Now available: Guide to Olympia Oyster Restoration and Conservation: Environmental Conditions and Sites that Support Sustainable Populations in Central California (with site evaluations for Elkhorn Slough and San Francisco Bay)
By Mark Prado
Marin Independent Journal
Oyster beds and eelgrass off of Marin that help keep bay species healthy should be protected and expanded, according to a new report that details life beneath the waterline.
The San Francisco Bay Subtidal Habitat Goals report was developed by the state Coastal Conservancy, the National Oceanic and Atmospheric Administration, the San Francisco Bay Conservation and Development Commission and the San Francisco Estuary Partnership.
The advisory document identifies how actions could benefit sea life in the bay over the next 50 years. Researchers hope it paves the way for more study and restoration projects, leading to a healthier bay for bottom-dwelling organisms and for the salmon, herring, shorebirds, pelicans and sea lions that ride higher on the same food chain.
"We all see the bay as we drive over the bridges, but all we see is the surface," said Marilyn Latta, project manager for the report at the Coastal Conservancy. "There are many species and a lot of life that we do not see."
Among the species, eelgrass is identified as being critical. One of the strongest beds of eelgrass sits in Richardson Bay, while another patch rests off Keil Cove near Tiburon.
Eelgrass provides a nursery for many fish and shellfish species and is a major food source, forming the base of food webs and hosting organisms that feed directly on its leaves. It supports tiny plants, animals and organisms that, in turn, are eaten by other invertebrates,
larval and juvenile fish, and birds.
Eelgrass beds also slow wave and current action, trap suspended particulates and reduce erosion by stabilizing sediment. The plant improves water clarity, cycles nutrients and generates oxygen during daylight hours.
"It forms these meadows that do a lot of beneficial things for the bay," Latta said.
The report calls for the creation of eelgrass reserves and suggests a need to protect them from damage by boats, construction and dredging.
In addition to reserves at Keil Cove and Richardson Bay, the report recommends survey and restoration sites at Horseshoe Cove in Sausalito; near the Corte Madera and Muzzi marshes; the San Rafael shoreline near Point San Pedro; and west of Point San Pedro along the shoreline of China Camp State Park.
The report also calls for expanding oyster beds in the bay. The Olympia oyster, which measures no more than 1.5 inches in diameter when fully grown, once was plentiful in the bay, acting as a water purifier, as well as helping other species. Some fish, such as the goby, lay their eggs inside vacant oyster shells. For others, such as angel sharks and seabirds, the oysters make up part of their diets.
Projects at the Marin Rod and Gun Club in San Rafael and in Richardson Bay to bring back the oysters have proved fruitful.
"People and groups have done wonderful pilot projects to help the oysters come back in Marin," Latta said.
The report recommends restoring oyster beds near Dunphy Park in Sausalito; Brickyard Park in Strawberry; Angel Island; Richardson Bay; Arambaru Island in Richardson Bay; the San Rafael shoreline from the Marin Rod and Gun Club to south of the McNears Beach area; as well as the Marin Islands National Wildlife Refuge.
"The oysters are important for the bay," Latta said. "Much of the bay's bottom is soft mud; the oyster shells provide a hard surface for others critters to attach themselves to and grow."
Derelict boats that litter Marin's water and shores are also addressed in the report, which suggests funding be found to remove them. Oil and paint from the boats sully the bay's waters and those that sink smother the bottom.
The report--which cost about $800,000 to produce--is the second of three addressing the bay. The first dealt with wetlands, and the next will focus on habitat just above the water line along land.
"We now have specific recommendations to protect and enhance subtidal habitat throughout San Francisco Bay," said Patrick Rutten, an NOAA restoration official.
By Mike Taugher
A new blueprint for the hidden world beneath San Francisco Bay's shimmering waters calls for thousands of acres of oyster beds and eelgrass, beach replenishment projects and research.
The report, a four-year study by state and federal agencies, is a follow-up to an influential 1999 blueprint that paved the way for a major acceleration of wetlands restoration around the bay, now the largest wetlands restoration program on the West Coast.
Thursday's Subtidal Habitat report is less specific than the earlier Baylands Habitat Goals report because less is known about the ecosystem hidden underwater.
But researchers hope it paves the way for more study and restoration projects over the next 50 years, leading to a healthier bay for bottom-dwelling organisms and for the salmon, herring, shorebirds, pelicans and sea lions that ride higher on the same food chain.
It contains no cost estimate, mostly because many of the initiatives have not been tried on a large scale. The report suggests trying small projects, such as oyster bed restoration and pilings removal before moving on to larger projects.
No one knows the extent of the bay's oyster beds, mostly because the water's murkiness makes it difficult to see exactly where they are and how far they spread.
But the bay's native Olympia oysters continue to survive and the bay has several hundred thousand tons of fossilized oyster shells, said Marilyn Latta, project manager for the report at the State Coastal Conservancy.
The report calls for expanding oyster beds to 8,000 acres, nearly half of which could be off Contra Costa's shore between Point San Pablo and Point Pinole.
Could that support commercial oyster farming?
"That would be a great dream far off in the future," said Latta. "It is not at all related to our planning now, though. It would not be healthy for people to eat them now."
Because they are filter-feeders, oysters would absorb too many pollutants, including mercury, selenium, hydrocarbons, PCBs, pharmaceuticals and other toxic materials, Latta said.
The report also calls for tripling the area of the bay's eelgrass beds from 4,000 acres to 12,000 acres.
More eelgrass would mean more places for herring, for example, to lay eggs. The biggest eelgrass bed containing more than one-third of the bay's growth is near Richmond.
"It forms these meadows that do a lot of beneficial things for the bay," Latta said.
The report suggests creating eelgrass reserves but does not say what kinds of restrictions might be needed to protect them from damage by boats, construction or dredging. Latta said it was beyond the report's scope to recommend specific eelgrass reserves.
Some of the areas suggested include Point San Pablo, Crown Beach, Richardson Bay and Coyote Point.
The report also suggests using clean sand from maintenance dredging to build up beaches at Eastshore State Park, Point Isabella Regional Shoreline, San Rafael Shoreline and others.
As a result of the 1999 wetlands report, the amount of wetlands, or baylands, ringing San Francisco Bay has increased. There were about 40,000 acres of wetlands at the time of the report, and nearly that much has either been restored or is on the way to being restored. The earlier report set a goal of 100,000 acres total acres.
"The acquisition and protection of shoreline properties has been greatly advanced by the publishing of the habitat goals report because it brought a strong scientific consensus of needs and how to do it," said David Lewis, executive director of Save the Bay, an environmental group.
A third report on the Bay Area's upland habitat, which will include the nine Bay Area counties, is nearing completion, Latta said.
The report released Thursday, San Francisco Bay Subtidal Habitat Goals Report, was developed by the State Coastal Conservancy, the National Marine Fisheries Service, the San Francisco Bay Conservation and Development Commission and the San Francisco Estuary Partnership. It was expected to be available Thursday at http://www.sfbaysubtidal.org.
January 27, 2010
Click here to listen to the Subtidal Habitat Goals podcast with Project Manager Marilyn Latta, as part of the San Francisco Bay Joint Venture "Your Wetlands" podcast series.
Ariel Rubissow-Oakamoto's Bay Nature article describes the Subtidal Habitat Goals Project.