Genetic variation and structure of fisher (Martes pennanti) populations across North America

Fishers are mid-sized forest carnivores indigenous to North America that ex perienced sharp population declines from the early 1800s through to the mid -1900s. To evaluate levels of genetic variation within and subdivision amon g northern fisher populations 459 individuals were genotyped using 13 micro satellite loci. Genetic diversity was found to be slightly lower in re-intr oduced populations than in adjacent indigenous populations. Furthermore, fi sher populations revealed much more genetic structuring than two closely re lated mustelids. Further investigation is needed to determine if fishers ar e more philopatric than martens and wolverines or if barriers to dispersal explain the levels of structure identified in this study.