Invasive Fish Removal for Habitat Restoration at Mountain Lake in the Presidio of San Francisco: Rotenone Use in an Urban National Park

One of only three natural lakes in San Francisco, Mountain Lake’s, ecosystem was degraded through the introduction of invasive non-native species. Ecosystem restoration was desired by community groups and required by San Francisco Regional Water Quality Control Board as part of an environmental remediation clean-up effort. Ecosystem restoration hinges on the establishment of submerged aquatic vegetation. Such vegetation could not successfully reestablish in the presence of non-native carp foraging in bed sediments. A fish removal effort was undertaken. Non-chemical fish removal efforts proved unsuccessful. The use of rotenone was determined to be the only means of ridding the lake of sediment-foraging fish. A strategic public campaign led to community support of the project, and an application of rotenone led to the eradication of fish at Mountain Lake. Efforts are ongoing to prevent reintroduction of invasive species. Reintroduction of native plant and reptile species has begun. Reintroduction of native fish species are expected to begin in spring 2015.