Chris Hill holding a pikeElectrofishing at nightBag of PikePike width Yampa River Northern Pike Exclusion Studies

Project Officer: Eric Bergersen

Graduate Student: Chris Hill

Funding Agency: Colorado Division of Wildlife

Introduction: The northern pikes first arrival in the Yampa Valley occurred with its stocking in Elkhead Reservoir, a reservoir located on a tributary stream to the Yampa River. Pike escaped from this reservoir and have proliferated in the Yampa River ever since. The northern pike is considered a serious predator on native fish in the Yampa River. Current management of northern pike in the Yampa River includes a pike removal project conducted by the U.S. Fish and Wildlife Service and elimination of possession limits for anglers.

Objectives:
1. Determine where and when northern pike are spawning in the Yampa River.
2. Determine whether a low cost screening material could prevent northern pike from gaining access to their preferred spawning habitat.
3. Evaluate the feasibility of using a temporary screening device on all spawning sites between Steamboat Spring and Craig, Colorado.

Progress: Reduction of northern pike has been identified as a key step in the recovery efforts for endangered fish in the Yampa River. We evaluated the effectiveness of barriers to backwater spawning habitat as a way to limit northern pike Esox lucius spawning success and thereby reduce recruitment. Potential backwater spawning habitat appeared to be abundant in the Yampa River, but high quality backwaters were limited. The majority of backwaters showed signs of receiving flushing flows during spring runoff, which calls into question the quality of backwaters as nursery habitat. Few age-0 northern pike were found in backwaters. Age-0 pike were much more abundant in samples from one off channel pond, suggesting that these areas may be a more significant source for young-of-the-year recruitment. In addition, northern pike movements from a reservoir to the Yampa River were documented. Fall installation of barriers was not effective because of damage from ice during the winter. Spring installation is feasible, but would need to be done in the limited amount of time before northern pike begin to spawn. The reluctance of some land owners to allow barriers to be installed on their property and the apparent low recruitment found in backwaters suggest that the time and money spent on installation may not be worthwhile. Future studies and management should be directed at the ponds and reservoirs, which appear to be important sources of northern pike recruitment into the Yampa River.

Plans: The research project has been completed and the final report has been submitted to the Colorado Division of Wildlife and the Recovery Program for approval.

Hill, Christopher. Spring 2004. Dynamics of Northern Pike Spawning and Nursery Habitat in the Yampa River, CO., M.S. Thesis.