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

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Before 1850 190,000 acres

1979 31,000 acres

2000 40,000 acres

Restoration target 100,000 acres

Tidal Saltmarsh in San Francisco Bay

Planting for saltmarsh restoration (from Zedler 1987).

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• 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

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Presence of Native Oysters Redwood Creek to Vallejo

year % of sites common at

1993 57% of 14 1

1994 77% of 13 1

1996 79% of 14 1

1997 75% of 12 2

Presence of Native Oysters 1951-1979

# of # of

year records year records

1951 3 1974 7

1962 2 1975 7

1963 2 1976 4

1964 2 1977 1

1970 5 1978 4

1971 1 1979 4

1973 4

Albatross Survey 1912-13

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

1769 Portola

1776 Ayala & Anza

1834 Independence

1848 Gold

1850 Olympia oyster imported from Washington and reared in the Bay

1869 Virginia oyster imported from East Coast and reared in the Bay

SF in 1847

1794 1,056 1798 833 1800 867 1815 1,488 1830 350 1842 196 1844 50 1846 200 1847 459 1848 850 1849 5,000 1850 21,000 1860 56,802 1870 149,473 1880 233,959 1890 298,997 1900 342,782

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 1870-1896

Suisun Bay & Carquinez Strait 0.30

San Pablo Bay 0.47

Central Bay 0.00

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