We present results from the first-ever study of populations of the North American River Otter, Lontra canadensis, in coastal habitats of the San Francisco Bay Area, California. Historically extirpated from the region, wild populations of this sentinel carnivore appear to have made a recovery in recent years. Utilizing a citizen-science network paired with field investigations in 2012 and 2013, we documented 1374 River Otter observations across 8 of 9 San Francisco Bay Area counties. We demonstrate that River Otters are reproducing, and report here on the 1st sightings in decades in Alameda, San Francisco, and Santa Clara counties indicating a possible gradual expansion of the species' range southward. Within our Intensive Study Area in coastal Marin County, conservatively estimated densities ranged from 0.21 to 0.32 River Otters/km, with otters inhabiting a range of habitats from freshwater to marine. A pilot assessment of disease and mortality indicates that otters are being exposed to pathogens such as Vibrio and that observable mortality was largely due to car-strikes. We also report on timing of mating, timing of pup-juvenile emergence, and pup-juvenile production. Despite large-scale ecosystem restoration actions underway across the San Francisco Bay Area, River Otters have been overlooked by resource managers. Being apex carnivores that not only directly benefit from restoration actions but also likely play a significant role in the outcome of recovery actions focused on endangered salmonids and waterfowl, we strongly recommend attention to their potential role as a keystone species in the San Francisco Bay Area.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 96 • No. 1