Electrofishing Removal to Control Exotic Brook Trout

Nonnative brook trout are abundant in Pine Creek and its tributary, Bogard Spring Creek, California. These creeks historically provided the most spawning and rearing habitat for endemic Eagle Lake rainbow trout. Three-pass electrofishing removal was conducted in 2007–2009 over the entire 2.8-km length of Bogard Spring Creek to determine whether brook trout removal was a feasible restoration tool. After the first 2 years of removal, brook trout density and biomass were severely reduced from 15,803 to 1,192 fish/ha and from 277 to 31 kg/ha, respectively. Average removal efficiency was 92–97%, and most of the remaining fish were removed in the third year. The lack of a decrease in age-0 brook trout abundance between 2007 and 2008 after the removal of more than 4,000 adults in 2007 suggests compensatory reproduction of mature fish that survived and higher survival of age-0 fish.  Although  labor intensive, the use of electrofishing to eradicate brook trout may be feasible in Bogard Spring Creek and similar small streams if monitoring are continued annually. Our evidence shows that if control measures continue and if only rainbow trout are allowed access to the creek, then a self-sustaining population of Eagle Lake rainbow trout can become reestablished.