Does knowing the History of Life in the Bay help us with its Restoration? Predicting the Future of San Francisco Bay: Learning from History Andrew Cohen Center for Research on Aquatic Bioinvasions

Reactive Reducing Damage Preservation Active Restoration

Nichols et al. 1986

Before ,000 acres ,000 acres ,000 acres Restoration target100,000 acres Tidal Saltmarsh in San Francisco Bay

Planting for saltmarsh restoration (from Zedler 1987).

Paul Amato photo

Past abundance Why we lost it Details of nature and function Eco-historical knowledge:

Olympia oyster Ostrea lurida What does Eco-history tell us?

“These oysters were really super-abundant 150 years ago," said Edwin "Ted" Grosholz, a marine ecology specialist at UC Davis. “We know that from the harvest numbers in San Francisco Bay in the late 1800s...At one time, Olympia oysters littered San Francisco Bay.” —SF Chronicle 4/28/2003 “Historically, the native oyster (Ostrea lurida), was present in the Bay in prodigious quantities.” —Skinner 1962 “Massive shell middens formerly found around the Bay indicated that aboriginal people consumed large quantities of mollusks, particularly the native oyster Ostrea lurida…Evidence of the rapid decline of shellfish resources soon after the arrival of the white man is equally striking.” —Nichols 1979

“Gold Rush settlers found the oysters irresistible and gobbled them up so fast they were just about harvested out of existence.” —Sacramento Bee 11/26/2001 “The vast reefs of the 1800s...were smothered by gold miners' silt, poisoned by raw sewage and carved up by Barbary Coast oystermen.” — SJ Mercury News 6/8/2004 “Over-harvesting and degraded water quality have depleted the native oyster (Ostrea lurida) population in San Francisco Bay, reducing a once dominant local fishery resource to a few scattered remnant populations.”—Save The Bay Summer 2001

“In the past few years, researchers…began noticing an unfamiliar species...the native oyster of the bay, seldom seen since the 19th century. Apparently—and exactly how remains a mystery—the little native oyster hung on through the hard years of mining debris and low oxygen...in the bay.” —Booker 2006 Pacific Historical Review “The native Olympia oyster...once dominated San Francisco Bay’s ecosystem …Due to over harvesting, loss of habitat, and pollution, oysters virtually disappeared from the Bay…Indications that oysters were returning to San Francisco Bay were seen in the late 1990s when small, scattered populations were discovered on docks near Redwood City.” —submission to Journal of Shellfish Research

Native Oysters in SFBay Abundant Declined Disappeared Reappeared & Rediscovered 1700s to mid-1800s over-harvesting pollution mining sediment late 1800s-1900s 1990s

Front page part Front page of the San Francisco Chronicle, Feb. 4, 1999

Presence of Native Oysters Redwood Creek to Vallejo year% of sitescommon at % of % of % of % of 122

Presence of Native Oysters # of # of yearrecordsyearrecords

Albatross Survey

Albatross dredge map Native oysters collected at 17 sites.

Native Oysters in SFBay Abundant Declined Disappeared Reappeared & Rediscovered 1700s to mid-1800s over-harvesting pollution mining sediment late 1800s-1900s late 1990s

1769Portola 1776Ayala & Anza 1834Independence 1848Gold 1850Olympia oyster imported from Washington and reared in the Bay 1869Virginia oyster imported from East Coast and reared in the Bay

SF in 1847

17941, , , , , , , , ,782 Population of San Francisco

Main Writings on the History of Oysters In California Barrett (1963) The California Oyster Industry Skinner (1962) Fish and Wildlife Resources of the San Francisco Bay Area Bonnot (1935) The California Oyster Industry Townsend (1893) Report of Observations Respecting the Oyster Resources and Oyster Fishery of the Pacific Coast of the United States Ingersoll (1881) The Oyster-Industry

Estimated Depth of Sediment (m) Deposited from Suisun Bay & Carquinez Strait0.30 San Pablo Bay0.47 Central Bay0.00 South Bay-0.05 — based on Krone (1979)

So if it wasn’t overharvesting, or pollution, or hydraulic mining debris that did in the native oysters, then what did?

West Berkeley Shellmound

SFChron-Front page.jpg from Story et al. 1966

Native Oysters in SFBay Abundant Declined Disappeared Reappeared & Rediscovered 1700s to mid-1800s over-harvesting pollution mining sediment late 1800s-1900s late 1990s