Day

August 8, 2019
08
Aug

Two long-scarce freshwater mammal species are staging a comeback in Bay Area waterways.

The California Department of Fish and Wildlife (CDFW) recently updated its distribution map for the state’s river otters, reflecting sightings by citizen-scientist “otter-spotters.” River Otter Ecology Project director Megan Isadore says the map fills in major gaps in the North Bay and East Bay, increasing otters’ documented range by 4,100 square miles. “It’s interesting to find how well they’re doing in very populated cities,” she says. Absent from the Bay Area for decades, river otters were observed near Tomales in 1989 and sightings have proliferated since then, possibly due to cleaner waterways. In addition to “Sutro Sam,” who frequented San Francisco’s Sutro Baths, they’ve been reported in Walnut Creek, Petaluma, and even at the Golden Gate Fields racetrack on the...
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08
Aug

A small but mighty wetlands project on the San Rafael waterfront is moving forward thanks to a $1 million planning and design grant from the San Francisco Bay Restoration Authority.

Restoration of the heavily eroded 20-acre Tiscornia Marsh at the mouth of the San Rafael Canal will use dredged sediment to create new habitat for the endangered Ridgeway’s rail and salt marsh harvest mouse, migratory shorebirds, and other marsh species. Meanwhile, improvement of an adjacent levee will enhance public access along a levee-top section of the Bay Trail and, perhaps most critically, provide flood protection for the nearby Canal District, a dense, low-income community that’s home to many Latino immigrants —and also among the Bay Area’s most vulnerable to sea-level rise. “Our project will help with that, because that section of the levee is uneven and low,” says Barbara Salzman, executive director of Marin Audubon, which owns the marsh parcel....
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08
Aug

Sea level rise combined with future coastal storms will be costlier and more destructive to California than earthquakes or wildfires.

A new study by United States Geological Survey researchers examines how future coastal storms and waves will affect California’s shoreline via erosion and flooding in conjunction with sea-level rise. And it puts numbers on the cost and people affected by California’s future storms and waves: about $150 billion in property and 600,000 people by 2100. “Bay Area communities account for two-thirds of the projected impacts across the state over the next century,” explains lead author Patrick Barnard. “Many communities, such as Foster City, are vulnerable to extreme storms today, and that vulnerability will increase dramatically over the next few decades, even with just several inches of sea-level rise.” If nothing is done to prepare the coast, sea level rise pushing...
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08
Aug

Coyote Valley, an important wildlife corridor connecting the Santa Cruz and Diablo Mountain ranges, would receive new protections under state legislation introduced in April.

AB 948 would create a new Coyote Valley Conservation Program, to be administered by the Santa Clara Open Space Authority. The bill would expand the existing protected area from 7,400 acres to 17,000 acres, and boost new efforts to preserve its resources. Coyote Valley, which drains the ecologically rich upper watershed of Coyote Creek, has long faced development threats as surrounding South Bay communities expand. The area provides critical habitat for critters large and small, which use the valley—especially its waterways—to move between more remote areas in the two mountain ranges. The Valley also includes 2,500 acres of floodplains and sits atop half of Silicon Valley’s undeveloped aquifer recharge areas, making its protection even more important. “Coyote Valley’s very shallow...
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08
Aug

Invasive clams and freshwater exports from the Delta have created dramatic and unsustainable changes in the San Francisco Estuary’s foodweb over the past 50 years.

 A study by UC Davis researchers found a 97% decline in phytoplankton, the microscopic foundation of the food chain. “Understanding the causes for the decline in the pelagic [water column] community is essential so that efficient solutions can be implemented,” says Bruce Hammock, a research scientist at the UC Davis School of Veterinary Medicine’s Aquatic Health Program. The invasive clams (Potamocorbula amurensis), originally from Asia, have been over-consuming phytoplankton and zooplankton for more than 30 years, and have long been understood to account for part of the fish population’s decline; the new study investigated the additional effects of exports. Beginning in the 1940s, fresh water from the Delta has been pumped by the federal Central Valley Project and the State...
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08
Aug

New shoreline strategies piloted in Puget Sound could help young fish in urbanized estuaries elsewhere.

When Seattle rebuilt its seawall in 2017, they hoped to make the hardened shoreline a little less daunting for the young salmon that hug it closely on their journey to the ocean. Project managers took a three-pronged approach. First, they added texture and complexity into the new concrete seawall to encourage invertebrates, food for the young fish, to settle in nooks and crannies and on horizontal “shelves” built into the wall. Mussels, ecosystem engineers, have settled on the shelves and attracted many other organisms. Next, they installed a habitat “mattress” in the seafloor in front of the wall. This horizontal structure of mesh-covered rocks lifts the seafloor, calms waves, and encourages the growth of kelp and invertebrates for the salmon....
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08
Aug

While it’s been a tough year for marine mammals along the California coast, local San Francisco Bay conditions may have afforded scientists a unique opportunity to study emerging ocean problems.

The Marine Mammal Center participated in 12 necropsies of deceased gray whales in and around the Bay. Later in the year, malnourished Guadalupe fur seals stranded along the coast at a historically high rate. In June, a surprisingly early toxic algae bloom off the coast of San Luis Obispo caused a rash of cases of Domoic Acid Toxicity among pregnant and yearling California sea lions. Dr. Cara Field, staff veterinarian at The Marine Mammal Center, has some theories as to why these events have occurred. Whale necropsies showed significant emaciation, consistent with studies done on gray whales in Mexico this past winter showing that many were already in poor body condition after returning from their summer feeding grounds in the...
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