A USGS staff member collecting data
in the salt marshes of San Francisco Bay.
(photo USGS/K. Thorne)
By Paul Rogers
San Jose Mercury News (MCT)
Five years into the first significant construction to restore thousands of acres of former industrial salt ponds around San Francisco Bay back to wetlands, dozens of species of fish and birds — from herring and anchovies to pintail ducks — are expanding their range across the bay, with some clearly growing in population.
That was among the key conclusions from scientists at a recent conference held at the U.S. Geological Survey in Menlo Park, Calif., to assess the status of the massive salt pond project.
"So far, so good," said Jim Hobbs, a fisheries biologist with University of California, Davis.
In 2003, Cargill Salt, based in Newark, Calif., sold 16,500 acres of its salt ponds for $100 million to the state Department of Fish and Game and the U.S. Fish and Wildlife Service. The ponds, which cover roughly 20 miles of California shoreline from Hayward to Alviso to Redwood City, were used to make salt for roads, medicine and food as far back as the 1800s.
The purchase set in motion the largest wetlands restoration on the West Coast, an undertaking that has been compared to the restoration of the Florida Everglades or Chesapeake Bay. The project could take 40 years and $1 billion to complete, not only to bring back fish, birds and other wildlife, such as harbor seals, but also to provide public overlooks, boat launches and walkways. Also costly is installing stronger flood protection on the aging levees near bay-front communities.
FISH EXPANDING HABITAT
Most of the former salt ponds' levees have been fitted with tidal gates, and several have been breached during the past five years, allowing bay waters to flood in and replace hard salt crusts and highly salty water.
Hobbs studied four former Cargill salt ponds last July through December. Three off Milpitas were breached in 2006. The other one, north of Sunnyvale, was breached last year. Together they total 880 acres.
Hobbs found 30 species of fish in the ponds, the same number he found in the open bay.
They included northern anchovy, goby, longfin smelt, Pacific herring and spined stickleback. He said the findings are encouraging because they show that fish have accepted the ponds as habitat, despite their formerly salty pasts. More fish could eventually mean more animals that eat the fish, from birds to harbor seals.
A similar study done in 1,400 acres of former Cargill ponds in the North Bay near the Napa River also found a wide abundance of bay fish had come back, including striped bass, tule perch and even a chinook salmon, some only weeks after the ponds had been breached.
"If you build it, they will come," said Francesca Demgen, a biologist with URS Corp., a San Francisco engineering firm working on the project with government biologists.
Scientists are finding similar trends with birds.
Between 2002 and 2010, the number of dabbling ducks, which include pintail, northern shoveler and other species, increased from roughly five per 2.4 acres to 12 per 2.4 acres in 23 former salt ponds around Alviso. Arriana Brand, a wildlife biologist with the U.S. Geological Survey who conducted the study, also found that medium-size shorebirds, including willets, stilts and godwits, doubled in number in the Alviso ponds over the same time, while smaller shorebirds, such as sandpipers, nearly doubled. Some species, such as diving ducks, have not seen increases.
As more research is completed, difficult choices will have to be made over the next 20 years, said John Bourgeois, executive project manager for the South Bay Salt Pond Restoration Project, overseen by the California Coastal Conservancy.
Scientists will have to decide how much of the acreage to convert to tidal marsh —which helps some species like clapper rails, but hurts others like snowy plovers — and how much to leave as open ponds.
"In this first wave of restoration we're seeing positive results," he said. "But this is a dynamic landscape. By restoring ponds, some species are going to benefit and some aren't."
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