I looked up from fawning over some orange California newts just in time to spy a fuzzy whiskered face peering out from the waters of the creek. Weasel-like features and silky-smooth contours gave away the creature’s identity: Lontra Canadensis, the North American river otter.

As soon as we made eye contact, she flipped her body up into the air and dove down below the sunset-bathed water, offering me but a single glimpse of her splendor before disappearing into the depths.

The moment was brief yet unforgettable. I couldn’t help but feel special that this cute little creek-dweller had splashed “hello” to me (or was it something else?). Camped in northern California’s Ishi Wilderness in the Cascade foothills, I presumed that city slickers back in the Bay Area could only dream of witnessing such a display.

A few years ago, I would’ve been right. But today, river otters are making a splashy showing in the Bay Area’s waterways, according to a new project that’s been keeping tabs on them.

Naturalist Megan Isadore says she was inspired to co-found the River Otter Ecology Project (ROEP) when she started noticing the sleek water weasels in Lagunitas creek in Marin, where she was studying endangered Coho salmon.

“We thought, ‘Well, there must be more than we thought,’” recounts Isadore. “So we decided to count them.”

Motivated by just how little was known about the elusive creatures, Isadore and co-founding ecologist Paola Bouley kicked off the ambitious project in February 2012. Their goals? Figure out how many river otters live in the Bay Area, study their population and family dynamics, and learn about their ecological requirements for survival.

Up until 1962 when river otter trapping was banned, the animals were hunted — much like their sea-faring cousins — for their thick insulating fur. Add river pollution to the mix, and you have a situation where very few river otters were seen in the Bay Area, Isadore says. “As of the 1995 Department of Fish and Game records, the map shows no river otters whatsoever in the Bay Area,” Isadore says. “They were largely extirpated from this area likely by the 30’s or 40’s, but that’s just a wild guess on my part because there are no records.”

Isadore and Bouley’s increasingly frequent otter sightings in Bay Area creeks led them to start ROEP, which calls on citizen scientists to report otter sightings to their website. Since February of 2012, 380 sightings have been reported by these so-called “Otter Spotters,” and mapped here. While a majority of the otters have been spotted in the northern reaches of the bay, more otters are springing up in the east and south bay, with the most southern sighting in Lake Vasona in Los Gatos.  Although the project started in the north bay, Isadore hopes to soon expand otter spotting further south.

ROEP is teaming up the California Academy of Sciences to conduct genetic sequencing on hair, scat, and “otter jelly,” an anal secretion thought to protect against the sharp edges of shells and bones that otters ingest.  “The reason we’re so excited about the jelly is because it’s pure otter DNA, rather than it being mixed with prey species like in scat,” Isadore says.

ROEP has placed 22 infrared trail cameras all over the north bay, which have captured alluring video of the elusive otters in action. Isadore hopes to use a combination of observation and genetic mapping to learn more about the way the otters interact with each other, what they like to eat, and what measures we might take to keep them coming back for more.

River otters are “sentinel species,” meaning their vigor is a good predictor of overall ecosystem health. Otters are particularly sensitive to waterborne toxins such as PCBs, mercury, and organochlorines, and their high position on the food chain makes them susceptible to contamination of the creatures they feast upon as well. So their comeback could be a welcome reward for efforts to cleanup waterways. “The more we can restore the Bay Area water shed, the more likely we are to see river otters,” Isadore says. “People like that.”