spoke with about the northern pike removal project," Hawkins said. "We worked closely with the CDOW, district wildlife managers and wildlife technicians in the Yampa Valley and at Rio Blanco Reservoir and appreciate their assistance. We also appreciate the cooperation and understanding of several landowners who provided us with access to their property along the Yampa River."
If the project continues next year, the public will know, said Bob Muth, recovery program director.
"Any proposed expansion of non-native fish removal efforts will be discussed publicly prior to implementation," he said. "We value our relationship with the community and will openly discuss this issue before any management actions are approved."