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Study about predation on fishers in California
Topic Started: Jan 22 2012, 09:06 AM (1,172 Views)
Cat
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Omnivore
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Another of my entries from the old forum:

This study by Greta Wengert shows that predation is the most important factor in fisher's mortality in California:
http://snamp.cnr.berkeley.edu/static/documents/2011/07/22/Jul-14-2011_FisherIT_GretaWengert.pdf
Predation frequently occurs on healthy adult fishers and the most important predator is the bobcat, followed by the mountain lion and the coyote. It seems bobcats prey on female fishers however.
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Ceratodromeus
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More recent study confirming bobcats and mountain lions are the main source of predator induced mortality(a combined 78% of all cases). Additional predators include the coyote, domestic dogs, and the Northern Pacific rattlesnake.

Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore, the Fisher (Pekania pennanti) in California

Abstract
Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species.
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"Of the 90 fishers that died from predation, necropsy examination confirmed 58 predation events. The remaining 32 fishers had insufficient tissues for a full necropsy and were classified as predation events via molecular forensics and/ or ante-mortem hemorrhaging from wounds on remaining tissues. Specific predators of fishers could be determined for 67% (n = 60) of all predation events based on molecular forensic evidence; eight more were identified only to family, specifically Felidae. Of predators identified, bobcats (Lynx rufus, n = 27: 40%), mountain lions (Puma concolor, n = 26: 38%), unidentified Felidae (n = 8: 12%), coyotes (Canis latrans, n = 4: 6%), and domestic dogs (Canis lupus familiaris, n = 2: 3%) were confirmed predators of fishers while a single fisher (1%) was killed by a rattlesnake (Crotalus oreganus oreganus)."
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0140640
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