2013-10-27 by Will Kane from "San Francisco Chronicle" [http://www.sfgate.com/science/article/Otter-signals-Lake-Merritt-ecosystem-s-comeback-4929113.php]:
A river otter climbs a dock at Lake Merritt early this month, inspiring hope for the lake's future. Photo: Greg Lewis, Courtesy
Greg Lewis had just finished his evening row on Oakland's Lake Merritt when he saw a slick, squirmy, furry bundle hoist itself out of the water and onto the edge of the dock.
It was a river otter, the first one spotted in Lake Merritt in decades.
"I saw his head pop up and saw him pull himself on the dock," Lewis, 53, of Berkeley, said of the surprise Oct. 6 encounter. "He looked at us, we looked at him for a bit."
Lewis, who develops air pollution monitors, snapped a few shots, and like that, the animal plopped back into the water and paddled off.
No one has reported seeing the otter since, and biologists ordered Lewis to keep his mouth shut until they were sure the popular, photogenic animal wasn't going to make the lake a home.
But the sighting alone is proof, experts said, that Lake Merritt is making a comeback.
"It is one indication that the lake is getting healthier," said Richard Bailey, executive director of the Lake Merritt Institute, a nonprofit that monitors the lake. "Another indication, just this week, was that we spotted an osprey on an island in the lake. We haven't seen one of those here in a decade."
Bacteria in the lake are at some of their lowest levels in years, and there's half as much trash floating in the lake as there was in 2005, Bailey said.
Revitalizing lake -
Oakland is trying hard to revitalize the lake. Oakland voters passed a $198 million bond in 2002 to spiff up the lake, and in February, the city inaugurated a new channel that will eventually restore the natural order by reconnecting the lake to the bay.
Before Oakland was developed, Lake Merritt was a brackish lagoon that would swell and shrink with the tide and was home to otters, sea lions and an extraordinary array of migrating birds.
As Oakland grew from a town to a city, it choked the lake's connection to the bay and started pouring sewage into the lake. The water stagnated, and wildlife fled.
But the appearance of a river otter might be a sign that that's all changing.
The otter was probably searching the Oakland Estuary for a new fishing hole when it swam up a culvert, squeezed between metal bars designed to keep trash from flowing into the bay and started exploring the 155-acre lake.
"It is exciting, but not particularly surprising," said Megan Isadore, the co-founder of the River Otter Ecology Project, a Marin County group that tracks river otter sightings across the Bay Area. "River otters are making a recovery in the Bay Area. They were gone from the Bay Area for a long time."
The North American river otter once lived in almost every creek and lake in Northern California. The fissipeds - animals with padded feet - are members of the weasel family. They can live in salt water, brackish water or fresh water and are agile on their feet, sometimes even climbing trees.
Threats to survival -
Russian and other European hunters killed thousands of river and sea otters, all so the ladies of the Victorian age could wear their thick, water-repellent fur coats. Habitat loss from construction of dams and canals also depleted the river otter ranks. Pollution, including mercury from gold mining, reduced the population further.
But increasingly, otters are being spotted across the Bay Area. Earlier this year, a young river otter frolicked at the ruins of San Francisco's Sutro Baths. The otter, dubbed Sutro Sam, was the first otter spotted in the city in almost a half century. Sam eventually left the baths.
It is not impossible, but unlikely, that Sam swam across the bay to Oakland. But it is hard to tell otters apart, Isadore said.
"We know that there are otters all over in the Oakland area, and otters have a pretty variable social life," Isadore said. "He was probably just exploring, came to visit and see if there are a lot of other nice fish for him.
"He probably was there for a few days, and then he went somewhere with better fishing," Isadore added.
Conrad Jones, a wildlife biologist for the California Department of Fish and Wildlife, said spotting an otter in Lake Merritt was "encouraging, certainly, but it is too early to say if what we are doing is paying off."
"The biggest milestone," Jones said, "is if it comes back, it stays, it successfully breeds, and those kids grow up."