Current distribution of the fisher, Martes pennanti , in California

Wedescribe the 1989-1994 distribution of the fisher, Martes pennanti, in California based on the results of detection surveys that used either sooted track-plates or cameras. Fishers were detected in two regions of the state: the northwest and the southern Sierra Nevada. Despite considerable survey effort, neither fisher tracks nor photographs were collected in the area between Mt. Shasta and Yosemite National Park. This represents a significant breach in the distribution formerly interpreted as continuous. Detection survey results suggest that the population in the southern Sierra Nevada may be isolated from populations to the north. We recommend that additional survey effort be focused on the southern Cascades and northern Sierra Nevada and that forests of the Sierra Nevada be managed to encourage the movement of fishers between these areas. We also recommend that descriptions of the current distributions of uncommon carnivores be based on techniques that produce verifiable records rather than summaries of incidental sightings.