Conservation Genetics of the Endangered Shasta Crayfish (Pacifastacus fortis)

Habitat loss due to hydrologic and agricultural manipulation has been detrimental to the Shasta crayfish population. However, even more harmful has been the introduction of non-native species including bullfrogs, muskrats, many fishes, and most notably, the signal crayfish (P. leniusculus). The only native crayfish endemic to California remaining in existence, the Shasta crayfish was state and federally listed in 1988; however, populations continue to decline. Up to this point, the genetic structure of the Shasta crayfish is unknown.  Working with the California Department of Fish and Game, and Spring Rivers Ecological Sciences, microsatellite markers developed in our laboratory have been employed to examine the extent of genetic diversity within and between the remaining populations of P. fortis in Shasta County, CA. The information gained from this study will be applied to management of this species in the hopes of protecting it from extinction.

Shasta crayfish habitat, Shasta County, California - Sucker Springs Creek (above) has been the site of substantial on-the-ground restoration efforts by Spring Rivers Ecological Sciences, LLC., including physical removal of signal crayfish and the installation of velocity barriers (right).   Shasta crayfish in Crystal Lake (below) have been sympatric with invasive signal crayfish for over 30 years.

For more information, contact Jessica Petersen (jlpetersen@ucdavis.edu).