Managing the Eel River’s pikeminnow problem

June 29, 2023

Gabe Rossi and Keane Flynn, a graduate student at the University of Nevada, Reno, examine the pikeminnow weir.

Recovery of steelhead, trout, and other salmonid species in northern California’s Eel River watershed has been threatened by pikeminnows over the past half century. Although they are native to California, pikeminnow are invasive to the Eel River and known to prey on or compete for resources with native fish.

To help further recovery efforts for native salmonids, the California Department of Fish and Wildlife recently issued a permit to start culling pikeminnows in the Eel River system. Research scientist Gabe Rossi and postdoctoral researcher Phil Georgakakos, who work in the lab of Cooperative Extension Professor Ted Grantham and with freshwater advocacy group CalTrout, are overseeing the development and deployment of an experimental weir on the River’s south fork.

While fish are able to move downstream freely through a chute, all migrating fish are herded into a pen as they move upstream. If effective, the system would allow native fish like salmon and trout to continue upstream while allowing for the removal of non-native fish. 

“If we can increase smolt survival and increase smolt growth, which has a big impact on ocean survival, and if we can decrease pikeminnow predation and interaction with the native fish, we are hopeful it can make a big difference,” Rossi said.

Learn more about the pikeminnow weir on the CalTrout website and in the video below.