ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
A Preliminary Assessment of the Economic Impact
of Water Pollution on the Shellfish Resources
of San Francisco Bay, California
Prepared by
Review & Evaluation Section
Division of Field Investigations - Denver Center
Denver, Colorado
July 1971
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Section
TABLE OF CONTENTS
Introduction . .
Summary and Conclusions . . . . .
Description of Area
Page
6
Water Quality Problems
Dissolved Oxygen
Bacterial Contamination
Toxic Materials
Contamination of Aquatic Life
Biostimulants and Algal Populations
Sediments . .
Sources of Pollution .
t4unicipal Waste Sources
tndustrial Waste Sources
Combined Sewer Overflows
Vessel Pollution .
Dredging
Urban Runoff .
Agricultural Drainage
Natural Runoff
Oyster Fishery
History
Present Status .
Potential Development
Clam Fishery
History
Present Status
Potential Development
Economic Impacts . . . .
Interstate Aspects . . .
. S S S S
S S
21
21
30
. . 34
34
. . . . . . . . S 5 35
35
36
. . . . . . . . . . 36
• • . 37
• . . 38
• . . 38
• . . 40
41
• . 42
42
• 43
• . 43
• 44
49
References . . • . • • . .
Listof Figures
Listof Tables
SO
1 1 1
1
3
Applicable Water Quality Regulations
Federal Water Pollution Control Act
Water Quality Standards
The Rivers and Harbors Act of 1899
9
9
10
11
• 16
• S S S S 17
18
18
19
• . . • • 20
20
S
• S S
• S S
Impact of Pollution on the Sheilfishing
S S S
S S S S
Indus
S • S
• S S
S S S
try
• S
S S
I
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LIST OF FIGURES
Figure Description Follows Page
1 San Francisco Bay System 6
2 Water Quality Zones 11
3 Locations of Municipal Waste Sources 29
4 Location of Oyster Beds in 1890 38
1 1
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LIST OF TABLES
Table Description Page
1 Beneficial Uses to be Protected 12
in San Francisco Bay
2 Water Quality Standards Applicable to 13
the San Francisco Bay System
3 Municipal Waste Sources 22
4 Summary of Municipal and Industrial 31
Waste Sources - 1965
5 Summary of STORET Inventory of Municipal 31
and Industrial Waste Sources
6 Industrial Waste Sources 32
7 Summary of Oyster Harvest 46
San Francisco Fishing Region
8 Summary of California Oyster Harvest 47
:iii
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1
INTRODUCTION
San Francisco Bay and adjoining bays form the largest estuarine system
in California. The San Francisco metropolitan area and adjacent urban areas
surrounding the Bay system, with a population of more than six million, form
the second largest population center in California. Large industrial com-
plexes are also located in close proximity to the ay system. The Bay is
a major international port.
Pollution from municipal and industrial waste sources, urban runoff,
vessel wastes and agricultural drainage have degraded water quality through-
out the estuary. Although water quality has improved in recent years as the
result of improved waste disposal practices, water quality is still substan-
tially degraded and violations of water quality regulations and impairment
of water uses presently occur.
The estuary historically supported a major commercial fishery. As
early as 1870, pollution caused some impairment of this water use, especially
commercial sheilfishing. Although a large commercial fishing industry still
operates in the San Francisco area, pollution has contributed to a decline
in the annual harvest of seafood directly from the estuarine system and has
essentially eliminated the commercial harvest of shellfish. Oysters and clams
are still present in the estuary in substantial numbers but bacterial contami-
nation prevents their harvest for human consumption.
This paper summarizes water quality conditions existing in the San Fran-
cisco Bay system and lists principal sources of pollution. Water quality reg-
ulations applicable to abatement.of present pollution are also summarized.
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The history of the commercial shellfish industry is discussed and the eco-
nomic impact of pollution on this industry evaluated. In short, this paper
presents background information from which an assessment can be made to de-
terrnine if the conditions precedent to calling an Enforcement Conference
pursuant to the provisions of the Federal Water Pollution Control Act exist
with respect to the San Francisco Bay system.
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SUMMARY AND CONCLUSIONS
I. Water quality degradation in San Francisco Bay and adjoining estuarine
waters impairs beneficial water uses including water contact recrea-
tion, fish and wildlife propagation and shellfish harvesting.
2. The San Francisco Bay system is a navigable coastal water. Pollution
of the Bay system is subject to abatement under the provisions of the
Federal Water Pollution Control Act, as amended.
3. Discharges of industrial wastes to the Bay system are subject to the
requirements of the Rivers and Harbors Act of 1899.
4. Low dissolved oxygen levels at several locations in the Bay and tidal
tributaries have caused depletion or elimination of aquatic life popu-
lations.
5. Bacterial concentrations in much of the Bay system exceed allowable
limits for water contact sports and she llfishing. In spite of this
health hazard, recreational and sport shellfishing continues.
6. A number of fish kills have resulted from spills or discharges of toxic
materials. In addition to acute toxicity problems, chronic toxic effects
are also present. Pesticide concentrations exceed recommended limits.
7. Shellfish and other aquatic life are contaminated by noxious chemicals
and taste and odor producing substances in addition to bacterial contami-
nation.
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8. Nutrient concentrations are above desirable limits and nuisance aquatic
growths are present in several locations.
9. About 400 million gallons per day of municipal wastes are discharged
to the Bay system by 66 treatment facilities serving a population of
more than four million and numerous industries. About half the flow
volume is treated in 25 plants which provide only primary treatment.
Much of the wastes discharged do not receive chlorination or adequate
disinfection. Municipal wastes are a major source of oxygen demanding
materials.
10. Only limited information is available on industrial wastes discharged
directly to the Bay system. Their volume is probably about one-tenth
of the municipal waste discharges but may have a proportionally greater
water quality impact due to its constituents. Industrial waste dis-
charges are known to be sources of toxic materials and taste and odor
producing substances.
11. Prior to 1900 the San Francisco Bay system supported a major shellfish
industry. During the 1890’s, the oyster fishery was the single most
valuable fishery in California. Commercial oyster culture was a
million dollar business. A number of factors of which pollution was
the most important caused the rapid decline of the shellfish industry
after 1900. Today, the industry is essentially non-existent.
12. Water quality conditions, including bacterial contamination, are the
major factor preventing the reestablishment of a shellfish industry in
San Francisco Bay. South San Francisco Bay ts potentially the best
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oyster producing area in California.
13. It is estimated that the economic impact on the regional economy pro-
duced by the elimination of the oyster industry by pollution of San
Francisco Bay is in the range of $820,000 to $4,000,000 annually.
The elimination of the clam and mussel fishery produces art addition-
al economic impact.
14. Pollution of San Francisco Bay affects the interstate shipment of oysters
into California for marketing in the Bay area, blocks the interstate ship-
ment of seed oysters for use in oyster culture in the Bay, and prevents
development of potential oyster production which could create a surplus
supply for interstate shipment to other areas.
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DESCRIPTION OF AREA
The San Francisco Bay system includes San Francisco Bay, San Pablo
Bay, and Suisun Bay, and extends from the eastern end of Chipps Island at
the City of Pittsburg, where the Sacramento and San Joaquin Rivers join,
westward and southward to the mouth of Coyote Creek near the City of San
Jose, a distance of approximately 85 miles. The Golden Gate is about half-
way between San Jose and Antioch and is the Bay’s only connection with the
ocean. The San Francisco Bay system is illustrated in Figure 1.
The normal annual precipitation over the San Francisco Bay system
and its local drainage areas amounts to 19 inches per year. Over the entire
Bay system the mean annual evaporation is almost 48 inches, more than twice
the annual precipitation. The difference between precipitation and evapora-
tion accounts for the loss of more than 650,000 acre-feet of water each
year from the water surfaces alone.
While the Sacramento and San Joaquin Rivers contribute the greatest in-
flow to the Bay (seventeen million acre-feet annually), eight smaller streams
also discharge to the Bay system. The combined mean annual discharge of
these local streams is only 435,000 acre-feet per year, and for this reason
most of the cities around the Bay of necessity have developed or depend
upon water sources outside the Bay system.
One hundred years ago the area of San Francisco Bay was nearly 700
square miles including more than 300 square miles of marsh land. Almost
80 percent of this marsh land has been reclaimed, chiefly for agricultural
use and salt ponds. Now, the area of the Bay at mean tide is approximately
435 square miles.
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N A PA
P TALU H A
SAN 0
RAFAEL
PACIFIC
OCEAN
) 5 10
E— -+-----:=
SCALE Iii MILES
VAIL E JO
RODEO
BRIDGE
,APU.AND-SAN FRANCISCO BAY BRIDGE
° OAKLAND
SAN JOSE
0
PIT TS B U RG
ANT IOC I
I
BRIDGE
Figure 1 San Francisco Bay System
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The total water volume at mean tide in the San Francisco Bay system
is approximately 235 billion cubic feet, or more than one and one-half
cubic miles of water. The tidal prism, or the volume between high and
low tides, is about 50 billion cubic feet or 21 percent of the average
total volume of water in the Bay. Fifteen to 20 percent of this tidal
prism is replaced by new ocean water during each tidal cycle. This is the
principal mechanism which p2llutants are ultimately removed from the p y.
Much of the Bay is very shallow, the average depth being only 20 feet.
The shallowness of the Bay has a number of important consequences. Wind-
generated waves disturb the bottom and contribute substantially to the high
turbidity of the water. Again, the shallowness is an important factor in
determining the relative importance of surface reaeration and overall oxy-
gen balance of the Bay.
Nine counties, with a total population of more than six million, are
located adjacent to the Bay system. These counties are Alameda , Contra
Costa, Mann, Napa, San Francisco, San Nateo, Santa Clara, Sonoma, and
Solano. Three major cities, San Francisco, Oakland and San Jose, as well
as many smaller cities, are located in the Bay area. Topographical features
are such that much of the urban development is located in close proximity to
Bay shorelines.
The geographical features of the area have led to its development as
one of the world’s leading ports of commerce. The Bay area, with its ex-
cellent harbor facilities and thorough accessibility by ship, has developed
large industries in food products, paper, metal, petroleum and textiles.
There are extensive agricultural lands in the vicinity and in the nearby
Central Valley which produce fruit, vegetables, dairy products, grains and
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vine. Salt and cement products are produced in large quantities directly
from the Bay. The geographical setting has also made the area a strategic
location for military bases and shipyards.
Commercial fisheries which obtain seafood products directly from the
Bay system and from the nearby Pacific Ocean are also a significant indus-
trial enterprise in the Bay area. The relative importance of the seafood
industry in the San Francisco area with respect to the total California
seafood industry has declined in recent years. This decline is due to the
combination of the increased development of fisheries in other parts of the
State and a reduction in the seafood harvest in the Bay area due to pollu-
tion and other factors.
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APPLICABLE WATER QUALITY REGULATIONS
San Francisco Bay is a navigable water which is also a coastal water
subject to the ebb and flow of the tide. The Bay and adjacent waters are
contained entirely within the State of California and are therefore intra-
state waters. Several provisions of the Federal Water Pollution Control
Act are applicable to pollution of intrastate coastal waters. Water qual-
ity standards applicable to the Bay system have been established by the
State and approved as Federal standards pursuant to the provisions of the
Water Quality Act of 1965. The Rivers and Harbors Act of 1899 is appli-
cable to discharges of industrial wastes to navigable waters. These
water quality regulations are discussed below.
Federal Water Pollution Control Act
Section 10(a) of the Federal Water Pollution Control Act, as amended,
(33 U.S.C. 466 et. seq.) provides that “the pollution of interstate or
navigable waters in or adjacent to any state.. .which endangers the health
or welfare of any persons, shall be subject to abatement as provided in
this Act”.
Since San Francisco Bay is navigable, pollution of the Bay is subject
to abatement under the provisions of the Act. One step in securing such
abatement is the calling of a Federal-State Enforcement Conference. Section
10(d) provides the following basis for calling such a conference:
“The Secretary shall also call such a conference whenever, on the
basis of reports, surveys, or studies, he has reason to believe
that any pollution referred to in subsection (a)...is occurring,
or he finds that substantial economic injury results from the in-
ability to market shellfish or shellfish products in interstate
commerce because of pollution referred to in subsection (a) and
action of Federal, state, or local authoricies.’ 1
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The “Secretary” referred to above was the Secretary of the Interior.
Administration of the provisions of the Act, formerly assigned to the
Secretary, is assigned to the Administrator of the Environmental Protec-
tion Agency.
As discussed in following sections, pollution of San Francisco Bay is
preventing the marketing of shellfish in interstate commerce with attendant
substantial economic injury. Sheilfishing areas in the Bay have been
closed to shellfish harvesting by State authorities because of such pollu-
tion. The requirements for calling a Federal-State Enforcement Conference
are thus met.
Federal rules regulating the discharge of oil to navigable waters
were established on September 11, 1970, pursuant to the provisions of Sec-
tion 1l(b)(3) of the Act, as amended by the Water Quality Improvement Act
of 1970. These rules prohibit discharges of oil to navigable waters from
any source which:
“(a) Violate applicable water quality standards, or
(b) Cause a film or sheen upon or discoloration of the surface
of the water or adjoining shorelines or cause a sludge or
emulsion to be deposited beneath the surface of the water
or upon adjoining shorelines”.
All discharges of oil to the San Francisco Bay system are subject to the
provisions of these regulations.
Water Quality Standards
Water quality standards have been established for the San Francisco
Bay system by the State of California and approved as Federal standards
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in accordance with provisions of the Federal Water Pollution Control Act,
as amended. A complete set of current standards was not immediately
available to DFI-DC. The following discussion is based on the standards
originally submitted for Federal approval but subsequently revised.
The waters of the Bay system have been divided into seven water
quality zones. 1 ’ These zones are shown in Figure 2.
The water quality standards specify various beneficial water uses
which are to be protected in the San Francisco Bay system. 1 ’ These uses
are listed in Table I by water quality zone.
Water quality criteria which specify numerical and/or narrative
limits for various parameters were established for each beneficial water
use to be protected. The most restrictive numerical limit or narrative
criterion for each parameter is listed in Table 2.
The Rivers and Harbors Act of 1899
The Rivers and Harbors Act of 1899 prohibits the discharge of indus-
trial wastes to navigable waters without a permit from the U. S. Army
Corps of Engineers. Section 407 of the Act, referred to as the Refuse Act
of 1899, makes it unlawful to discharge from any “...manufacturing estab-
lishment, or mill of any kind, any refuse matter of any kind or description
whatever other than that flowing from streets and sewers and passing there-
from in a liquid state, into any navigable water from which the same shall
float or be washed into such navigable water...” provided that a discharge
may be permitted under certain conditions specified by the Corps of Engin-
eers.
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I0
SCALE IN MILES
. VALLEJO
I
MART
BRIDGE
SR
OAKLAND-SAN FRANCISCO BAY BRIDGE
I OAKLAND
SAN MATED •
SAN MATEO-HAYWARD BRIDGE
MILPITAS
Figure 2.
Water Quality Zones
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Table 1. Beneficial Uses to be Protected in San Francisco Bay
Industrial Supply:
Uses
Water Oualitv Zone
12
1 2 3_ 4 5 6 7
boiler X
cooling X X X X X X X
rinsing X X X X X X X
processing X X X X X X X
1/
Agricultural Supply:
irrigation
x
Fish and Wildlife Propagation and
Aquatic Growth:
fish habitat, migration, spawning X X
shrimp and crab habitat . . . . . X X
shellfish habitat X X
waterfowl habitat X X
mammal rookery . X X
Commercial Fishing and Sheilfishing . . X X
Recreation:
swimming, waterskiing, skindiving,
picnicking ... X X
pleasure boating X X
fishing . . . X X
shelifishing X X
hunting. X X
Enjoyment of Esthetic Values X X
Navigation X X
x x x K K
x K K K K
K K K K K
K K K K X
K K K
K K K K K
K K K K K
K K K K K
K K K K K
K K K K K
K K K K
K K K K K
K ‘K K K X
Some seasonally.
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Table 2.
WATER QUALITY STANDARDS
Applicable to the San Francisco Bay System
Parameter Standard
pH 7.0 - 8.6
Temperature Shall not be significantly increased
above natural nor altered to ad-
versely affe..t aquatic life.
(This standard not Federally approved.)
Dissolved Oxygen 5.0 mg/i
(minimum allowable concentra- (except when natural conditions cause
don) lower concentrations)
Coliform Organisms Median shall not exceed 70 coliform
organisms per 100 milliliter in any
sample, nor shall more than 10 percent
of the samples collected in any month
exceed 230 per 100 milliliters.
Radioactivity Shall not exceed 1/10 of the MPCW values
(maximum allowable) given for continuous occupational
exposure in “National Bureau of Stan-
dards Handbook 69”.
Turbidity Shall not be significantly increased
(maximum allowable) (JCU) above natural background levels,
nor to a degree which adversely
affects aquatic life.
Color Free from substances.attributable to
wastes that produce detrimental color.
Taste and Odor No organic or inorganic substances
which impart undesirable tastes or
odors to species of commercial or
sport importance.
Solids Floating and settleahie solids shall
not be discharged or left along the
shoreline; (shall be) less than the
concentration of seitleable solids
that would change the physical nature
of the stream bottom or adversely af-
fect the aquatic environment.
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Table 2 (cont’d)
WATER QUALITY STANDARDS
Applicable to the San Francisco Bay System
Parameter Standard
Toxic Substances No organic or inorganic substances in
(maximum allowable) concentrations which are toxic or
detrimental to human, animal, plant,
or aquatic life.
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Executive Order No. 11574, signed by President Nixon on December 23,
1970, tightens enforcement of the Refuse Act of 1899 by requiring that
all sources of industrial wastes discharging to navigable waters or their
tributaries must apply to the Corps of Engineers for permits to continue
such discharges by July 1, 1971. This deadline was later extended to
October 1, 1971, for certain application data. Permit applications are
currently being processed cooperatively by the Corps of Engineers and EPA.
All sources of industrial wastes discharging directly to the Bay system
will be required to apply f or such permits. Application data will pro-
vide a detailed inventory of industrial waste discharges.
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WATER QUALITY PROBLEMS
The San Francisco Bay system has been polluted to some degree since
1848, when the California gold rush caused a sharp increase in population
in the Bay area. By 1900, pollution had become severe enough to cause a
decline in the productivity of the Bay fishery. Improved treatment for
various municipal and industrial waste sources has resulted in improved
water quality conditions in some areas of the Bay system in recent years,
but this improvement has been largely offset by population increases and
industrial development.
Water quality data on the Bay system immediately available to DFI-DC
are extremely limited. Much of the past Federal-State water quality study
and surveillance activities in this area were directed toward evaluating
the impact of agricultural drainage and water resource development in the
Central Valley on water quality in the Sacramento-San Joaquin Delta in the
upper portion of the Bay system, and did not provide information on water
quality conditions in the greater Bay system. As late as 1962, the State
maintained only five water quality sampling points in the Bay area, all on
tributary streams above the Bay system except a station on Carquinez Straits,
which recorded only water temperature and conductivity. Retrieval of all
data in the STORET system produced only a few pieces of data, of limited
value. Due to this lack of data, it is not possible to define present
water quality conditions with respect to specific parameters or to evaluate
compliance with water quality standards.
Variws reports are available, however, which describe water quality
conditions in general terms and outline the most serious pollution
I
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problems i f ’ V 1 J ’ t 1• These reports form the basis for the following
discussion.
Dissolved Oxygen
Throughout most of the San Francisco Bay system, dissolved oxygen con-
centrations are consistently above 80 percent of saturation; however, sig-
nificant dissolved oxygen depletions occur in several critical areas of the
Bay. The most serious dissolved oxygen deficits occur in the southernmost
part of San Francisco Bay below Durnbarton Bridge and in Coyote Creek down-
stream from the discharge of the San Jose waste treatment plant, where dis-
solved oxygen concentrations often fall to zero in the late summer at the
height of the canning season ) 1 Similar water quality problems are observed
in the sloughs receiving waste effluents along the west side of San Fran-
cisco Bay between San Jose and San Francisco, and the Napa and Petaluma
estuaries.
The low dissolved oxygen levels have resulted in the elimination or
reduction of fish and other aquatic life populations in several areas of
the Bay, especially the south Bay. In some of the most degraded areas,
fish are not present. 2 1 Some of this depletion of aquatic life may be due
to toxic materials, as discussed below, as well as dissolved oxygen depletions.
The primary factor contributing to dissolved oxygen depletions is the
discharge of organic materials from municipal waste sources. These dis-
charges are the most damaging during the canning season, when a number of
plants receive large loads of organic waste materials from food processing
plants.
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Bacterial Contamination
Studies conducted in San Francisco Bay between 1959 and 1964, and in
1968, show that coliform bacteria levels exceeded water quality standards
for water contact sports in most parts of the Bay system. ]JSuch high bacteria
levels would pose a health hazard to sport sheilfishing and would exceed al-
lowable limits for commercial harvesting of shellfish. About 90 percent of
the areas supporting harvestable populations of shellfish have been declared
unsafe for harvesting of shellfish for human consumption. 2 ’
En spite of the known bacterial contamination of the Bay system, exten-
sive recreation use such as boating, water skiing and swimming is made of
various areas of the Bay. Some sport fishing for clams also takes place.
The principal sources of bacterial contamination are domestic wastewater
discharges. Watercraft wastes, urban runoff, and combined sewer overflows
also contribute to this pollution.
Toxic Materials
A serious problem exists in the Bay system as the result of the presence
of various toxic materials. Periodic and widespread fish kills have occurred
in various portions of the Bay. In the five years between 1963 and 1968,
the California Department of Fish and Game investigated 31 reported fish kills
in the Bay system and adjacent delta)- 1 Eleven of the 31 fish kills were
identified with wastewater discharges or spills. Causes of the remaining
incidents have not been explained. Evaluation of the toxicity of municipal
and industrial waste waters has shown that almost all of these wastes are
toxic in varying degrees to fish. Oil refineries, shipping, and certain com-
munities in South San Francisco Bay have been the most common offenders with
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respect to discharges of acute toxic pollution.
Mysterious annual die-off s of thousands of striped bass, an important
commercial and sport fishing species, have occurred in the Bay. These fish
kills have not been traced to specific pollution sources; however, a life
history of’this species does not indicate that this is a normal occurrence.
Pesticide concentrations in the Bay system are also of concern.
Chlorinated hydrocarbon concentrations in most areas of the Bay exceed the
maximum concentration recommended by the National Technical Advisory Com-
mittee on Water Quality Criteria. 1 ’ Although present concentrations of chlori-
nated hydrocarbons in aquatic organisms are less than those found to be lethal to
theorganisms in most cases, the concentrations are high enough to warrant con-
cern about sublethal damage to the organisms.
Contamination of Aquatic Life
In addition to the contamination of shellfish by bacterial pollution,
as discussed above, both shellfish and other aquatic life have been contami-
nated by noxious chemicals which render them unsafe for human consumption.
In many cases, this contamination does not kill or damage the aquatic organ-
ism, but rather, poses a health hazard if consumed by humans. Domestic
sewage and phenolic wastes from oil refineries are the usual sources of con-
tamination.V Shellfish are more commonly affected, although there is some
evidence that fishes are also affected.
No information was available on hydrocarbon residues in shellfish. The
presence of industrial waste discharges from oil refineries and the usual oil
spills from commercial shipping would indicate the probability that such hydro-
carbon residues are present in shellfish.
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Biostimulants and Algal Populations
The San Francisco Bay system exhibits evidence of enrichment at various
locations, mainly along the shores and in tidal reaches of some tributaries.
Nitrogen and phosphorus concentrations in the waters of the Bay system are
substantially higher than levels where either nitrogen or phosphorus might
be growth-licniting.1” Decaying of aquatic vegetation has produced hydrogen
sulfide odors and caused blackening of lead-based paints. Mats of these
plants have reached nuisance proportions in the Albany Tide Flats. Dis-
coloration of Bay waters due to green algae and the red-pigmented marine ciliate,
mesodinium has raised concern among fishermen and shore-side property owners.
Agricultural drainage from the Central Valley, entering the Bay system
through the Delta, is one main source of nitrogen and phosphorus. Municipal
and industrial waste discharges also contribute substantial nutrient loads
to the Bay.
Sediments
Much of the Bay’s bottom is covered with fine sediments and mud. Large
sediment loads are carried into the Bay system in tributary inflow. Spoil
disposal from various dredging activities results in the movement of sedi-
ment loads into various parts of the Bay system. In the shallower portions
of the Bay, wind and wave action can stir up bottom sediments. As a result,
much of the Bay system exhibits high turbidity levels at various times. This
high turbidity has a detrimental effect on aquatic life production. As sedi-
ments settle out, they may blanket the bottom and smother aquatic life. High
turbidity and sediment concentrations were believed to be one factor contri-
butory to the decline of the Bay system’s shellfish populations.
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SOURCES OF POLLUTION
The principal source of pollution in the San Francisco Bay system is
the large population located adjacent to Bay waters. Most of the pollution
from this source enters waters as municipal waste discharges. Combined
sewer overflows and urban runoff also contribute some pollution.
Industrial developments also account for significant pollution loads,
especially toxic materials. An unknown but major industrial waste load is
discharged to municipal treatment systems.
All of the residual pollution from the Central Valley, including agri-
cultural drainage containing pesticides and nutrients, enters the San Fran-
cisco Bay system by way of the San Joaquin - Sacramento River Delta. Com-
mercial shipping and pleasure boating contribute vessel pollution. Dredging
to maintain navigation channels and for construction of shoreside facilities
redistributes pollutants in the vicinity of dredging and spoil disposal areas.
The relative magnitude of these various pollution sources is discussed below.
Municipal Waste Sources
A total of more than 400 million gallons of treated wastes are discharged
to the Bay system daily by 66 major publicly-operated treatment facilities.
These facilities primarily treat municipal wastes, but the volume of industrial
waste treated by a number of plants is also believed to be significant. Basic
information on these municipal facilities is contained in Table 3. Plant
locatLons are shown in Figure 3.
Basic data on the municipal sources listed in Table 3 were obtained
from the STORET municipal inventory. The current validity of the data is
unknown, as the dace when each source was last reviewed was unavailable. T
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Table 3. Municipal Waste Sources
Map
Key
Source
1 East Bay Municipal
Utilities District
2 City of San Leandro
3 Oro Loma Sanitary
District
4 City of ILayward
5 Union Sanitary District
Alvarado Plant
6 Union Sanitary District
Newark Plant
7 Union Sanitary District
Irvington Plant
Population
Served
608,000
50,000
185,000
97,500
21,000
62,000
64,000
Flow
MCD
ALAMEDA COUNTY
74.0
7.6
11.9
9.4
1.2
2.8
5.1
Type
Treatment
Primary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Receiving
Water
Central San Francisco Bay
South San Francisco Bay
South San Francisco Bay
South San Francisco Bay
Alameda Creek to
South San Francisco Bay
Newark Slough to
South San Francisco Bay
Mud Slough to
South San Francisco Bay
SANTA CLARA COUNTY
8 Nilpitas Sanitary
District (2 plants)
9 City of San Jose
Coyote Creek to
South San Francisco Bay
Coyote Slough to
South San Francisco Bay
31+,000
2.8
Secondary
700,000
67.4
Secondary
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Table 3. Municipal Waste Sources (cont’d)
iMi NATEO COUNTY
Artesian Slough to Coyote Creek
to South San Francisco Bay
Guadalupe Slough to
South San Francisco Bay
South San Francisco Bay
South San Francisco Bay
South San Francisco Bay
South San Francisco Bay
! est Point Slough
to South San Francisco Bay
Redwood Creek
to South San Francisco Bay
S teinburger Slough
to South San Francisco Bay
South San Francisco Bay
Map
Key
Source
Population
Served
Type
Treatment
Receiving
Water
Flow
MGD
0.3
12.5
5.5
1.7
10.8
10
City of Alviso
1,200
Secondary
1]
City of Sunnyvale
100,000
Secondary
12
Moffet Naval Air Station
---
Primary
13
City of Mountain View
55,000
Primary
14
City of Los Altos
27,500
Primary
15
City of Palo Alto
89,600
Secondary
16
Menlo Park
Sanitary District
55,000
5.0
Secondary
17
City of Redwood City
74,000
8.5
Secondary
18
San Carlos - Belmont
50,000
5.0
Secondary
19
Estero 1 unicipa1
Improvement Dis trict
10,000
0.6
Primary
20
City of San Mateo
90,000 8.8 Primary
South San Francisco Bay
-------
Table 3. Municipal Waste Sources (coflttd)
Map Population Flow Receiving
Key Source Served MGD Treatment Water
21 City of Burlingame 34,000 Tertiary South San Francisco Bay
22 City of Millbrae 22,000 1.8 Secondary South San Francisco Bay
23 San Francisco
International Airport Primary South San Francisco Bay
24 South San Francisco 83,000 9.5 Secondary
San Bruno Plant
25 Guadalupe Valley 5,000 0.1 Primary South San Francisco Bay
Municipal improve-
ment District
SAN FRANCISCO COUNTY
26 San Francisco Municipal 160,000 18.5 Primary South San Francisco Bay
Sewage System -
Southeast Plant
27 San Francisco Municipal 370,000 56.0 Primary San Francisco Bay
Sewage System -
North Point Plant
28 Treasure Island Secondary San Francisco Bay
U. S. Navy
M
-------
Table 3. Municipal Waste Sources (cont’d)
Map Population Flow Receiving
Source Served MGD Treatment Water
MARIN COUNTY
29 Sausalil:o - Mann 13,000 1.8 Primary San Francisco Bay
City Sanitary
District
30 City of Mill Valley 16,000 1.5 Secondary Richardson Bay to
San Francisco Bay
31 Richardson Bay 3,300 0.2 Secondary Richardson Bay to
Sanitary District San Francisco Bay
32 Sanitary District No. 5 4,000 Primary Raccoon Strait to
of Mann County - San Francisco Bay
Paradise Cove Plant
33 USD1, Bureau of Mines Primary San Francisco Bay
34 Sanitary District No. 1 1,500 Primary Richardson Bay to
of Mann County - San Francisco Bay
Tiburori Plant
35 San Quentin Prison 6,000 Secondary Corte Nadera Creek to
San Francisco Bay
36 Sanitary District No. 1 50,000 Secondary San Francisco Bay
of Mann County
37 San Rafael Sanitation 25,000 2.6 Secondary San Pablo Bay U’
District - Main Plant
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Table 3. Municipal Waste Sources (cont’d)
Map Population Flow Receiving
Source Served MGD Treatment Water
38 San Rafael Sanitation 1,500 0.1 Secondary San Pablo Bay
District -
Mann Bay Plant
39 Los Gallinos Valley 27,000 1.6 Secondary San Pablo Bay
Sanitary District
40 Hamilton Air Force Base Primary San Pablo Bay
41 Sanitary District No. 6 11,000 0.7 Secondary Novato Creek to
of Mariii County - San Pablo Bay
Ignacio Plant
42 Sanitary District No. 6 24,000 2.3 Secondary Novato Creek to
of Mann County - San Pablo Bay
Novato Plant
43 Sanitary District No. 6 Secondary Petaluma River to
of Mann County - San Pablo Bay
Bahia PLant
SONOK& COUNTY
44 City of Petaluma 24,000 1.8 Secondary Petaluma River to
San Pablo Bay
45 Sonoma Valley County 26,000 1.5 Secondary San Pablo Bay
Sanitation District
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Table 3. Municipal Waste Sources (cont’d)
Map Population Flow Receiving
Source Served MGD Treatment Water
46 Skaggs ]:sland Primary San Pablo Bay
Naval Reservation
NAPA COUNTY
47 Napa County 50,000 5.2 Secondary Napa River to
Sanitation District San Pablo Bay
SOLANO COUNTY
48 Mare Island Naval Secondary San Pablo Bay
Shipyard
49 ValLejo Sanitation & 82,000 7.0 Primary Carquinez Straits
Flood Control District
50 City of Benicia 7,000 0.6 Primary Carquinez Straits
51 Fairfield - Suisun 35,000 3.2 Secondary Suisun Slough to
Sewer District Suisun Bay
52 Travis Air Force Base Secondary Suisun Bay
I . . )
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Table 3. Municipal Waste Sources (cont’d)
Map
Source
Population
Served
Receiving
Water
MGD
Treatment
CONTRA
COSTA
COUNTY
53
City of Pittsburg -
Montezuma St. Plant
16,000
1.2
Primary
New York Slough to
Suisun Bay
54
City of Pittsburg -
Camp Stoneman Plant
8,000
0.5
Primary
New York Slough to
Suisun Bay
55
Contra Costa County
SpeciaL District No. 7A
12,000
0.6
Secondary
Suisun Bay
56
City of Concord
73,000
3.8
Secondary
Walnut Creek to
Suisun Bay
57
Central Contra Costa
County Sanitary
District
275,000
16.3
Primary
Suisun Bay
58
Mountain View Sanitary
District
12,000
0.6
Secondary
Suisun Bay
59
City of Martinez
10,000
1.4
Intermediate
Carquinez Straits
60
Crockett-Velona
Sanitary District
5,000
0.3
Primary
Carquinez Straits
6L
Rodeo Sanitary District
8,000
0.6
Secondary
San Pablo Bay
6
City of Pinole
13,000
0.8
Primary
San Pablo
I . . )
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Table 3. Municipal Waste Sources (cont’d)
Nap Population Flow Receiving
Key Source Served MGD Treatment Water
63 Contra Costa County 12,000 0.7 Secondary San Pablo Bay
Special District No. 3
64 San Pablo Sanitary 69,000 6.2 Primary San Pablo Bay
District
65 City of Richmond 72,000 8.0 Secondary Central San Francisco Bay
66 Stege Sanitary District 45,000 3.9 Primary Central San Francisco Bay
“0
-------
t ’.ApA
Q44
Q45
43t
?/Ait 042
410
4oE
390
380
SAN P F. EL 0 37
360
35
30 31
034
\ 4 29
• ‘-270.
/‘
FR A C C
26
t • S
SC)Tr
240
230
048 49
- \0. LSEJO
06O
061
/
— - - — -- -
050 •. -- - C?: GO 055,,
$58
057
4)62
063 056
4)64
R CHMC ID
j66 4) Primary Treatment
• .0 Secondary Treatment
ErR 1
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30
STORET data are comparable to the 1965 flow data presented in the San Fran-
cisco Bay-Delta Water Quality Control Program)] A summary of the munici-
pal and industrial waste discharges in 1965 by water quality zones is shown
in Table 4. A more detailed summary of the STORET municipal and indus-
trial inventory data is shown in Table 5.
Of the 4,096,000 population served by the municipal treatment facilities
discharging to the Bay system, 1,865,000, or 45 percent, are served by plants
providing primary treatment only. Primary treatment only is provided at 25
of the 66 sources. These primary plants treat about one-half of the total
waste volume.
The STORET inventory data were incomplete with respect to type of treat-
ment units utilized at each sairce. Treatment data were available on enough
sources, however, to indicate that substantial quantities of domestic wastes
may be discharged to the Bay system without chlorination or adequate disinfec-
tion.
Overloading of municipal waste facilities by heavy industrial organic
waste loads during the food processing season has occurred in the past at
such locations as San Jose and Sunnyvale, and may be continuing as a problem
in several areas.
Industrial Waste Sources
Available information on industrial waste discharges in the Bay area is
very meager. The STORET industrial inventory listed only 11 sources of in-
dustrial waste discharges to the Bay system. These sources are listed in
Table 6. These waste discharges total about 37 million gallons per day.
The current validity of these data is unknown.
The SanFrancisco Bay—Delta Water .iality Control Program evaluated
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31
Table 4. Summary of Municipal and Industrial Waste Sources - 1965
Flow B0 Load
Water Quality Zone Waste Source ( MCD) ( 10 ib/yr )
1, 2 & 3 Municipal 273 384
Discrete Industrial 4 -
4 Municipal 78 90
Discrete Industrial 1 -
5, 6 & 7 Municipal 55 52
Discrete Industrial 18 65
Total Municipal and Industrial 429 591
Source: San Francisco Bay - Delta Water Quality Control Program
Table 5. Summary of STORET Inventory of
Municipal and Industrial Waste Sources
Water Municipal Waste Sources Industrial Total
Quality Population Flow Wastes Flow
Zone Served ( MCD) ( MGD) ( MGD )
1 1,134,000 108 0 )
2 308,000 30 13 ) 298
3 1,238,000 135 12 )
4 541,000 72 0 72
5 422,000 36 0 )
6 22,000 2 6 ) 70
7 431,000 26 0 )
Total 4,096,000 409 31 440
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32
Table 6. Industrial Waste Sources
Flow Receiving
Source MGD - Water
ALAMEDA COUNTY
Colgate Palmolive 2.2 South San Francisco Bay
FMC Corporation 1.8 Newark Slough
to South San Francisco Bay
Charles Pfizer Co. 0.2 Temescal Creek
to South San Francisco Bay
SANTA CLARA COUNTY
None
SAN MATE 0 COUNTY
Ideal Cement Co. 11.0 Redwood Creek
to South San Francisco Bay
Merck Co. 10.0 South San Francisco Bay
SAN FRANCISCO COUNTY
None
NARIN COUNTY
None
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33
Table 6. Industrial Waste Sources (cont’d)
Flow Receiving
Source MGD Water
SONOMA COUNTY
None
NAPA COUNTY
None
SOLANO COUNTY
None
CONTRA COSTA COUNTY
Johns-Nanville Products 1.0
Monsanto Chemical Co. 0.1 Suisun Bay
Shell Oil Co. 4.0 Carquinez Straits
American Smelting & 1.0 Carquinez Straits
Refining Co.
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34
industrial waste discharges existing in l965. 2 jThese waste discharges are
summarized by water quality zone in Table 5. Food cannery discharges
to municipal waste systems and industrial waste discharges directly to the
Bay system from petroleum refining, paper processing plants, chemical pro-
cessing plants, steel manufacturing plants and electrical generation plants
were evaluated and summarized. No individual breakdown by waste source is
available.
No information is currently available as to the characteristics of wastes
discharged or to the treatment processes employed. As discussed in the pre-
vious section on water quality problems, it is known that toxic materials
and taste- and odor-producing substances from industrial discharges are
present in the Bay system.
Combined Sewer Overflows
The major cities of San Francisco and Oakland, and several smaller
cities, are partially served by combined sewer systems. Overflows from
these combined sewers can occur during heavy runoff following periods of
precipitation. Such overflows can contribute substantial bacterial contamina-
tion and minor organic pollution. Sewer overflows are most likely to occur
during the winter rainy season, which coincides with the shellfish harvesting
season.
Vessel Pollution
A large volume of commercial shipping passes through the ports of the Bay
area. Numerous vessels ranging from small pleasure craft to large ocean-going
ships ply the waters of the Bay system. Untreated waste discharges from
these vessels, although contributing a small volume relative to overall uaste
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35
discharges in the Bay system, may be significant sources of bacterial con-
tamination, especially in the area of shellfish beds. Spills of oil and
hazardous materials, such as the major oil spill that occurred when two oil
tankers collided in the Golden Gate in early 1971, have created serious
pollution problems and have been the cause of several fish
Dredging
A total of about 8 million cubic yards of material is dredged each
year from the various navigation channels in the Bay system for maintenance
purposes. Much of this dredged material is dumped in spoil areas in other
Bay locations. Additional dredging is done to provide for construction of
shore facilities and other water-related activities. Large volumes of shell
materials are dredged from the South Bay for use in producing cement. These
dredging activities stir up pollutants from the bottom, which are redistri-
buted by wind and tide currents. Disposal of spoil materials also creates
a pollution potential in the vicinity of the spoil areas. The extent of
water quality degradation resulting from dredging activities has not been
evaluated.
Urban Runoff
Much of the area immediately adjacent to the Bay waters is heavily built
up, with much paving and roof surfaces. As a result, even small amounts of
rainfall may produce surface runoff which may carry pollutants into the Bay
system. The magnitude of pollution from this source is unknown. As in the
case of combined sewer overflows, this runoff is most likely to occur during
the period when it is most damaging to the shellfish industry.
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36
Agricultural Drainage
Irrigation return flows and other agricultural runoff from millions of
acres of irrigated land in the Central Valley are carried by the San Juaquin
and Sacramento Rivers through the Delta into the Bay system. This agricul-
tural pollution includes pesticides, nutri’ents, sediments and other dele-
terious materials. Much of this material is distributed throughout the Bay
system by wind and tidal currents. An extensive ederal-State study of the
water quality impact of future agricultural waste waters from the Central
Valley has been made. This study concluded that treatment of agricultural
waste waters for removal of nutrients would be necessary to prevent severe
degradation of waters in the San Francisco Bay system. Pilot studies to
develop such treatment methods are currently underway.
Natural Runoff
Placer mining during the early gold-mining period in California released
very large volumes of fine sediments into the streams of the Sierra Mountains.
Over the past century, these sediment loads have been moved downstream by the
major rivers, with much of the sediment volume ending up in the San Francisco
estuarine system. Although the volume of sediments discharged to the estuary
has decreased in recent years, such sediments,contained in natural runoff,
are still a significant source of pollution of Bay waters. Some sediments
are also discharged to the Bay system by natural runoff from non-urban areas.
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37
IMPACT OF POLLUTION ON THE SHELLFISHING INDUSTRY
A century ago, a major commercial shellfishing industry was centered
on San Francisco Bay. Harvests of oysters and clams reached a peak in the
1890’s and then declined sharply after 1900. Presently, this industry is
essentially non-existent. A number of factors contributed to this decline,
of which water pollution was the most important.
At its peak, the shellfish industry contributed several million dollars
annually to the regional economy. The economic impact of the elimination
of the shellfish fishery has thus been great.
San Francisco Bay is proven ground for commercial culture of oysters.
The only factors preventing reestablishment of commercial oyster-growing
areas are unsuitable water quality and sanitary conditions. In areas where
water quality has improved over past conditions, shellfish have reestablished
themselves. With improved water quality, South San Francisco Bay would
potentially be the best oyster-growing area in California.
There is presently no interstate shipment of oysters or clams out of
California. The State consumes more shellfish than the available supply
and shellfish are shipped in fran other areas. In the past when oyster cul-
ture was practiced in San Francisco Bay, a major interstate industry existed
to supply seed oysters to the oyster farms. San Francisco Bay, with improved
water quality, has the potential to produce a major oyster harvest which
could supply California demands and create a surplus for interstate shipment
to other areas. Such a major oyster industry would create related interstate
shipments of seed oysters as in the past. Pollution of San Francisco Bay has
thus effectively resulted in constraints on interstate shipments of shellfish
and shellfish products.
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38
Oyster Fishery
History - - Historically, the native western oyster ( Ostrea lurida ) was
present in San Francisco Bay in prodigious quantities and clams and mussels
were plentiful. Extensive beds of the oysters were located in shallow areas
along the west side of the Bay. The extent of the shell deposits built up
by the native oysters is reflected by the fact that more than 50 million cu-
bic yards of shell have been dredged from the Bay over the past 30 years and
an estimated 75 million cubic yards still remain in the Bay.
The native oyster was exploited commercially by simply harvesting oysters
from the natural beds. No attempt at oyster culture was made. The intro-
duction of other commercially important oyster species combined with destruc-
tion of oyster beds by siltation and pollution rapidly decreased the impor-
tance of the native oyster. Since 1945, there has been little or no commer-
cial harvest of the native oyster in California.
In 1869, the large eastern oyster ( Crassostrea virgir4ç ) was introduced
to San Francisco Bay. The oyster thrived under culture and provided a major
source of oysters during the next 30 years. The method of culture was simple.
Seed oysters (spat) were imported from East coast locations. The spat attached
to shell pieces were set out in suitable beds and allowed to reach market size.
The adult oysters were then harvested by hand means.
The first commercial beds were located at Sausalito, Point San Quentin,
Sheep Island, Oakland Creek and Alameda Creek.Y These beds were soon aban-
doned, and by 1875 all beds were loLated in South San f rancisco Bay. The
locations of commercial oyster beds in 1890 are shown in Figure 4. The
Oakland and Alameda Creek beds were abandoned because of sewage and traffic
on the Bay.Y The Alvarado beds were abandoned because of adverse hydrn ra nic
conditions.
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0
a tT cr *i
CItART OF
& x Fn Ncisco ;r SAN PAnLO TRAYS
SIOWLXCTILEI.OIXUCJNOF
nysc R CR0 UNDS
A cO ( OF O.(R91
—
Figure 4.
Location of Oyster Beds in 1890
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39
Between 1880 and 1900, the culture of eastern oysters in San Francisco
Bay and the importing of seed oysters from the east coast was a million dol-
lar business. During the 1890’s, the oyster industry was the single most
valuable fishery in California. Records of oyster harvests during this peak
period are incomplete and conflicting, but they do provide an idea of the
major oyster production then existing. Between 1888 and 1895, oyster pro-
duction (whole oysters including shells) was estimated to range from 9 to
15 million pounds annually with a value of 500 to 100 thousand dollars an-
nually.Y Other records of oyster harvests (meats only) indicated that the
peak production of 3,060,000 pounds of oyster meat valued at $867,000 was
reached in 1899. During the 1887 to 1895 period, imports of seed oysters
ranged from 1.0 to 3.3 million pounds annually. Most of the oyster harvest
was obtained from commercial beds totalling 3,000 to 4,000 acres in area. J
About 1900, some unknown factors caused a radical change in the southern
end of San Francisco Bay which adversely affected the growth rate and market
condition of oyscers grown there. Pollution also affected conditions in much
of the Bay. The choicest oyster growing locations were heavily contaminated,
resulting in oysters of poor quality. As a result, the oyster industry was
short-lived. By 1908, oyster production had decreased 95 percent from re-
ported landings in 1892.±J
Attempts were made to grow eastern oysters in other California waters
but met with little success. Shellfish harvests in California continued
a long decline until 1931, when the Pacific oyster ( Crassostrea gig ) was
imported from Japan. Commercial beds were successfully established in
Bodega Lagoon, Tamales Bay and Drakes Estero, small bays on the coast a
short distance north of San Francisco Bay. Culture of the Pacific oyster
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40
was also successful in Humboldt and Morro Bays farther north. Pacific
oysters were not cultured in San Francisco Bay, due to the adverse water
quality conditions still present.
The culture of Pacific oysters revived the California oyster industry
and statewide landings steadily increased except during and immediately after
World War II, when imports of seed oysters from Japan were stopped. At the
same time, the San Francisco Bay oyster fishery steadily declined and pre-
sently is non-existent.
Present Status -- Native oysters are present in significant numbers in
much of the deeper waters of the Central and South San Francisco Bay.!!
There multiplication is limited by the lack of dead shells to which the spat
may attach. The commercial value of these native oysters is unknown.
Eastern and Pacific oysters have not established themselves in the Bay ex-
cept where cultured.
There are presently no commercial oyster beds in the Bay system. A
State allotment of 3,000 acres for oyster cultural purposes in San Pablo Bay
existed in 1962 but was not being utilized.Y Another oyster company had also
expressed interest in the same area. San Pablo Bay appeared to be the least
affected by pollution in 1962 of the several bays in the Bay system. Most of
the bay is physically suitable for oyster culture. Portions of the bay are
closed to sheilfishing because of bacterial contamination and industrial pol-
lution is serious in some areas.
North San Francisco Bay appears to have only a few areas suitable for
oyster culture. No oysters are currently grown there.
South San Francisco Bay is proven ground for oyster culture. No oysters
are presently grown triere commercially due to bacteriaL contamination and
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41
associated public health hazards. The entire South Bay is potentially
valuable oyster ground, perhaps the finest in the StateA-” The only serious
factors limiting its use are pollution and public health restrictions.
In 1966, there were nine shellfish growing areas with a total area of
8,500 acres registered in California.!” Three of these areas totalling
4,400 acres were currently growing shellfish and were approved or condition-
ally approved for shellfish harvesting. One area of 2500 acres was closed
to harvesting. Five areas totalling 1600 acres were listed as biologically
capable of producing shellfish but not currently growing shellfish. The 1 -
cation of each of these areas was not specified. It is not known if any areas
are registered in San Francisco Bay. All areas were designated as intrastate
areas, indicating harvested shellfish are not shipped interstate.
Potential Development -- In view of the physical conditions of the Bay
and the fact that high oyster production capability has been demonstrated in
the past, it is possible that an oyster fishery of exceptional proportions
could be developed.W The major constraint on such development appears to be
water quality. The market for oysters is unfailing and prices excellent. En
past years, the California oyster supply fell far short of the demand and
oysters were shipped in from the North. Interest in reestablishing commercial
beds has been shown by oyster growers. The economic basis for an expanded
oyster industry would appear to exist.
Based on physical conditions, about 175,000 acres of the Bay system are
potential oyster grounds.W In the past, about 3,000 to 4,000 acres of oyster
beds were commercially maintained. In view of the large potential area, it
would appear that as much as 10,000 acres could easily be commercially operated.
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42
During the 1890’s, oyster production was in the range of 2,500 to
5,000 pounds of oysters per acre per year. J This corresponds to an oyster
meat production of 400 to 750 pounds per acre. From 1958 to 1967, oyster
meat production in California averaged about one million pounds annually.
If it is assumed this harvest was taken from the 4400 acres of registered
shellfish areas, the average oyster meat production was about 230 pounds per
acre. This compares favorably with a California Department of Fish and Game
estimate of yields of 150 to 300 pounds per acre for culture of Pacific oysters.Y
The oysters harvested in the 1890’s were eastern oysters, while recent harvests
in California were primarily Pacific oysters.
A yield of 250 pounds per acre of oyster meat from 10,000 acres would
produce an annual harvest of 2.5 million pounds. It can thus be seen that the
oyster fishery potential of San Francisco Bay far exceeds the existing Cali-
fornia oyster fishery.
Clam Fishery
History -- The original shellfish fauna of the Bay system was extensive,
but few species were of commercial importance. The most common edible species
was the bent-nose clam ( Macoma nasuta) . Large quantities of these clams were
probably dug from the South Bay for the market prior to l 87 Ô.
The soft-shelled clam was accidentally introduced in oyster shipments
about 1870. It soon displaced the native species and became widely distri-
buted. It is an excellent food clam and formed the bulk of the San Francisco
clam trade. The mud flats of San Pablo Bay and the South Bay were particular-
ly favorable locations.
Harvests of clams from the Bay system exhibited the same rise and fall
as the oyster fishery. Between 1880 and 1900, the clam production ranged
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43
between one and three million pounds annually, the highest production re-
corded. L’ After 1900, clam production decreased sharply. Pollution and
excessive digging contributed to this decline. Between 1916 and 1935, the
annual harvest ranged from 100 to 300 thousand pounds. The production con-
tinued to decline after 1935 and was essentially zero after l949. J
Present Status -- No commercial harvesting of clams from the Bay system
is currently done, although some sport clamming takes place. Clams are abun-
dant in several areas, but bacterial contamination makes sport or commercial
harves ting unsafe.
San Pablo Bay formerly produced the greatest share of clams in the Bay
system. This source has not been exploited recently, largely because of the
public health problem. Soft-shell clams were still present in good numbers
in
Clams are also currently present in areas of the South San Francisco Bay.!1’
However, domestic and industrial pollution have resulted in the complete loss
of the South Bay clam fishery. 1’ In areas where water quality improvement has
allowed clams to reestablish themselves, contamination of these clams poses a
health hazard preventing their safe harvest.
In North San Francisco Bay, clam habitat is limited. Only a few clams
are currently present.
Potential Development -- The potential for development of the clam fishery
differs significantly from chat of the oyster fishery. Labor costs are high
for the digging of clams. To maintain a commercially harvestable clam popula-
tion, substantial habitat improvement including fencing against aquatic preda-
tors must be done. Thus, if water quality constraints were lifted, economic
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44
constraints might limit any substantial development of the clam fishery.
No estimates of potential clam production or of the size or value of the
standing clam crop are available.
Economic Impacts
Both the oyster and clam fishery in the San Francisco Bay system have
been either greatly reduced or completely eliminated by the effects of pol-
lution for many years. The major fishery existing prior to 1900 was essen-
tially eliminated as a factor in the regional economy. Since 1930, a major
increase in the oyster fishery at other California locations indicates that
the San Francisco fishery could have thrived economically if water quality
constraints were removed.
It is impossible to estimate the economic impact that has accrued during
the past 70 years as a result of this lost fishery. It is obvious, however,
that the elimination of an industry generating a million dollars annually in
1900 was a major economic impact.
There are two possible approaches to evaluating the approximate magni-
tude of the economic impact of the pollution-eliminated shellfish fishery.
Since the growth of the shellfish industry in other areas of California was
primarily the result of a shift in commercial beds from San Francisco Bay
to these areas as Bay beds became polluted, the value of the out-state fishery
could be considered one measure of the value of the lost fishery. A second
estimate can be obtained from the value of the potential production discussed
previously.
Fishery statistics are available by fishing region for the period from
1939 to 1967.21 The San Francisco fishing region includes the Bay system and
coastal waters from Point Arena to Pigeon Poinc including Tomales Bay, Bodeg
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45
Bay, Bolinas Lagoon and Drakes Estero. The weight and value of the oyster
harvest in the San Francisco region is shown in Table 7. Concurrent fig-
ures for California are shown in Table 8. By subtracting the regional
figures from the State figures, the value of the out-state oyster harvest
can be evaluated. For the period 1958-1967, this harvest was valued at
$2,050,000, an annual value of $205,000.
As shown in Table 7, the dockside value of oysters in the San Fran-
cisco region has fluctuated substantially, largely as a function of supply.
Over the last five years for which published statistics are available, the
price steadily increased, however, while the supply remained relatively con-
stant. The most recent price available (1967) was $0.40 per pound of oyster meat.
As discussed above, it is believed that San Francisco Bay could poten-
tially maintain an annual production of oyster meats of 2.5 million pounds
if water quality constraints were removed. At 1967 prices, this production
would have a dockside value of $1 million per year.
There has been no recent sale of significant amounts of clams in the
San Francisco area. No estimates of potential production are available.
Therefore, no estimate can be made of the economic impact of the loss of the
clam fishery.
Various studies have shown that the economic impact of the shellfish in-
dustry on the regional economy is about four times the dockside value of shell-
fish products)&” Using this multiplier, the total economic impact of pollu-
tion on the economy of the San Francisco area as the result of the loss ot
the oyster fishery is in the range of $820,000 to $4,000,000. This esti-
mate considers only the multiplied economic effect of the harvested oysters.
An additional economic impact would be produced by the importation of seed
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46
Table 7. Summary of Oyster Harvest
San Francisco Fishing Region
Total Oyster Harvest Value Price
Year ( 1,000 pounds of meat) ( $1,000) ( $/# )
1939 242 50 0.21
1940 180 25 0.14
1941 240 42 0.18
1942 50 17 0.34
1943 57 19 0.33
1944 35 24 0.69
1945 19 17 0.90
1946 12 14 1.17
1947 19 22 1.16
1948 48 53 1.10
1949 20 18 0.90
1950 32 35 1.09
1951 41 53 1.29
1952 39 46 1.18
1953 34 43 1.26
1954 36 47 1.30
1955 42 56 1.33
1956 59 75 1.27
1957 64 41 0.64
1958 75 54 0.72
1959 54 42 0.78
1960 32 34 1.06
1961 79 63 0.80
1962 61 46 0.75
1963 186 36 0.19
1964 213 47 0.22
1965 195 64 0.33
1966 234 92 0.39
1967 199 81 0.40
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47
Table 8. Summary of California Oyster Harvest
Total Oyster Harvest Value Unit Price
Year ( 1,000 pounds of meat) ( $1,000) ( $/# )
1892 1,316
1895 1,145 — -
1899 3,060 867 .28
1904 1,406 536 .38
1908 729 337 .46
1915 387 166 .43
1922 74 - -
1923 69 24 .35
1924 53 23 .43
1925 57 24 .43
1926 61 26 .43
1927 55 24 .43
1928 77 32 .43
1929 53 27 .50
1930 78 32 .42
1931 245 76 .32
1932 59 19 .33
1933 86 29 .33
1934 101 43 .43
1935 107 40 .37
1936 105 27 .26
1937 163 38 .24
1938 213 50 .23
1939 246 51 .21
1940 193 27 . 14
1941 256 48 .19
1942 85 29 .34
1943 117 38 .33
1944 90 48 .53
1945 48 28 .59
1946 22 19 .86
1947 24 26 1.05
1948 66 63 .95
1949 35 26 .76
1950 39 36 .94
1951 43 46 1.06
1952 45 47 1.04
1953 38 44 1.18
1954 74 54 .73
1955 218 89 .40
1956 756 178 .23
1957 1,359 287 .21
1958 1,159 242 .21
1959 1,653 309 .19
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Table 8. Summary of California Oyster Harvest (cont’d)
Total Oyster Harvest Value Unit Price
Year ( 1,000 pounds of meat) ( $l,000) ( $f# )
1960 1,283 289 .23
1961 1,221 296 .25
1962 1,339 306 .23
1963 1,300 226 .17
1964 1,360 254 .19
1965 1,063 263 .25
1966 790 222 .28
1967 742 207 .28
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oysters to supply cultural requirements. This economic effect is unknown.
An additional but unknown economic impact also is produced by the loss of
the clam and mussel fishery.
Interstate Aspects
There are currently no interstate shipments of oysters out of California.
No interstate shippers are registered.!! The state consumes a greater amount
of shellfish than can be supplied locally and oysters are shipped in from
the North. In the sense that the loss of the San Francisco Bay oyster fish-
ery to pollution creates a greater need for interstate imports of shellfish,
pollution of San Francisco Bay directly affects interstate shipments of shell-
fish.
San Francisco Bay has the potential to produce a shellfish supply ade-
quate to meet local needs and create a surplus which could be marketed in
interstate commerce. Pollution of the Bay prevents the realization of this
potential.
Large-scale commercial production of oysters in San Francisco Bay would
require culture of either Eastern oysters or Pacific oysters. The Eastern
variety was successfully cultured in the past and Pacific oysters are cul-
tured in other California bays. Such cultural practices would require the
interstate importation of large numbers of seed oysters. Pollution of San
Francisco Bay prevents the practice of oyster culture and thus prevents the
market of seed oysters in interstate commerce to provide the basis for oyster
production.
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50
REFERENCES
1. California State Water Resources Control Board, “San Francisco Bay-
Delta Water Quality Control Program”, Sacramento, California,
March, 1969.
2. DeLisle, Glenn, California Department of Fish and Came, “Preliminary
Fish and Wildlife Plan for San Francisco Bay-Estuary”, Prepared for
San Francisco Bay Conservation and Development Commission,
October 1966.
3. San Francisco Bay Conservation and Development Commission, State of
California, “San Francisco Bay Plan”, San Francisco, California,
January, 1969.
4. Skinner, John E., “An Historical Review of the Fish and Wildlife Re-
sources of the San Francisco Bay Area”, Water Projects Branch Report
No. 1, The Resources Agency of California, Department of Fish and
Game, Water Projects Branch, June 1962.
5. American Public Health Association, Subcommittee on Water Quality
Control, “Water Quality Standards of the United States, Territories
and the District of Columbia”, June 1969.
6. Federal Water Pollution Control Administration, U. S. Department of
the Interior, “Report of the National Technical Advisory Committee
to the Secretary of the Interior”, Washington, D. C., April 1, 1968.
7. Bureau of Commercial Fisheries, U. S. Fish and Wildlife Service,
Department of the Interior, “Fishery Statistics of the United States,
1939 to 1967”.
8. Public Health Service, U. S. Department of Health, Education, and
Welfare, “National Register of Shellfish Production Areas”, Washing-
ton, D. C., 1966.
9. Public Health Service, Food and Drug Administration, U. S. Department
of Health, Education, and Welfare, “Interstate Shellfish Shippers
List”, February 1971.
10. Colbert, J. R., and D. N. Windham, “The Oyster Based Economy of Franklin
County, Florida”, Public Health Service, U. S. Department of Health,
Education, and Welfare.
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