In situ Ecosystem Effects of Trace Contaminants in the San Francisco Bay Estuary: The Necessary Link to Establishing Water Quality Standards

By Janet K. Thompson, Francis Parchaso, Cynthia L. Brown, and Samuel N. Luoma

Open-File Report 96-437

Menlo Park, California 1996

U. S. DEPARTMENT OF INTERIORBRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEYGorden P. Eaton, Director

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

For additional information write to:

Janet K. Thompson Water Resources Division U.S. Geological Survey 345 Middlefield Rd., MS496 Menlo Park, California 94025 jthompso@usgs.gov

Copies of this report can be purchased from

U.S. Geological Survey Earth Science Information Center Open-File Reports Section Box 25286, MS517 Denver Federal Center Denver, Colorado 80225

Table of Contents

Abstract ......................................................... 1

Acknowledgments .................................................. 2

Introduction ....................................................... 3

Background on Potamocorbula amurensis ................................... 4

Environmental Setting ................................................ 5

Summary of Contaminant and Condition Data ................................ 6

Methods ..................................................... 6

Collection Methods .......................................... 6Reproductive Tissue Preparation .................................... 7Categories of Gonadal Development (Adapted from Rosenblum 1981) .......... 7

Female Gonads: .......................................... 7Male gonads: ............................................ 8

Environmental Data ............................................ 8

Results .......................................................... 9

San Pablo Bay - Station 12.5 ...................................... 9Carquinez Strait- Station 8.1 ...................................... 9Suisun Bay - Station 6.1 ......................................... 9Chips Island- Station 4.1 ........................................ 10Honker Bay - Station 433 ........................................ 10

Discussion ....................................................... 10

Reproductive Cycle and Environmental Factors .......................... 10San Pablo Bay - Station 12.5 : ................................ 11Carquinez Strait- Station 8.1: ................................. 11Suisun Bay - Station 6.1: ................................... 12Chipps Island- Station 4.1: .................................. 12Honker Bay - Station 433: ................................... 12Summary: .............................................. 13

Condition and Reproduction ..................................... 13San Pablo Bay - Station 12.5: ................................ 14Carquinez Strait- Station 8.1 ................................. 14Suisun Bay - Station 6.1: ................................... 14Chipps Island- Station 4.1: .................................. 14Honker Bay - Station 433: ................................... 14Summary: .............................................. 15

Reproductive Cycle and Cadmium Concentration ......................... 15

Conclusions ...................................................... 16

References ....................................................... 17

Tables 1 and 2.

Figures 1 through 47.

Appendix I.

Conversion Table

Multiply By To Obtain

Multiply By To Obtainmeter (m) 3.28 footmicron (nm) 3.94x10-5 inchmilligram (mg) 2.20x10-6 poundgram (g) 2.20 xlO-3 poundliter (L) 1.06 quartcubic meter/sec 35.3147 cubic feet/sec

Temperature is given in degrees Celsius (°C) and can be converted to degrees Fahrenheit (°F) using the following equation:

°F= 1.8(°C)+32

AbstractReproduction and condition of Potamocorbula amurensis were compared with cadmium

concentration in the tissues of individual P. amurensis from five stations in northern San Francisco Bay to determine if either parameter could be used to assess ecosystem effects of trace metal

contaminants. There is a gradient in cadmium content (ug/animal) and concentration (ng/g dry

tissue) in tissues of clams which follows the freshwater gradient, with the freshest stations having the highest levels of cadmium contamination. Condition decreases with increasing cadmium content; animals from Honker Bay and Chipps Island have the highest cadmium content and lowest condition and those from San Pablo Bay have the lowest cadmium levels and highest condition. Synchrony in spawning was similarly related to cadmium content; animals with the highest

cadmium concentration have asynchronous spawning. Asynchrony is potentially deleterious to

organisms which depend on external fertilization, and thus may indicate that the reproductive

success of other organisms in Suisun and San Pablo Bays may be harmed. The number of reproductive cycles, timing of reproduction, speed with which animals regain weight after spawning, and amount of weight gained during spawning, are most strongly related to food availability.

AcknowledgmentsWe are grateful to Regina Linville, Oscar Mace, Scott Shapley, Jody Edmunds, and

Christina Tyler for their help in collecting animals, and to J. Edmunds and F. H. Nichols for their

critical review of the manuscript.

IntroductionThe ecosystem effects of trace contaminants are the subject of ongoing discussions within

San Francisco Bay regulatory agencies. Water-quality standards for all trace contaminants will be established within the next few years, and will be based on the ecological effects of each of the metals. Water-quality standards are established after preliminary standards are published,

reviewed by the public, modified, and then subjected to further review. These regulatory

processes will take several years to complete and the decisions will be aided by data describing the ecological effects of these contaminants. Trace-metal concentrations in San Francisco Bay are presently being assessed by analyzing the water column and the sediment, by doing bioassay tests

on specific organisms, and by studying tissue burdens in some species. Although the ultimate goal

of these studies is to determine what level of contamination results in harmful effects to the ecosystem, none of these approaches directly measures the effect of contaminants on the ecosystem. The major reason that direct measures of ecosystem effects have not been made is that

the complexity of ecological processes can hide correlations between organism, population, or

community changes and trace element concentrations.Some of this complexity is reflected in the way in which contaminants can affect animals

and the communities in which they live. Chemical-biological interactions at the molecular level

within an organism can influence developmental stages resulting in reproductive abnormalities,

toxicity and adaptation due to changes in metabolic processes, and cellular damage due to effects on mitotic processes. At the organism level, contaminant stress can be seen with changes in physiology, behavior, reproductive success, larval success, and rates of parasitism and disease.

At the more complex population level, changes in mortality, recruitment, biomass, production, and the structure of age and size classes are all possible effects of contaminants. At the community level, contaminant exposure may result in changes in species diversity, species composition,

secondary production, and biomass. However, environmental stress, eg. osmotic and thermal

extremes, can also cause many of the same effects. Thus, if ecosystem effects of contaminants are

to be measured, it is necessary to examine selected parameters in a manner in which environmental

and contaminant stresses can be separated.This report is the first step in looking at ecosystem effects of trace elements. Two life

history parameters, reproductive periodicity and condition (change in tissue weight for a specific

size of animal) of one species, Potamocorbula amurensis, are examined within a reach of San Francisco Bay that has a known trace metal concentration gradient (Brown and Luoma 1995). The

contaminants within this gradient appear to originate with the freshwater inflow, i.e. the

contaminant gradient opposes the salinity gradient. The presence of a salinity gradient within the study area supports the importance of addressing the effects of environmental and trace metal stresses separately, and in combination with each other. This approach is possible for the

following reasons: 1) Infaunal communities along the contaminant gradient are dominated (>95%

of biomass) by a single species, P. amurensis, which reduces the complexity of the ecosystem such that species interactions and community "effects"are minimized (Nichols et al., 1990). 2) P. amurensis lives in a broader salinity range than the salinity range of the study area. Thus, although animals may react to salinity variations, lethal osmotic stress is unlikely. 3) The coincident collection of environmental data (e.g. salinity, temperature, chlorophyll a concentration) allows us to analyze "natural" environmental stresses as well as stresses due to the contaminants. 4) The trace metal and ecological data were collected at the same times and locations. 5) The study includes a

large range of environmental stress; the study period encompasses a time when temporal

variability, and therefore environmental stresses, were small due to the drought (1991, 1992, and 1994) and a period of normal freshwater inflow (1993), when larger environmental stresses are expected. 6) Our studies of P. amurensis since its introduction in 1988 have provided a good

database of population and community characteristics throughout the bay.

Background on Potamocorbula amurensisPotamocorbula amurensis (family Corbulidae) is a native of China, Japan, and Korea, and

was introduced, most likely by an inoculation with ballast water, into San Francisco Bay in late

1986 (Carlton et al., 1990). Since its introduction, P. amurensis spread rapidly and became, by 1990, the dominant bivalve (based on biomass) in much of the bay (J. Thompson, unpublished data). P. amurensis is capable of living in all bathymetric and sedimentary habitats in the bay,

including those exposed to large seasonal changes in salinity, temperature, and sediment

composition. These characteristics, in conjunction with the clams' fast growth rate (J. Thompson, unpublished data), early age at reproductive readiness (Parchaso, 1993), and voracious feeding

rates (Cole et al., 1992) suggest that P. amurensis is an opportunistic or r-selected species.

Therefore P. amurensis might be expected to be very tolerant of environmental stress and exhibit various reactions to stress;/.e. stress which negatively affects one part of the life history of the organism, such as reproduction, may not affect other, equally vital functions, such as growth.

Brown and Luoma (1995) concluded that "Potamocorbula amurensis is an effective biosentinel for studying processes controlling trace contamination and bioavailability in San

Francisco Bay because it is found throughout the bay, has an unusually wide salinity tolerance and is sensitive in indicating environmental differences in trace metal uptake." (Brown and Luoma,

1995). Thus it is expected that observed changes in some life history parameter of P. amurensis

that correlates with contaminant concentrations in its tissue may also be related to similar

contaminant concentrations in the environment.

The goal of this study is to begin assessing the response of an in situ population to a contaminant and to the concomitant environmental stresses. This report contains a description of the environmental conditions observed during the study and an overview of the condition data and the concentration and content data for one contaminant, cadmium. This metal is used as a

surrogate for other freshwater derived contaminants. Neither the contaminant or condition data

will be described in detail here as these can be found in Brown and Luoma, 1995. The reproductive cycle of animals along this contaminant gradient will be described in detail at each station and will be examined relative to environmental conditions and condition indices.

Environmental SettingStations were chosen along the salinity gradient in northern San Francisco Bay to be

representative of the benthic communities based on a survey of 200 stations in 1988 (Thompson

unpublished data). The four channel stations (fig. 1, table 1), stations 4.1, 6.1, 8.1, and 12.5, are near U.S. Geological Survey (USGS) hydrologic monitoring stations 4, 6, 8, and 12 (Conomos et al., 1985); the three upstream stations are also near the California Department of Water

Resources (DWR) monitoring stations D10, D8, and D6. The Chipps Island station (4.1) is the

most upstream station and has a sandy to muddy sand substrate. The Honker Bay station (433),

the only non-channel station, is located near the Chipps Island station, has a mud or peaty mud substrate, and may receive freshwater from up-river of station 4.1 through Spoonbill Creek (fig. 1). The Suisun Bay station (6.1) has a muddy sand substrate and may have been intermittently disturbed by a sand dredge. Station 8.1 is at the eastern end of the Carquinez Strait, a narrow high

current velocity section of the bay, and has a heterogenous bottom with pockets of hard clay, sand,

and mud. The San Pablo Bay station (12.5) is on the channel edge adjacent to a the broad expanse

of intertidal areas in San Pablo Bay (fig. 1)., and has a muddy substrate. It is most likely that, of

the channel stations, this station would most freely exchange water with the shallow reaches.

The study period, January 1991 through December 1994, included three drought years and one normal run-off year. Following a major flood in 1986, northern California began a six year drought which ended in 1993 (fig. 2). The rainfall and snowpack, both of which result in

freshwater inflow into San Francisco Bay, were again low enough in 1994 for that year to be

considered a drought year. Surface water electrical conductivity and temperature near Mallard Island and Martinez (fig. 1) show how this change in the hydrograph during our study period

affected these parameters in the vicinity of our four upstream stations (figs. 3 and 4).Until 1986 the northern estuary had a late summer to early fall phytoplankton bloom (fig.

5). The cessation of this annual phytoplankton bloom since 1986 coincided with the introduction of Potamocorbula amurensis and it is believed that the lack of a phytoplankton bloom is due to over grazing by this filter feeder (Alpine and Cloern 1992). Therefore the major sources of food for P. amurensis, a filter feeder, are a combination of riverborne detritus and river derived phytoplankton in addition to locally grown phytoplankton, which never reaches high biomass levels. Each of these sources has a different seasonal and interannual pattern (fig. 6). The riverborne detritus is richest in non-refractory carbon at the beginning, not the peak, of the freshwater run-off during each year (Hagerand Schemel 1996) and was, no doubt, quite high in early 1993 when the drought ended. River chlorophyll a peaks in late spring and summer, but its transport into the bay is dependent on the amount and timing of freshwater runoff, so its quantity and seasonality vary between years. Growth rates of locally derived phytoplankton are dependent on light availability (Cloern 1987) and in this part of the estuary the growth rates usually peak in summer and fall.

Summary of Contaminant and Condition DataBoth cadmium content (jig in a 15mm animal, fig. 7) and concentration (|ig/g dry tissue,

fig. 8) show a down-bay gradient with highest values seen in Honker Bay animals and the lowest values seen in San Pablo Bay animals (Brown and Luoma, written commun., 1996). Annual mean cadmium content was highest in 1993 in animals from the three upstream stations, showed little annual variation in Carquinez Strait animals, and was lowest in 1993 in San Pablo Bay animals (fig. 9). Condition for P. amurensis was generally higher at the down bay stations than at the freshest stations (fig. 10). Annual mean condition (fig. 11) was highest in animals from the seaward stations, San Pablo Bay and Carquinez Straits, and lowest in animals from Honker Bay.

Methods Collection Methods

To determine the reproductive pattern and gonadal development of P. amurensis, monthly samples were collected from the four channel stations and one shallow station for a period of 47 months, from January 1991 to December 1994. Animals representative of the size range present at each site were collected on the United States Geological Survey (USGS) research vessel Polaris

with a Van Veen grab (0.05 m2) and rinsed through a 0.5 mm sieve, and preserved in 10 percent buffered formalin.

Fifteen clams were examined for reproductive condition during 1991 for each sampling date and station and 10 clams were examined for each sampling date and station for the remaining years. There were several periods at all stations when no clams were found (table 2) and some periods when the sample size was reduced due to tissue damage during histological preparation.

Reproductive Tissue PreparationClam tissue was prepared and thin-sectioned by Bay Histology (San Rafael, California).

The visceral mass of each clam was removed, stored in 70 percent ethyl alcohol, and then prepared

using standard histological techniques: tissues were dehydrated in a graded series of alcohol, cleared in toluene (twice for one hour each), and infiltrated in a saturated solution of toluene and Paraplast for one hour, and two changes of melted Tissuemat for one hour each. Samples were then embedded in Paraplast in a vacuum chamber. The embedded samples were thin sectioned (10

Hm) using a microtome and then stained with Harris' hematoxylin and eosin. The stained thin

sections were examined with a light microscope. Each specimen was characterized by size (length), sex, developmental stage and condition of the gonads thus allowing each specimen to be placed in one of five qualitative classes of gonadal development.

Categories of Gonadal Development (Adapted from Rosenblum 1981)

Female Gonads:Inactive Phase. Sex may be difficult or impossible to determine. Small ovocytes occur at the

periphery of alveoli. A round nucleus in the ovocyte, encircled by an irregularly shaped

cytoplasm, contains a conspicuous nucleolus. Follicle cells completely imbed the ovocytes and may fill the lumina of alveoli.Active Phase. Definite qualitative and quantitative changes in the gonads occur. Enlarging

ovocytes grow between follicle cells towards the centers of alveoli. The ovocytes may be sub-

conical, hemispherical, or cylindrical in shape, are rounded at the apices, and have broad

cytoplasmic bases attaching them to the walls of the alveolus.

Ripe Phase. Ovocytes appear as round cells in the lumina of the alveoli as if free of attachment to

the basal membrane, but attachment is via a slender stalk. The nuclei of the largest ovocytes

contain amphinucleoli, each consisting of an almost transparent nucleolus and a small opaque nucleolus membrane in cross section. The large ovocytes that fill the lumina are generally more

numerous than the less-developed ovocytes.

Partially Spawned Phase. Gonadal tissues contain a few ripe ovocytes. Small ovocytes are imbedded in follicle cells at the periphery of an empty alveolus. Many alveoli are devoid of ripe

ovocytes.Spent Phase. Very few ripe ovocytes are present. Numerous spherical droplets of lipoids andother products of cytolysis are characteristic. The spent phase progresses into the inactive phase.

Male gonads:Inactive Phase. During the inactive phase, male tissues contain products of atypicalspermatogenesis. Tissues appear active although this activity will not result in viable sperm.

Pycnoitic cells (cells with moribund and shrunken nuclei) and multinucleated cells appear in thefollicles. Follicle cells fill the alveoli, surround the aberrant cells and the few spermatogonia andprimary spermatocytes at the periphery of the alveoli.

Active Phase. Proliferating primary spermatocytes exist at the basal membrane or the alveoli.

These are small and uniformly sized cells which are similar to the earliest ovocytes. They can be

seen growing between follicle cells, extending towards the centers of the alveoli. Early stages ofmeiosis occur at the periphery of the alveoli, while spermatids occur at the alveolar centers wherethey later form a distinct mass. The follicle cells eventually disappear.Ripe Phase. Masses of spermatozoa arranged in more or less radial columns exist in roundedalveoli with tails oriented toward the center.

Partially Spawned Phase. Relatively few spermatozoa can be seen. Follicle cells start to refill

alveoli. Some pycnoitic cells occur.

Spent Phase. Spent male tissues contain no or few spermatozoa in the central alveolar area.

Numerous follicle cells with multinucleated cells and pycnoitic cells from atypical spermatogeneticactivities surround small groups of spermatozoa. Tissues lack cells in the active phase ofspermatogenesis.

Environmental DataFreshwater inflow is estimated using the Delta Outflow Index as calculated by DWR.

Chlorophyll a concentration is based on DWR data at stations D9 (near station 433), D10 (near

station 4.1), D8 (near station 6.1), D6 (near station 8.1) (DWR database 1991-1994) and based on USGS data at station 12 (Caffrey and others, 1994, Edmonds and others, 1995, Wienke and others, 1992, 1993) and DWR data at station D41 for station 12.5 . The temperature and electrical

conductivity data for surface water at Mallard Island and Martmez (figs. 3 and 4, DWR database 1991-1994) were used for comparison with reproduction data at the three upstream stations and at

the Carquinez Strait station respectively. Temperature and salinity data, collected by DWR (station D41, DWR database 1991-1994) was used for comparison to the San Pablo Bay reproduction

data. Irradiance data, shown for the first three years of the study, are a combination of insolation data at Redwood City which are collected by the USGS and air pollution data collected for the city

of San Jose, California.

ResultsReproductive data are displayed as cumulative percentages of ripe, spawning, and spent

animals; the non-tinted parts of the graphs are a combination of active and inactive animals (see

appendix 1 for the complete reproduction data). As this presentation can be difficult to interpret, two of these stages, ripe and spawning, are displayed as cumulative and simple percentages in a hypothetical population with four different spawning cycles (figs. 12a and 12b). As synchrony in spawning within populations is an important factor in this report, this hypothetical population is

shown with increasing asynchrony from the first to the fourth cycle (fig. 12c). The first cycle is

totally synchronous (i.e. all organisms in the population spawn at one time) which results in a

ripe/spawn ratio of zero. The second through fourth cycles have an increasing percentage of the population occurring concurrently in the ripe and spawning stages. We have considered the second cycle, when a few animals spawn early and late relative to the rest of the population, to be synchronous. Animals in the third and fourth cycles are considered to be asynchronous with some percentage of the population concurrently in a ripe and spawned stage over several months.

San Pablo Bay - Station 12.5

San Pablo Bay animals appeared to have two distinct reproductive periods, one in spring and one in fall. Animals were in a nearly continuous state of ripe, spawning or spent from January 1992 through September of 1993 (fig. 13, app. 1). The highest percentages of inactive animals were seen in fall 1993 and 1994. Spawning was synchronous in spring of 1993 and 1994 and strongly asynchronous in the preceding years and in fall of 1994.

Carquinez Strait- Station 8.1

Animals in Carquinez Strait had one reproductive cycle each year. Spawning was distinctly

synchronous in 1992 through 1994, and possibly asynchronous in 1991. There were also longer periods of inactivity at this station (fig. 14, app. 1) than was seen at other stations.

Suisun Bay - Station 6.1

Suisun Bay animals had two reproductive cycles per year in most of the years, with the

second cycle being much smaller than the first cycle during most years. Gametes entered the late

stage of development in late fall or early winter and were released in spring (fig. 15, app. 1). Spawning was asynchronous in 1991 through 1993 and synchronous in 1994 (fig. 15).

Chips Island- Station 4.1

Animals at Chips Island had distinct periods of inactivity in fall of each year followed by a

single reproductive period which began in late fall and continued into spring (fig. 16, app. 1). There is indication of a second reproductive cycle beginning in summer of 1991 but our inability to collect animals in several of the summer and fall months makes it difficult to confirm this. Spawning was not synchronous during any of the years although there were periods when the population was entirely spent and inactive, or spawning and spent (for example 1994).

Honker Bay - Station 433

Animals at the Honker Bay site were reproductively active throughout the year and had the lowest percentage of animals in an inactive stage of all of the stations. This resulted in a large percentage of the population being in a ripe, spawned, or spent stage most of the time (fig. 17, app. 1). This phenomenon was particularly evident in 1993 and 1994 (fig. 17) when no animals were found in an inactive phase or an active phase from January 1993 through February 1994 and August through December 1994 (note that no animals were found in March through July 1994).

This was apparently due to animals cycling from the spent phase through the active and into the

ripe phases within the time between samples (usually 4 weeks). There were two reproductive

periods in Honker Bay animals in each year with gametes being released in late winter/early spring and again in late summer/early fall. Spawning was not synchronous for this population as there were several contiguous months when a sizeable portion of the population was coincidentally in the ripe, spawned, and spent stages.

DiscussionReproductive Cycle and Emnronmental Factors

Environmental conditions are compared wiyh reproductive activity in the following sections. The percentage of animals at the beginning of gametogenesis (active stage) and the percent of those spawning (that is when there is a sharp drop in the number of ripe animals) were

chosen for discussion as both reproductive stages are usually triggered by some environmental cue

in organisms with external fertilization. The use of environmental cues insures that these animals

release their gametes in synchrony, thereby increasing the chance of successful fertilization. The environmental factors considered in our interpretation of the reproduction data are volume of

10

freshwater inflow, electrical conductivity or salinity, water temperature, water column chlorophyll a concentration, and irradiance. Freshwater inflow is examined as it is an important carrier of food from allochthonous carbon sources and is a possible stressor if the animals are affected by changes in salinity and temperature. As noted earlier, the earliest run-off, not the peak run-off, of the rainy season carries the highest percentage of participate organic carbon (Hager and Schemel 1996), and thus it is the first signs of freshwater inflow that may be important as a carrier of the allochthonous carbon. Chlorophyll a concentration is discussed because it is a measure of

phytoplankton biomass. However, chlorophyll a does not distinguish between viable and non- viable phytoplankton cells, and therefore, although an increase in chlorophyll a concentration does indicate an available food source, it does not necessarily indicate a growing phytoplankton population. In this study , there was at least one instance (summer 1993) when the phytoplankton that composed the chlorophyll a concentration peak in Suisun Bay were predominately Melosira

lirata (Caffrey et al. 1994), a freshwater species that was washed out from the San Joaquin River

and unlikely to be viable in the estuary. Due to the overgrazing of the phytoplankton populations

that was discussed earlier, biomass levels (chlorophyll a) cannot be used as a measure of

phytoplankton growth rate. The only measure we have of the food supplied by increased

phytoplankton growth is irradiance (shown by Cloern and others (1985) to generally correspond to growth rate) which is therefore used as a measure of the availability of autochthonous food

sources.

San Pablo Bay - Station 12.5 : The onset of gametogenesis in spring in San Pablo Bay animals

appeared to coincide with the first increase in freshwater inflow (fig. 18a). Animals became ripe in fall coincident with peak irradiance (figs. 20a and 20b). Spawning usually followed peaks in chlorophyll a concentration (figure 19b) or freshwater inflow (figure 18b). Reproductive activity showed no direct relationship to salinity or temperature at this station with animals developing

gametes and spawning throughout the salinity and temperature ranges (figs. 2la, 21b, 22a, and

22b).

Carquinez Strait- Station 8.1: Gametogenesis in Carquinez Strait animals began during initial increases in freshwater inflow except in 1992 (fig. 23a) and animals became ripe during peak freshwater flows (fig. 23b). Spawning occurred with large increases in chlorophyll a concentration in 1992 and 1993 and with small increases in chlorophyll concentration and irradiance in 1991 and 1994 (figs. 24b and 25b). Thus environmental factors which increase

phytoplankton growth rates may have been important as a spawning cue in 1991 and 1994 despite

low phytoplankton biomass levels.Carquinez Strait animals became active during the highest electrical conductivities (EC) of

11

each year (fig. 26a) and spawned with or immediately after the low EC of each year (fig. 26b) although the absolute values of these parameters were not the same during each year. The relationship between reproductive periodicity and temperature was unclear, with gametogenesis beginning with temperatures ranging from 14-22° C (fig. 27a) and animals spawning from 8-15° C(fig. 27b).

Suisun Bay - Station 6.1: Gametogenesis in Suisun Bay animals began with the first freshwater

inflow in all years (figs. 28a). Animals in 1993 began to develop new gametes immediately after

the winter spawn (figs. 15, 28a, 28b) coinciding with a period of extended freshwater inflow. Animals became ripe during the peak freshwater inflow (fig. 28b) or, in the case of the second reproductive period in 1993, coincident with a dramatic increase in chlorophyll a concentration (fig. 29b) and irradiance (figure 30b). Animals in all years spawned within two months of peaks

in freshwater inflow but no distinct cue at the time of spawning was evident in 1991 and 1994. Animals did spawn coincident with, or following increases in chlorophyll a concentration in 1992

and 1993 (fig. 29b).Suisun Bay animals were similar to those elsewhere with no specific range of EC or

temperature being necessary for gamete development or spawning (figs. 3 la and 32a). Chipps Island- Station 4.1: As elsewhere, the reproductive periodicity of animals at Chipps Island corresponds most closely to peaks in freshwater inflow (fig. 33) with some secondary influence

by increases in chlorophyll a concentration (fig. 34). Animals began gametogenesis with the first

increase in freshwater (fig. 33a), and became ripe coincident with, or preceding the peak freshwater runoff (fig. 33b). Spawning occurred either during the maximum freshwater inflow (1991 and 1992, fig. 33b) or with peaks in chlorophyll a concentration (1993 and 1994, fig. 34b).

Spawning preceded the peak in irradiance during all years (fig. 35b).The initiation of gametogenesis and spawning were not sensitive to EC (fig. 36a) or

temperature (fig. 37a).Honker Bay - Station 433: The three environmental factors most important in determining the time

when Honker Bay animals became active, became ripe, and spawned were freshwater inflow, chlorophyll a concentration, and irradiance (figs. 38, 39, and 40). As active stage animals were not successfully sampled at this station (fig. 38a), only ripe and spawned animals will be discussed. The maximum percentage of ripe animals in the spring reproductive period coincided

with the peak freshwater inflow (1991 and 1992), or followed the increased freshwater inflow at

the beginning of the rainy season (1993 and 1994, fig. 38b). During the fall reproductive period, the maximum number of ripe animals followed the peak irradiance values in 1991-1993 (fig. 40) and coincided with a small increase in freshwater inflow in 1994 (fig. 38b). The environmental

12

cue for spawning was difficult to define for both the spring and fall reproductive cycles.Both gametogenesis and spawning were initiated over a broad range of EC values (0-

14000 jiSeimens/cm, fig. 41) and temperatures (fig. 42).Summary: Despite some differences, there were large similarities in the reproductive cycles of P amurensis at the locations examined (fig. 43). The timing of the reproductive cycles of P. amurensis in northern San Francisco Bay was most coincident with food availability at all of the

stations in the study. Gametogenesis started with the first increase in freshwater each year which

is coincident with increases in allochthonous food sources. Spawning was less consistent between stations but occurred with, or following increases in phytoplankton biomass, peaks in freshwater inflow, or irradiance at most stations which is indicative of peak growth in the autochthonous food sources.

Neither water temperature nor salinity could be seen to consistently influence the timing of the reproductive cycle. Although reproductive cycles seemed to be inversely correlated to the

temperature cycle during some periods, this correlation was most likely due to the cross correlation

of temperature and freshwater inflow. We conclude that temperature or change in temperature is not an important reproductive cue because the absolute value of temperature or change in

temperature during the reproductive events varied so much between years, stations, and the two seasonal reproduction cycles.

Reproductive cycles were distinctly seasonal except in Honker Bay and San Pablo Bay

animals, which exhibited near continuous reproduction with no apparent inactive stages during

most years. These animals also showed a lower percentage of inactive stage animals in the years in which reproductive activity wasn't continuous than did the populations at the other locations.

Condition and Reproduction

The condition index is calculated for animals of one shell length (15 mm) and should reflect

weight losses and gains due to reproductive activity in addition to somatic tissue (all non-

reproductive tissue) losses and gains. However, because condition is determined from a pooled sample of many animals, it may contain animals in various reproductive stages at the stations where animals have asynchronous spawning. Therefore, changes in condition that coincide with

reproductive activity, weight gain during gametogenesis, and weight loss during the spawning and spent stages, will be discussed for synchronous spawning populations only. At these stations, the

speed with which animal weight rebounds following spawning, and the amount of weight gained

during gamete development, is dependent on the balance between energy intake (that is food consumption) and metabolic requirements. Stressors, such as contaminants can affect the supply

13

side of this balance by inhibiting feeding rates and can influence the demand side by increasing metabolic rate. Thus when there is little weight gain during late gametogenesis for synchronously spawning populations, it is assumed that the animal is metabolizing somatic tissue (for example glycogen and lipid stores as well as structural tissue) in order to develop the reproductive tissue. Similarly, when there is little weight loss following spawning in synchronously spawning

populations, it can be assumed that there was sufficient food relative to the animals metabolic needs to replace the loss in weight due to the released gametes with new reproductive tissue or new

somatic tissue. Finally, if condition is stable for populations which spawn asynchronously, this

pattern for condition may confirm that spawning in this population is asynchronous. San Pablo Bay - Station 12.5: Condition was not consistently related to reproduction (fig. 44) in San Pablo Bay animals. Although there were periods of weight gain coincident with animals

becoming ripe in spring of 1993 (fig. 44b) there were many of times when the expected weight

losses and gains did not occur, e.g. the loss in weight in early 1992 and 1994 that was coincident with animals becoming ripe (fig. 44b). As noted earlier, this population asynchronously spawned

except in early 1993 and possibly in 1994 (fig. 13), and therefore the lack of correspondence

between reproductive activity and condition was not unexpected.Carquinez Strait- Station 8.1: Carquinez Strait animals spawned synchronously and condition and

reproductive stage were related in most years (fig. 45). Animals in 1994 had the highest condition

values and the largest post-spawning rebounds. In 1992, there was relatively little change in condition during the reproductive cycle. This population was synchronously spawning in 1992 (fig. 14) so this low and relatively stable condition may mean that these animals were scavenging somatic tissue to produce reproductive tissue, but were able to quickly regain weight after

spawning.

Suisun Bay - Station 6.1: Condition corresponded to reproductive stage in early 1991 in San

Pablo Bay animals, but there was less correspondence after that date (fig. 46). We have few data

points in 1993 and 1994 but the few points available indicate that maximum condition was seen in 1994, which was the only year when animals were synchronously spawning at this location Chipps Island- Station 4.1: Condition in Chipps Island animals was, on average, higher in 1993 and 1994 than in previous years (fig. 11) and varied greatly between seasons in all years of the study (figs. 47a and 47b). Changes in condition did not always correspond to changes in the

reproductive state of the animals which is expected in a population which asynchronously spawned

in all years of the study.Honker Bay - Station 433: Condition values were stable from 1991 through early 1993, due at

least in part to the strong asynchrony in spawning at this station, and much more seasonally

14

varying and larger in late 1993 and early 1994 (fig. 48). The data for late 1993 and early 1994 show a good correspondence between condition and reproduction with animals gaining substantial weight during reproductive development and losing weight at spawning (fig. 48). The post- spawning condition in 1993 was similar to the average condition seen in 1991 and 1992. Summary: Condition was inversely related to the cadmium content of animals; San Pablo Bay animals had the highest condition and those in Honker Bay had the lowest condition. Within this

condition gradient, animal condition was usually related to reproductive stage with animals

decreasing condition at spawning and increasing condition with developing gametes in those

populations that spawned synchronously. The strongest relationships between reproductive state

and condition and the largest post-spawning condition rebound were seen in 1993 and 1994 when the food supply was greatest.

Condition either varied very little (for example Honker Bay animals in 1991-1992) or

without a relationship to reproductive cycles at stations with asynchronously spawning animals.

The increase in condition during some years at these stations may have been due to an increase in condition during one or all of the reproductive stages or due to an increase in somatic tissue

weight. One of these periods, 1993, coincided with an increase in food, and thus both

reproductive and somatic tissue may have benefitted by the extra food available.

Reproductive Cycle and Cadmium Concentration

Spawning was asynchronous in animals from Honker Bay and Chipps Island in all years and in Suisun Bay in animals in 1991 through 1993 (figs. 49d, 49e, and 49f). Cadmium concentration and content had a downstream gradient which was consistent with this pattern of spawning synchrony: cadmium content was highest at the two landward sites and highest in 1991- 1993 in Suisun Bay (fig. 9). Cadmium content may be best used for this analysis because content

is not affected by condition if it is assumed that the reproductive products assimilate little trace

metal relative to somatic tissue. Because concentration values are normalized by condition, and

reproductive stage does affect condition, both condition and concentration values may shown smaller seasonal fluctuations in asynchronous populations. The consistent pattern between

cadmium content and spawning asynchrony may indicate that there is some threshold of cadmium

above which animals are either unable to interpret spawning cues or unable to control spawning. This hypothesis is consistent with the findings of Kluytmans et al. (1988) who found that

cadmium had a stimulating effect on the spawning ofAfytilus edulis in laboratory experiments.

The asynchronous spawning of animals in the spring of 1993 and 1994 in San Pablo Bay

occurred when cadmium levels were well below the threshold level suggested by data at the

15

upstream stations (figs. 8 and 9). Therefore, some over factor, possibly seasonal peaks in cadmium concentration which were not examined in this study or increased concentrations of selenium which is known to be elevated in these areas (Luoma, unpublished data), may be affecting the spawning synchrony of these animals during some years. It is not possible to determine what caused this change in reproductive pattern based on our present data collection, but

ongoing work on cadmium and selenium tissue burdens in this area of the bay by S.N. Luoma

may help.

ConclusionsI. The number of reproductive cycles in P. amurensis during each year and the time spent ininactive and early gametogenic stages is a function of food availability.

n. Asynchrony in spawning occurred at the three locations with the highest cadmium content.

ffl. Change in condition may be a function of food, spawning synchrony, and cadmiumconcentration:

Condition decreases with increasing cadmium content (figs. 9 and 10).

Condition changes very little or erratically in populations with asynchronous spawning.IV. Studies on reproductive cycles in P. amurensis in northern San Francisco Bay show promise in determining ecosystem effects of trace metals. Although P. amurensis is not an important economic species in the bay, the asynchronous spawning of these animals is a cause of concern.

The long term effects of a confused spawning cue on a less opportunistic species might be devastating. This in situ measure of the effect of a contaminant on an organism is the first that has been reported in San Francisco Bay.V. Studies of this kind require multiple years of data in order to interpret the many environmental

factors.

16

References

Alpine, A.E. and Cloern, I.E., 1992, Trophic interactions and direct physical effects control

phytoplankton biomass and production in an estuary: Limnology and

Oceanography, v. 37, p. 946-955.

Brown, C. and Luoma, S.N., 1995, Use of the euryhaline bivalve Potamocorbula amurensis as a

biosentinel species to assess trace metal contamination in San Francisco Bay: Marine Ecology Progress Series, v. 124, p. 129-142.

Caffrey, J.M., Cole, B.E., Cloern, I.E., Rudek, J.r., Tyler, A.C., and Jassby, A.D., 1994,

Studies of the San Francisco Bay, California, estuarine ecosystem: pilot regional

monitoring results, 1993: U.S. Geological Survey Open-File Report 94-82,411

PP

Carlton, J. T., Thompson, J.K., Schemel, L.E., and Nichols, F.H., 1990, Remarkable invasion of San Francisco Bay (California, USA) by the Asian clam Potamocorbula

amurensis. I. Introduction and dispersal: Marine Ecology Progress Series, v.66, p. 81-94.

Cloern, I.E., 1987, Turbidity as a control on phytoplankton biomass and productivity in estuaries:

Continental Shelf Research, v. 7, p. 1367-1381.

Cloern, I.E., Cole, B.E., Wong, R.L.J., and Alpine, A.E., 1985, Temporal dynamics of estuarine phytoplankton: a case study of San Francisco Bay: Hydrobiologia, v.l 29, p. 153-176.

Cole, B.E., Thompson, J.K., and Cloern, J.E., 1992, Measurement of filtration rates by infaunal

bivalves in a recirculating flume: Marine Biology, v. 113, p. 219-225.

Conomos, T.J.., Smith, R.E., and Gartner, J.W., 1985, Environmental setting of San Francisco Bay: Hydrobiologia, v. 129, p. 1-12.

Edmunds, J.L., Cole, B.E., Cloern, I.E., Caffrey, J.M., Jassby, A.D., 1995, Studies of the San

Francisco Bay, California, estuarine ecosystem: pilot regional monitoring results,

17

1994: U.S. Geological Survey Open-File Report 95-378, 436 pp.

Hager, S. W. and Schemel, L.E., 1996, Dissolved inorganic nitrogen, phosphorus, and silicon in South San Francisco Bay: I. Major factors affecting distributions: in San Francisco

Bay: The Ecosystem, J.T. Hollibaugh, editor, Pacific Division - American

Association for the Advancement of Science, San Francisco, in press.

Kluytmans, J.H., Brands, F., and Zandee, D.I., 1988, Interactions of cadmium with thereproductive cycle of Mytilus edulis L.: Marine Environmental Research, v. 24, p. 189- 192.

Nichols, F.H., Thompson, J.K., and Schemel, L.E., 1990, Remarkable invasion of San

Francisco Bay (California, USA) by the Asian clam Potamocorbula amurensis. 2.

Displacement of a former community: Marine Ecology Progress Series, v. 66, p. 95-101

Parchaso, F., 1993, Seasonal reproduction of Potamocorbula amurensis in San Francisco Bay,

California: M.A. thesis, San Francisco State University, 79p.

Rosenblum, S., 1981, The spawning cycle of Mya arenaria in San Francisco Bay: M.S. thesis,

San Francisco State University, 54p.

Wienke, S.M., Cole, B.E., Cloern, I.E., and Alpine, A.E., 1992, Plankton studies in San Francisco Bay, Xin. Chlorophyll distributions and hydrographic properties in San

Francisco Bay, 1991: U.S. Geological Survey Open-File Report 92-158, 116p.

Wienke, S.M., Cole, B.E., Cloern, I.E., and Alpine, A.E., 1993, Plankton studies in San Francisco Bay, Xin. Chlorophyll distributions and hydrographic properties in San Francisco Bay, 1992: U.S. Geological Survey Open-File Report 92-158, 175p.

18

Tables 1 and 2.

19

Table 1. Collection Stations. Latitude, Longitude and depth (meters) at mean lower low water.

Station number Station Name____Lattitude____Longitude____Depth (m)12.5 SanPabloBay 38 02.43' N 12218.85' W 6.7

8.1 Carquinez Strait 38 01.90' N 122 08.40'W 14.9

6.1 SuisunBay 38 03.70' N 122 02.20'W 9.8

4.1 Chipps Island 38 03.30' N 121.56.70' W 8.8

433 Honker Bay 38 04.23'N 121 56.03'W 2.5

Tabl

e 2.

C

olle

ctio

n da

tes

by s

tatio

n w

hen

no c

lam

s w

ere

avai

labl

e fo

r exa

min

atio

n.

8.1

Car

quin

ez S

trait

6.1

Suis

un B

ay4.

1 C

hipp

s Is

land

12.5

San

Pab

lo B

ay

433

Hon

ker B

ayD

ec-9

2 Ju

l-92

Jun-

91Fe

b-94

Ju

l-91

Jul-9

4 Se

p-92

Sep-

93

Jun-

92D

ec-9

2Fe

b-94

Jun-

94N

ov-9

4D

ec-9

4

Dec

-91

Jan-

92Fe

b-93

May

-93

Aug

-93

Mar

-94

Apr

-94

May

-94

Jun-

94Ju

l-94

Figures 1 through 49.

122*3? 1221* 122W

3PW -

Spoonbill Creek uinez CWpps Island

, Mallard Island

Figure 1. Map of study area including U.S.G.S. and D.W.R. (D6, D9, and DIO) stations.

Fre

shw

ater

In

flo

w

1982

-199

4

20000

o o CO 2 o 4-* o E 3

O

1500

0 --

1000

0 --

5000

--

090

Figu

re 2

. D

aily

fre

shw

ater

Inflo

w in

to n

orth

ern

San

Fran

cisc

o B

ay f

or w

ater

yea

rs 1

982-

1994

(O

ctob

er th

roug

h Se

ptem

ber)

. D

ata

is c

alcu

late

d by

Cal

ifor

nia

Dep

artm

ent o

f Wat

er R

esou

rces

as

net

del

at o

utfl

ow.

Mallard Island Surface Water Electrical Conductivity

18000 --

16000 --

14000 -

E 12000 -- ,0g 10000 -

I 8000 - " 6000 --

4000 --

2000 -

01990 1991 1992 1993 1994 1995

Figure 3a. Surface water electrical conductivity at California Department of Water Resources Mallard Island monitoring station.

Mallard Island Surface Water Temperature

24.00

20.00 --

16.00 --

12.00 -

8.00 -

4.001990 1991 1992 1993 1994 1995

Figure 3b. Surface water temperature at California Department of Water Resources Mallard Island monitoring station.

Martinez Surface Water Electrical Conductivity

1990 1991 1992 1993 1994 1995

Figure 4a. Surface water electrical conductivity at California Department of Water Resources Martinez monitoring station.

Martinez Surface Water Temperature

24.00

O

20.00 --

16.00 --

12.00 --

8.00 --

4.001990 1991 1992 1993 1994 1995

Figure 4b. Surface water temperature at California Department of Water Resources Martinez monitoring station.

Ch

loro

ph

yll

a

Pot

amoc

orbu

la a

mur

ensi

s po

pula

tion

esta

blis

hed

9094

Figu

re 5

. M

onth

ly o

r se

mi-

mon

thly

mea

sure

s of

chl

orop

hyll

a in

Sui

sun

Bay

. D

ata

from

Cal

ifor

nia

Dep

artm

ent o

f Wat

er R

esou

rces

Sta

tion

D8

(197

4-19

87)

and

U.S

. G

eolo

gica

l Su

rvey

sta

tion

5 (1

988-

1994

). Fi

gure

ada

pted

fro

m A

lpin

e an

d C

loer

n, 1

992.

Hyp

othe

tical

Fr

eshw

ater

Inf

low

, N

on-r

efra

ctor

y P

artic

ulat

e O

rgan

ic C

arbo

n, a

nd C

hlor

ophy

ll a

Figu

re 6

. H

ypot

hetic

al a

nnua

l (w

ater

yea

r) p

atte

rn o

f fre

shw

ater

inflo

w, n

on-r

efra

ctor

y pa

rticu

late

or

gani

c ca

rbon

and

chl

orop

hyll

a ba

sed

on H

ager

and

Sch

emel

(19

96)

and

U.S

.G.S

. his

toric

al d

ata

(unp

ublis

hed)

. R

elat

ive

mag

nitu

des

with

in th

e ye

ar fo

r eac

h pa

ram

eter

are

val

id b

ut re

lativ

e m

agni

tude

s be

twee

n pa

rticu

late

org

anic

car

bon

and

chlo

roph

yll a

var

y be

twee

n ye

ars

and

shou

ld n

ot b

e us

ed a

s re

lativ

e or

abs

olut

e va

lues

.

Cd Content1991-1994

0.14

0.12

0.1

0.088

0.06

0.04

0.02

0 -

!^ { Ii i ' '

I | |

12.5 8.1 6.1 4.1

Station

*

I

433

Figure 7. Cadmium content at all stations (1991-1994).

Cd Concentration1991-1994

12.0 -

10.0

8.0

e> w 6.0±L

4.0

2.0

o.o -

t

i i ' !12.5 8.1 6.1 4.1

Station

I

iiIi

433

Figure 8. Cadmium concentration at all stations (1991-1994).

0.12

0.10 --

0.08 -

§0.06 --

0.04 --

0.02 -

0.00

Cd Content Annual Average

1991 1992 1993 1994

Figure 9. Yearly average cadmium content at all stations.

Condition1991-1994

0.0500 -i

0.0450 -

0.0400 -

0.0350 -

0.0300 -

o>0.0250 -

0.0200 -

0.0150 -

0.0100 -

0.0050 -

0.0000 -

*»| *

ti i ii * i

12.5 8.1 6.1

Station

i I. Ai

4.1 433

Figure 10. Condition at all stations (1991-1994).

Average Condition

0.035 T

0.030 --

0.025

en

0.020 -

0.015 -

0.010

12.5

8.1

1991 1992 1993 1994

Figure 11. Average condition at all stations for 1991 through 1994. Averages not shown for 1993 and 1994 at station 6.1 and 1994 at station 433 due to incomplete data sets.

a.% Ripe and Spawn

% Ripe and Spawn

c.

15.00 -

10.00 -0

(0a:

5.00 -

0.00 -

Ripe/Spawn

asynchronous

synchronous

(\ ,/-\Figure 12. Hypothetical population showing a) cumulative percentages of ripe and spawning animals, b) percent ripe and spawning, and c) ratio of ripe/spawning animals showing synchrony in spawning.

100

% R

ipe,

Spa

wni

ng,

and

Spe

nt

San

P

ablo

(S

tatio

n 12

.5)

Figu

re 1

3. C

umul

ativ

e pe

rcen

t of a

nim

als

in ri

pe, s

paw

ning

and

spe

nt r

epro

duct

ive

stag

e at

sta

tion

12.5

.

%R

ipe,

Spa

wni

ng,

and

Spe

nt

Car

quin

ez S

trai

t (S

tatio

n 8.

1)10

0

o> (0 ->

cr> (0 5

O) is

(0 21 3 -j>

CL

0) (0

1 o zCO

T

-CN

J

Figu

re 1

4. C

umul

ativ

e pe

rcen

t of a

nim

als

in ri

pe, s

paw

ning

and

spe

nt r

epro

duct

ive

stag

e at

sta

tion

8.1.

100.

0

90.0

% R

ipe,

Spa

wni

ng,

and

Spe

nt

Suis

un B

ay (

Sta

tion

6.1)

CM

Figu

re 1

5. C

umul

ativ

e pe

rcen

t of a

nim

als

in ri

pe, s

paw

ning

and

spe

nt r

epro

duct

ive

stag

e at

sta

tion

6.1.

100

%R

ipe,

Spa

wni

ng,

and

Spe

nt

Chi

pps

Isla

nd (

Sta

tion

4.1)

Figu

re 1

6. C

umul

ativ

e pe

rcen

t of a

nim

als

in ri

pe, s

paw

ning

, and

spe

nt re

prod

uctiv

e st

age

at s

tatio

n 4.

1.

% R

ipe,

Spa

wni

ng,

and

Spe

nt

Hon

ker

Bay

(S

tatio

n 43

3)

<o

Figu

re 1

7 C

umul

ativ

e pe

rcen

t of a

nim

als

in r

ipe,

spa

wni

ng a

nd s

pent

repr

oduc

tive

stag

e at

sta

tion

433.

Freshwater Inflow and % Active San Pablo Bay (Station 12.5)

,...f\.........

1991 1992 1993 1994

Figure 18a. Freshwater inflow and % of animals in active reproductive stage (°) at station 12.5.

Freshwater Inflow and % Ripe San Pablo Bay (Station 12.5)

100

1991 1992 1993 1994

Figure 18b. Freshwater inflow and % of animals in ripe reproductive stage (°) at station 12.5.

Water Column Chlorophyll a and % Active San Pablo Bay (Station 12.5)

o J1991 1992 1993 1994

Figure 19a. Water column chlorophyll a (A ) and % of animals in active reproductive stage (°) at station 12.5.

Water Column Chlorophyll a and % Ripe San Pablo Bay (Station 12.5)

12

1991 1992 1993 1994

Figure 19b. Water column chlorophyll a (A ) and % of animals in active reproductive stage (°) at station 12.5.

Irradiance and %Active San Pablo Bay (Station 12.5)

60 -r

1991 1992 1993 1994

Figure 20a. Irradiance ( A ) and % of animals in active reproductive stage (°) station 12.5.

at

Irradiance and %Ripe San Pablo Bay (Station 12.5)

1991 1992 1993 1994

Figure 20b. Irradiance (A ) and % of animals in ripe reproductive stage (°) at station 12.5.

Salinity and %Active San Pablo Bay (Station 12.5)

30

0 -<

1991 1992 1993 1994

Figure 21a. Salinity ( A ) and % of animals in active reproductive stage (°) at station 12.5.

Salinity and %Ripe San Pablo Bay (Station 12.5)

30 100

£5?

1991 1992 1993

Figure 21b. Salinity (A ) and % of animals in ripe reproductive stage (°) at station 12.5.

Temperature and % Active San Pablo Bay (Station 12.5)

25

1991 1992 1993 1994

Figure 22a. Temperature station 12.5.

and % of animals in active reproductive stage (°) at

Temperature and % Ripe San Pablo Bay (Station 12.5)

25

1991 1992 1993 1994

Figure 22b. Temperature station 12.5.

and % of animals in ripe reproductive stage (°) at

Freshwater Inflow and % Active Carquinez Strait (Station 8.1)

100

1991 1992 1993 1994

Figure 23a. Freshwater inflow and % of animals in active reproductive stage (°) at station 8.1.

Freshwater Inflow and % Ripe Carquinez Strait (Station 8.1)

1991 1992 1993 1994

Figure 23b. Freshwater inflow and % of animals in ripe reproductive stage (°) at station 8.1.

Water Column Chlorophyll a and % Active Carquinez Strait (Station 8.1)

10 100

1991 1992 1993 1994

Figure 24a Water column chlorophyll a ( A ) and % of animals in active reproductive stage (°) at station 8.1.

Water Column Chlorophyll a and % Ripe Carquinez Strait (Station 8.1)

o

1991 1992 1993 1994

Figure 24b. Water column chlorophyll a ( A ) and % of animals in ripe reproductive stage (°) at station 8.1.

Irradiance and % Active Carquinez Strait (Station 8.1)

60

1991 1992 1993 1994

Figure 25a. Irradiance ( A ) and % of animals in active reproductive stage (°) at station 8.1

Irradiance and % Ripe Carquinez Strait (Station 8.1)

60

1991 1992 1993 1994

Figure 25b. Irradiance ( A ) and % of animals in ripe reproductive stage (°) at station 8.1

EC and % Active Carquinez Strait (Station 8.1)

1991 1992 1993 1994

Figure 26a. EC (A ) and % of animals in active reproductive stage (°) at station 8.1.

EC and % Ripe Carquinez Strait (Station 8.1)

100

1991 1992 1993OOOOCDO-J- 0

1994

Figure 26b. EC (A) and % of animals in ripe reproductive stage (°) at station 8.1.

Temperature and % Active Carquinez Strait (Station 8.1)

25

1991 1992 1993 1994

Figure 27a. Temperature (A) and % of animals in active reproductive stage (°) at station 8.1.

Temperature and % Ripe Carquinez Strait (Station 8.1)

25

1991 1992 1993 1994

Figure 27b. Temperature (A ) and % of animals in ripe reproductive stage (°) at station 8.1.

Freshwater Inflow and % Active Suisun Bay (Station 6.1)

5000

1991 1992 1993 1994

Figure 28a. Freshwater inflow and % of animals in active reproductive stage (°) at station 6.1.

Freshwater Inflow and % Ripe Suisun Bay (Station 6.1)

5000

1991 1992 1993 1994

Figure 28b. Freshwater inflow and % of animals in ripe reproductive stage (°) at station 6.1.

16

Water Column Chlorophll a and % Active Suisun Bay (Station 6.1)

1991 1992 1993 1994

Figure 29a. Water column chlorophyll a (A ) and % of animals in active reproductive stage (°) at station 6.1.

Water Column Chlorophyll a and % Ripe Suisun Bay (Station 6.1)

1991 1992 1993 1994

Figure 29b. Water column chlorophyll a ( A ) and % of animals in ripe reproductive stage (°) at station 6.1.

Irradiance and % Active Suisun Bay (Station 6.1)

60.0 -r

1991 1992 1993 1994

Figure 30a. Irradiance (A ) and % of animals in active reproductive stage (°) at station 6.1.

Irradiance and % Ripe Suisun Bay (Station 6.1)

60.0

0.01991 1992 1993 1994

Figure 30b. Irradiance (A ) and % of animals in ripe reproductive stage (°) at station 6.1

EC and % Active Suisun Bay (Station 6.1)

100

+3 O

UJ

1991 1992 1993 1994

Figure 3 la. EC (A ) and % of animals in active reproductive stage (°) at station 6.1.

EC and % Ripe Suisun Bay (Station 6.1)

20000 -

18000 --

^ 16000 -

I 14000 -

e 12000 --0)

I 10000 - «5 8000 -j-

6000

4000

2000 +

0

1991 1992 1993 1994

Figure 3 Ib. EC (A ) and % of animals in ripe reproductive stage (°) at station 6.1.

Temperature and % Active Suisun Bay (Station 6.1)

100

1991 1992 1993 1994

Figure 32a. Temperature ( A ) and % of animals in active reproductive stage (°) at station 6.1.

Temperature and % Ripe Suisun Bay (Station 6.1)

25

1991 1992 1993 1994

Figure 32b. Temperature (A ) and % of animals in ripe reproductive stage (°) at station 6.1.

Freshwater Inflow and % Active Chipps Island (Station 4.1)

1991 1992 1993 1994

Figure 3 3 a. Freshwater inflow and % of animals in active reproductive stage (°) at station 4.1.

Freshwater Inflow and % Ripe Chipps Island (Station 4.1)

1991 1992 1993 1994

Figure 33b. Freshwater inflow and % of animals in ripe reproductive stage (°) at station 4.1.

Water Column Chlorophyll a and % Active Chipps Island (Station 4.1)

1991 1992 1993 1994

Figure 34a. Water column chlorophyll a (A ) and % of animals in active reproductive stage (°) at station 4.1.

Water Column Chlorophyll a and % Ripe Chipps Island (Station 4.1)

1991 1992 1993 1994

Figure 34b. Water column chlorophyll a ( A ) and % of animals in ripe reproductive stage (°) at station 4.1.

60.00

Irradiance and % Active Chipps Island (Station 4.1)

-co-

o.oo -i1991 1992 1993 1994

Figure 35a. Irradiance ( A ) and % of animals in active reproductive stage (°) at station 4.1.

Irradiance and % Ripe Chipps Island (Station 4.1)

60.00 1 100

0)o.

0.001991 1992 1993 1994

Figure 35b. Irradiance (A ) and % of animals in ripe reproductive stage (°) at station 4.1.

EC and % Active Chipps Island (Station 4.1)

vr

IO UJ

1991 1992 1993 1994

Figure 36a. EC (A ) and % of animals in active reproductive stage (°) at station 4.1.

EC and % Ripe Chipps Island (Station 4.1)

1991 1992 1993 1994

Figure 36b. EC (A ) and % of animals in ripe reproductive stage (°) at station 4.1.

Temperature and % Active Chipps Island (Station 4.1)

25

1991 1992 1993 1994

Figure 37b. Temperature ( A ) and % of animals in active reproductive stage (°) at station 4.1.

Temperature and % Ripe Chipps Island (Station 4.1)

1991 1992 1993 1994

Figure 37b. Temperature ( A ) and % of animals in ripe reproductive stage (°) at station 4.1.

Freshwater Inflow and % Active Honker Bay (Station 433)

5000 --

4500 -

4000 --

1991 1992 1993 1994

Figure3 8a. Freshwater inflow and % of animals in active reproductive stage (°) at station 433.

Freshwater Inflow and % Ripe Honker Bay (Station 433)

1991 1992 1993 1994

Figure 38b. Freshwater inflow and % of animals in ripe reproductive stage (°) at station 433.

Water Column Chlorophyll a and % Ripe Honker Bay (Station 433)

a 8 .2

1991 1992 1993 1994

Figure 39. Water column chlorophyll a (A ) and % of animals in ripe reproductive stage (°) at station 433.

Irradiance and % Ripe Honker Bay (Station 433)

60.0

1991 1992 1993 1994

Figure 40. Irradiance ( A ) and % of animals in ripe reproductive stage (°) at station 433.

EC and % Ripe Honker Bay (Station 433)

16000.00

14000.00

12000.00 -po

10000.00 £

8000.00

6000.00

4000.00

2000.00

0.00

o> '55

IoIU

1991 1992 1993 1994

Figure 41. EC ( A ) and % of animals in ripe reproductive stage (°) at station 433.

Temperature and % Ripe Honker Bay (Station 433)

25.00

1991 1992 1993 19940.00

Figure 42. Temperature ( A ) and % of animals in ripe reproductive stage (°) at station 433.

San Pablo Bay100

£ 50 -- 55

100* &

soif* * in A <* <*] < «*<*

Carquinez Strait <

y\

Suisun Bay

100.0

&£ 50. 5?

V \ » \.0 -/ \ r \r V \0.0 -I »*-*<»<*! *-»<«*'

Chipps Island100

8.£ 50

,v VI/ \

' \ Ik

Honker Bay100.0

£ 50.0 -- 55

0.0

/A X \,* ...........A -/ A/v\/ ]

1991 1992 1993 1994

Figure 43. Percent of ripe animals at all stations.

Condition and %Active San Pablo Bay (Station 12.5)

1991 1992 1993 1994

Figure 44a. Condition index for 15mm long animal (A ) and % of animals in active reproductive stage (°) at station 12.5.

Condition and %Ripe San Pablo Bay (Station 12.5)

1991 1992 1993 1994

Figure 44b. Condition index for 15mm long animal ( A) and % of animals in ripe reproductive stage (°) at station 12.5.

Condition Index and % Active Carquinez Strait (Station 8.1)

g 0.0295 -

0.0245

1991 1992 1993 1994

Figure 45a. Condition index for 15mm long animal (A ) and % of animals in active reproductive stage (°) at station 8.1.

Condition Index and % Ripe Carquinez Strait (Station 8.1)

100

12 0.0245 -o0 0.0195

25

1991 1992 1993 1994

Figure 45b. Condition index for 15mm long animal ( A ) and % of animals in ripe reproductive stage (°) at station 8.1.

Condition Index and % Active Suisun Bay (Station 6.1)

0.0280

0.0260 --

0.0240 --

1991 1992 1993 1994

Figure 46a. Condition index for 15mm long animal (A ) and % of animals in active reproductive stage (°) at station 6.1.

Condition Index and % Ripe Suisun Bay (Station 6.1)

1991 1992 1993 1994

Figure 46b. Condition index for 15mm long animal ( A ) and % of animals in ripe reproductive stage (°) at station 6.1.

Condition Index and % Active Chipps Island (Station 4.1)

0.0280 --

0.0260 -

0.0240 --

1991JUUUUUUU

1992 1993 1994

Figure 47a. Condition index for 15mm long animal (A ) and % of animals in active

reproductive stage (°) at station 4.1.

Condition Index and % Ripe Chipps Island (Station 4.1)

0.0280 i

0.0260 --

0.0240 --

1991 1992 1993 1994

Figure 47b. Condition index for 15mm long animal ( A ) and % of animals in ripe reproductive stage (°) at station 4.1.

Condition Index and % Ripe Honker Bay (Station 433)

1991 1992 19930.0000

1994

Figure 48. Condition index for 15mm long animal (A ) and % of animals in ripe reproductive stage (°) at station 433.

a. Ripe/Spawn Hypothetical Population

15 -

12 -

.2 9 -CO** O -

3 -

0 -

asynchronous

synchronous

/v , IV,A

Ripe/Spawn San Pablo Bay

15 -j

12 -

.29-**(0fib £*

:;.K I| I I

i ^jvN ,. A.1991 1992 1993 1994

c Ripe/SpawnCarquinez Strait

4 e . 1 w

12 -

.2 9COfi£ C

3 -

0 -

iIA A ,./x ,A

i

d Ripe/Spawn Suisun Bay

15 -

12 -

o 9 Hwfib C

3 -

0 -

:

i

A A iA/V ,/V , )l ,/v I

e. Ripe/Spawn Chipps Island

15

12 -

o 9 -(0

D '

3 -

0 J

I:

-/I A iIUA , /\ A |

f Ripe/SpawnHonker Bay

15 -

12 -

.2 9 "

ftr ^

" D -

3 -

0 -

iA A A KIV\ I \A AjWo daia

1991 1992 1993 1994

Figure 49. Synchrony of spawning in hypothetical population and populations in this study.

Appendix I.

Station 8.1 Carquinez Strait

Date Length Sex Stage7-Jan-91 6.8

11.511.010.511.811.516.815.115.514.212.012.89.96.8

15.6

7-Feb-91 12.58.3

13.114.615.813.76.59.5

16.117.019.811.25.5

16.012.4

13-Mar-91 16.115.817.014.613.510.814.08.5

10.89.0

16.012.816.812.914.8

112222112211202

211211112111111

112212122122211

233323233333313

433444442343423

333333344453443

Date Length Sex Stage12-Apr-91

8-May-91

5-Jun-91

9.511.2

8.98.5

11.811.29.8

13.411.913.213.912.814.7

9.310.113.814.913.58.4

14.513.111.915.112.912.913.57.3

15.1

17.111.116.58.2

11.816.0

9.814.516.89.9

13.214.59.1

10.5

2211112221112

212222121111111

22221112211211

3334333333334

335433333333353

35455555555535

Sex: 1«=Mate, 2»Femate. Stage: 1« Inactive, 2«active, 3=Ripe, 4=Partial Spawn, 5*Spent, 0=Undefmed (See Text)A2

Station 8.1 Carquinez Strait

Date Length Sex StageA 4 |||| Q4 7 *l

7.28.57.36.2

11.712.111.711.912.114.214.515.116.215.8

2-Aug-91 17.216.28.2

11.111.116.017.117.917.410.910.110.811.9

12-Sep-91 11.311.114.311.412.117.86.69.77.37.3

19.614.915.114.17.1

000000000110121

0102221020001

000002000000000

111111151555543

5455554555115

111115111111111

Date Length Sex Stage1-Oct-91

19-Nov-91

10-Dec-91

7-Jan-92

10.211.213.114.014.111.615.911.412.817.116.116.918.516.916.8

14.415.610.011.711.4

9.115.610.710.8

17.718.914.412.611.29.47.87.56.5

13.3

17.416.415.213.512.212.011.610.19.79.4

001200200001001

112101112

2222100212

2112221121

115511511115155

025552225

1112211212

3333332222

Sex: 1«Mate, 2*Female. Stage: 1«Inactive, 2«actlve, 3«Ripe, 4«Partial Spawn, 5*Spent, (^Undefined (See Text)A3

Station 8.1 Carquinez Strait

Date Length Sex Stage5-Feb-92

4-Mar-92

8-Apr-92

28-May-92

14.714.614.513.412.611.710.210.18.38.0

18.416.015.214.312.712.412.212.111.510.2

16.515.615.314.514.211.210.910.18.48.1

20.616.214.213.911.29.99.29.18.2

16.4

1211211121

2121221111

1211112211

2221110001

2333222322

4343333333

3345553455

5554555555

Date Length Sex Stage16-Jun-92

28-JUI-92

22-Aug-92

29-Sep-92

19.217.716.715.313.012.710.310.06.96.5

21.419.418.516.112.712.312.010.010.09.6

19.217.416.114.113.812.511.19.96.75.1

18.718.117.014.214.112.412.07.06.85.5

1211110100

0012022000

1201211000

1122222001

5545451111

1115112111

2211222111

2222122112

Sex: 1«Male,2=Female. Stage: 1« Inactive, 2=active, 3=Ripe, 4=Partial Spawn, 5«Spent, 0=Undef»ned (See Text)

A4

Station 8.1 Carquinez Strait

Date Length Sex Stage14-Oct-92

2-NOV-92

27-Jan-93

25-Feb-93

20.319.318.616.815.114.813.813.713.012.0

17.016.614.614.111.711.68.87.36.74.6

10.510.65.25.5

16.012.79.07.7

14.78.9

8.810.013.08.38.27.5

18.79.2

2121122021

2112011010

2201021022

21112212

2222222122

2222122020

2203033022

33333333

Date Length Sex Stage30-Mar-93

15-Apr-93

12-May-93

15-Jun-93

9.86.37.57.09.4

10.210.2

5.16.19.5

8.511.410.48.9

10.510.910.514.29.4

11.3

8.917.312.46.69.28.7

16.68.9

14.212.3

12.113.714.610.714.012.915.518.717.3

1101111101

2122222222

2121221121

221122112

3303333303

3333333333

4344443444

434434433

Sex: 1«Male,2=Femate. Stage: 1« Inactive, ^active, 3=Ripe,4«Partial Spawn, 5=Spent, (^Undefined (See Text)

A5

Station 8.1 Carquinez Strait

Date Length Sex Stage13-Jul-93

10-Aug-93

8-Sep-93

6-Oct-93

10.813.113.415.312.613.515.314.617.217.7

14.316.720.016.216.813.617.418.114.414.9

14.014.214.512.812.916.114.820.117.518.0

19.819.617.517.015.613.69.29.39.1

12.3

1111111111

0210020011

0000001010

0020000020

5555545535

5555555555

1111115555

1

111

Date Length Sex StageS-Nov-93

7-Dec-93

19- Jan-94

16-Feb-94

19.217.717.116.714.313.712.912.88.37.3

9.111.011.2

1.415.115.115.517.918.319.4

3.94.05.16.5

15.311.2

5.36.8

10.711.113.45.05.96.14.85.0

0001000100

0121111212

100122

0021210102

1112111211

1222222222

200222

0023301202

Sex: 1«Mate,2«Female. Stage: 1« Inactive, 2«actlve,3*Ripe,4«Partial Spawn, 5*Spent, (^Undefined (See Text)A6

Station 8.1 Carquinez Strait

Date Length Sex Stage6-Mar-94

19-Apr-94

17-May-94

15-Jun-94

6.010.06.06.07.0

16.115.65.2

16.79.8

18.916.3

8.111.65.48.8

13.28.87.2

11.0

6.04.27.2

11.09.1

12.912.814.511.317.4

8.36.8

13.88.19.5

12.37.05.1

14.2

1111122022

2211001121

0001121122

000012000

4233333034

4544554544

5055555555

111155111

Date Length Sex Stage28-Jul-94

30-Aug-94

27-Sep-94

26-Oct-94

7.37.69.99.5

13.815.115.113.1

15.28.0

11.610.06.71.6

11.418.48.2

17.2

18.213.514.919.918.410.15.9

11.48.5

19.23.68.09.08.7

10.913.012.014.8

00002000

1120000111

100200000

200222111

11112111

2121111112

111211111

211222222

Sex: 1»Mate, 2=Femate. Stage: 1« Inactive, 2«active, 3*Ripe, 4*Partial Spawn, 5-Spent, 0*Undefined (See Text)A7

Station 6.1 Suisun Bay

Date Length Sex Stage7-Jan-91 9.0

6.58.0

14.111.55.2

19.17.0

10.616.022.719.7

8.614.5

7-Fel>91 25.726.425.59.97.18.0

10.39.0

10.511.015.716.714.517.119.5

12-Mar-91 17.812.517.816.116.817.317.519.717.820.419.918.8

00212022212122

112222221121111

122221121112

11122132122323

345344343333333

333333335553

Date Length Sex Stage12-Apr-91

8-May-91

5-Jun-91

19.518.99.86.9

10.512.58.8

16.110.2

5.89.77.7

14.114.5

20.918.217.814.510.59.2

13.810.512.212.8

19.219.911.814.212.511.112.814.29.9

17.0

21111122122222

1211111111

2111111111

53344343344433

5434554344

4555555555

Sex: 1«Mate, 2=Femate. Stage: 1« Inactive, 2«active, 3»Ripe, 4»Partial Spawn, 5=Spent, 0«Undeflned (See Text)

A8

Station 6.1 Suisun Bay

Date Length Sex Stage11-Jul-91

2-Aug-91

12-Se|>91

1-Oct-91

11.214.112.27.2

15.011.011.19.59.8

18.919.821.021.916.8

12.114.812.015.813.215.514.016.014.812.89.0

12.710.811.6

10.89.2

12.96.96.78.18.28.2

11.210.618.917.2

13.920.220.125.213.1

01111002011210

02000002000000

000001000000

12111

25555554545555

53555555555515

111111

55555

Date Length Sex Stage19-NOV-91

10-Dec-91

7-Jan-92

5-Feb-92

9.911.311.914.114.515.116.016.321.423.3

20.719.618.617.215.514.714.113.510.7

20.918.715.815.013.512.812.78.57.8

13.2

10.111.913.814.214.915.115.316.8

0012121111

212222110

2222222212

12122221

1121222112

222222221

3332332223

33333333

Sex: 1-Male, 2-FemaJe. Stage: Inactive, 2*active, 3«RJpe, 4*Partial Spawn, 5*Spent, 0=Undefined (See Text) A9

Station 6.1 Suisun Bay

Date Length Sex Stage4-Mar-92

8-Apr-92

28-May-92

16-Jun-92

21.220.115.815.014.912.912.812.59.9

23.016.113.613.212.18.99.07.57.1

19.719.616.717.715.515.312.610.5

8.17.8

22.819.019.017.813.413.112.411.17.95.9

211121111

221121211

1111111111

1010121110

333333344

334334444

4355453555

5555555551

Date Length Sex Stage22-Aug-92

29-Sep-92

14-Oct-92

2-Nov-92

20.117.816.215.715.112.812.511.58.68.4

22.721.521.320.316.815.514.314.112.7

20.817.816.911.811.510.69.27.67.2

20.416.815.515.514.713.814.111.8

0211211001

110211211

221111100

11111111

1555555115

555555553

555555511

45554455

Sex: 1«Mate, 2-Femate. Stage: 1« Inactive, 2«acttve, 3«Ripe, 4«Partial Spawn, 5*Spent, (^Undefined (See Text)A 10

Station 6.1 Suisun Bay

Date Length Sex Stage2-Dec-92

27-Jan-93

25-Feb-93

30-Mar-93

15-Apr-93

20.87.0

16.812.86.28.2

11.112.117.516.2

12.410.512.4

121.012.08.0

15.010.016.9

14.210.110.513.517.316.715.418.216.7

8.37.5

10.66.1

5.15.3

17.3

1012012112

122212211

200222222

1121

011

2022052212

222222223

300333322

2222

023

Date Length Sex Stage12-May-93

15-Jun-93

19-Jul-93

10-Aug-93

8-Sep-93

6-Oct-93

6.911.47.35.8

16.111.217.011.58.58.5

10.714.315.112.512.811.8

7.59.0

16.215.96.8

12.3

18.317.213.814.014.114.69.7

12.816.3

13.4

21.122.223.819.416.910.820.614.017.9

0100122212

212111

121101

122111111

1

112222121

0300343443

433333

555404

455455555

5

555555555

Sex: 1*Mate,2*Female. Stage: 1« Inactive, 2-active, 3-Ripe, 4»Partlal Spawn, 5«Spent, 0-Undefined (See Text)A11

Station 6.1 Suisun Bay

Date Length Sex Stage ____Date Length Sex Stage8-Nov-93

7-Dec-93

19- Jan-94

16-Feb-94

6-Mar-94

19- Apr-94

17-May-94

15-Jun-94

27-Sep-94

3.818.5

16.710.410.92.8

19.7

17.6

5.1

13.814.75.8

13.814.820.6

7.87.5

23.720.0

4.5

4.121.9

4.5

11.113.518.1

02

22101

1

0

211

111

01111

020

112

05

22202

3

0

344

453

05444

040

155

Sex: 1-Mate, 2»Femate. Stage: 1« Inactive, 2»ac«ve, 3»Ripe, 4»Partial Spawn, 5«Spent, (^Undefined (See Text)A 12

Station 4.1 Chipps Island

Date Length Sex Stage8-Jan-91

6-Feb-91

12-Mar-91

12-Apr-91

7.77.89.49.9

11.111.416.922.723.024.1

4.56.87.57.58.1

20.123.524.225.4

6.37.19.6

12.119.715.820.521.323.025.9

27.324.121.611.010.68.8

1121222212

212

1122222122

121121

3333333333

333333333

4433333333

333334

Date Length Sex Stage8-May-91

1-Aug-92

12-Sep-91

1-Oct-91

19-Nov-91

10-Dec-91

7.98.48.5

16.917.819.323.123.125.525.9

6.58.19.1

12.713.2

26.023.417.015.815.114.211.2

9.17.1

13.120.223.123.525.826.026.6

4.85.25.56.26.49.8

11.914.1

19.26.5

1111122212

10112

211212111

1221121

00102111

21

4443334334

30434

344454555

5555545

11505545

25

Sex: 1*Mate,2*Femate. Stage: 1* Inactive, 2«active( 3»Ripe, 4«Paitlal Spawn, 5«Spentt 0*Undefined (See Text)A13

Station 4.1 Chipps Island

Date Length Sex Stage7-Jan-92

5-Feb-92

4-Mar-92

8-Apr-92

28-May-92

16-Jun-92

25.115.113.913.512.011.711.511.010.98.5

8.28.68.6

13.916.114.916.222.222.127.9

13.512.210.816.18.5

24.217.325.2

9.414.616.022.5

17.013.17.9

29.315.913.411.2

1111122122

2221222111

21142111

2221

100

1101

3334334334

4343343343

54354444

5553

550

5515

Date Length Sex Stage28-Jul-92

22-Aug-92

14-Oct-92

3-NOV-92

2-Dec-92

17.712.414.810.78.8

10.515.912.5

16.29.6

13.29.4

11.618.1

9.711.011.112.816.216.315.917.219.520.5

5.710.413.714.318.0

18.416.015.011.812.816.813.615.710.814.8

11000022

110020

0000102120

01220

1121221122

551111

1

1111111111

12211

2222222212

Sex: 1=Mate, 2=Femate. Stage: 1= Inactive, 2=activ«, 3=Ripe,4=Partial Spawn, 5=Spcnt,0= Undefined (See Text)A 14

Station 4.1 Chipps Island

Date Length Sex Stage27-Jan-93

25-Feb-93

30-Mar-93

15-Apr-93

12-May-93

10.816.511.312.217.013.58.0

11.210.812.4

8.911.511.912.013.613.715.216.216.718.5

13.0

6.611.812.012.212.512.913.114.017.3

4.58.1

10.211.015.515.9

1222111121

1121211112

1

112122122

212112

3332223333

3323333333

3

333333333

323333

Date Length Sex Stage

15-Jun-93 11.0 1

19-Jul-93 19.217.717.516.214.87.96.96.0

10-Aug-93 17.116.714.96.24.4

. 6-OCI-93 19.118.917.817.717.417.417.216.713.3

8-NOV-93 19.418.718.118.116.115.214.513.111.1

7-Deo93 11.112.24.5

19-Jan-94 4.912.913.3

16-Feb-94 5.04.04.1

22122122

11200

111111221

112221222

222

122

020

33333554

33411

544544555

222222222

222

233

030

Sex: 1«Mate,2«Femate. Stage: 1* Inactive, 2^active, 3=Rtpe,4»Partial Spawn, 5=Spent, 0= Undefined (See Text)A 15

Station 4.1 Chipps Island

Date Length Sex Stage6-Mar-94

19-Apr-94

17-May-94

15-Jun-94

28-Jul-94

17.816.9

5.14.54.2

21.310.19.55.8

20.220.119.517.317.014.213.010.9

17.216.915.714.613.913.312.58.58.27.6

6.06.26.36.46.86.98.28.39.0

10.2

12020

2220

21111221

2222111111

2221110222

33030

3430

43344433

4445345445

1111111252

Date Length Sex Stage30-Aug-94

27-Sep-94

26-OCN94

29-Nov-94

4.16.76.78.99.5

10.218.918.1

20.920.720.216.212.912.811.910.79.4

8.511.112.312.913.013.514.819.820.220.3

11.711.811.913.114.114.514.715.217.521.1

00000012

211121112

2112212111

1121211221

00011122

222222222

2222222222

3323232333

Sex: 1«Mate,2«Female. Stage: 1« Inactive, 2=active, 3*RJpe, 4«Partial Spawn, S^Spent, 0=Undefined (See Text)A 16

Station 433 Honker Bay

Date Length Sex Stage6-Feb-91

11 -Mar-91

11 -Apr-91

5-Jun-91

14.714.211.119.211.813.113.611.78.9

13.9

10.816.511.19.6

11.19.78.0

10.47.28.9

8.88.5

10.78.3

10.110.19.6

14.110.810.0

9.29.17.9

10.910.212.111.913.613.7

2202012002

1212222212

0121212110

110122121

2212132102

3333231214

0555334440

330343434

Date Length Sex Stage11-Jul-91

1-Aug-91

12-Sep-91

1-Oct-91

11.28.2

11.18.5

12.79.4

12.08.8

13.58.1

8.08.2

11.711.211.310.013.810.512.111.5

7.88.4

13.09.5

10.08.88.1

12.112.2

18.87.88.0

11.210.87.87.0

10.08.1

10.0

1120212121

1221222122

112221112

1212120211

3550434333

4433333333

554555543

4545555555

Sex: 1-Mate, 2=Femate. Stage: 1« Inactive, 2=active, 3=Ripe, ^Partial Spawn, 5=Spent, 0=Undefined (See Text)A17

Station 433 Honker Bay

Date Length Sex Stage19-Nov-91

2-Feb-92

4-Mar-92

27-May-92

13.213.811.212.211.89.88.19.58.17.9

7.98.2

14.213.37.27.58.18.98.5

11.99.06.96.6

12.59.3

10.68.1

10.0

9.98.04.57.65.85.88.36.0

2210111200

112121122

212211112

11000000

5511155511

543544544

333354353

33000000

Date Length Sex Stage16-Jun-92

28-Jul-92

25-Aug-92

29-Sep-92

10.79.97.1

12.18.0

10.36.16.1

12.018.0

9.16.99.1

12.27.5

13.712.810.112.513.7

14.716.112.213.611.414.88.59.5

10.510.8

8.09.56.18.3

12.712.18.3

15.213.0

2211012011

1111122222

1011222211

111111021

4434555553

5433335343

3555353335

455554044

Sex: 1-Mate, 2-Femate. Stage: 1- Inactive, 2«active, 3«Ripe, 4»Partlal Spawn, 5=Spent, ^Undefined (See Text)

A 18

Station 433 Honker Bay

Date Length Sex Stage14-Oct-92

3-NOV-92

7-Dec-92

27-Jan-93

30-Mar-93

10.06.7

12.99.57.95.87.17.7

9.88.88.5

11.18.4

13.012.114.110.6

16.817.45.24.0

16.110.3

11.38.08,38.5

11.210.714.111.712.912.0

8.813.58.88.58.7

20001000

012022000

210011

1212211111

21221

41112111

122112111

331133

3343334434

53444

Date Length Sex Stage15-Apr-93

30-Jun-93

13-Jul-93

8-Sep-93

6-Oct-93

S-Nov-93

9.89.97.09.57.37.1

14.57.78.5

12.112.112.915.618.8

10.015.515.313.016.0

14.113.814.710.99.7

14.315.216.016.0

16.116.313.513.411.814.012.1

17.014.613.016.814.816.815.9

211122211

22211

11111

111112111

1221212

2211122

445344353

53333

43333

444344544

3555554

5454334

Sex: 1-Mate, 2-Femate Stage: 1« Inactive, 2«actlve, 3»Rlpe, 4«Partial Spawn, 5«Spent, 0*Undefined (See Text)

A 19

Station 433 Honker Bay

Date Length Sex Stage7-Dec-93

19- Jan-94

16-Feb-94

16-Mar-94

30-Aug-94

27-Sep-94

26-Oct-94

18.514.416.314.815.814.513.116.2

18.1

15.616.216.0

14.514.8

5.05.5

13.9

7.18.17.07.0

11.213.812.8

7.1

8.19.57.57.87.2

10.08.80.8

11.29.1

11212122

1

121

12

111

12212112

2121212221

33434345

3

333

33

444

54455545

5545454553

Date Length Sex Stage29-Nov-94

7-Dec-94

22.513.411.19.99.17.98.88.56.9

14.515.916.314.8

221222221

1221

545343455

3443

Sex: 1-Mate, 2=Femate. Stage: 1* Inactive, 2=8ctive, 3«Ripe, 4=Partial Spawn, 5=Spent, (^Undefined (See Text)

A 20

Station 12.5 San Pablo Bay

Date Length Sex Stage7-Jan-91 15.5

16.112.86.3

12.514.816.86.2

15.215.07.2

13.16.8

12.9

7-Feb-91 17.010.96.5

13.87.04.1

14.56.87.96.5

10.015.513.46.8

12-Mar-91 15.211.17.09.09.5

10.812.012.98.9

13.06.28.4

13.717.3

21221122121221

22220111111221

12112212112122

33434334334343

23221334233333

33333334343333

Date Length Sex Stage12-Apr-91

8-May-91

5-Jun-91

8.17.16.2

12.111.56.58.89.17.4

12.17.88.1

12.113.110.2

11.28.59.86.2

12.28.27.88.26.1

11.16.17.2

15.218.9

9.210.011.210.19.85.9

12.39.8

10.111.810.917.87.9

11.19.1

222212211222112

11212222212

212211112121

333333333334333

34454554554544

555455545555555

Sex: 1«Mate,2*Female. Stage: 1-Inactive, 2»active, 3=Ripe, 4= Partial Spawn, 5= Spent, 0=Urxtefined (Sec Text)A 21

Station 12.5 San Pablo Bay

Date Length Sex Stage11-Jul-91 6.9

8.08.18.09.3

13.012.912.812.212.116.116.514.318.115.5

2-Aug-91 10.513.17.8

10.014.513.39.5

11.712.013.811.314.114.8

12-Sep-91 8.07.97.08.9

10.011.512.011.913.710.114.014.411.516.316.6

102122122121121

1121211211221

021112221002112

555434345343453

5455445433343

545444444555444

Date Length Sex Stage1-Oct-91

19-Nov-91

IO-Dec-91

7-Jan-92

6.07.16.89.16.27.1

11.412.111.815.415.616.516.515.0

9.012.512.810.011.015.217.212.815.013.1

16.015.19.89.2

15.112.911.311.815.0

14.816.915.712.114.014.713.012.911.512.1

00200021211112

2121112122

221112122

2212

2

11511155555555

2223422552

222222222

3443343334

Sex: 1=Mate, 2-Femate. Stage: 1* Inactive, 2«acOve, 3»Rlpe, 4«Partial Spawn, 5*Spent, (^Undefined (See Text)

A22

Station 12.5 San Pablo Bay

Date Length Sex Stage5-Feb-92

4-Mar-92

8-Apr-92

28-May-92

10.811.910.012.39.8

12.610.19.7

10.1

11.010.211.110.711.310.114.513.612.3

12.59.5

10.28.38.47.09.58.89.08.2

10.812.810.58.1

10.811.711.010.611.98.8

222221121

212211121

1211221212

2121211221

433344444

433343333

4343333433

5544434443

Date Length Sex Stage28-Jul-92

22-Aug-92

14-Oct-92

22-Sep-92

13.311.214.812.814.712.913.710.99.5

12.1

10.813.511.114.314.814.79.6

15.210.911.8

13.214.515.815.514.913.011.013.410.5

9.0

13.516.115.011.512.311.512.212.112.1

2212122111

1122122121

1221221111

122222221

5555355555

3525355355

4333353335

543553545

Sex: 1-Mate, 2=Femate. Stage: 1« Inactive, 2*active, 3«Ripe, 4*Partial Spawn, 5=Spent, 0=Undefined (See Text)A 23

Station 12.5 San Pablo Bay

Date Length Sex Stage2-NOV-92

27-Jan-93

25-Feb-93

30-Mar-93

14.915.510.517.413.2

9.113.510.215.514.8

16.215.016.517.118.010.213.011.511.1

13.112.616.217.313.112.39.39.8

11.210.2

10.113.78.27.59.0

14.113.911.712.7

8.1

2211122222

212212121

1112122211

1221122121

5353345555

333343334

3333353333

3334333333

Date Length Sex Stage15-Apr-93

12-May-93

15-Jun-93

23-Jul-93

6.97.5

12.78.29.19.67.3

10.011.3

13.811.211.414.89.6

14.015.212.814.310.8

12.111.913.814.716.114.814.115.814.0

11.517.116.116.914.012.714.810.18.2

111211212

2121122121

222211111

111111212

333333433

4543544455

555544544

543444555

Sex: 1»Mate, 2»Femate. Stage: 1» Inactive, 2»acth/e,3«Ripel 4«Partial Spawn, 5*Spent, (^Undefined (See Text)

A 24

Station 12.5 San Pablo Bay

Date Length Sex Stage10-Aug-93

8-Sep-93

S-Oct-93

S-Nov-93

9.511.310.919.815.112.013.011.912.010.8

10.79.2

11.814.512.612.914.812.211.311.3

10.212.09.3

12.510.911.210.811.113.810.0

13.516.710.210.19.2

12.013.210.814.812.5

2211221121

0101021021

2221120001

2122211211

5555555555

1551125111

2232211111

2232232222

Date Length Sex Stage7-Dec-93

19- Jan-94

17-Mar-94

19-Apr-94

10.78.9

15.113.210.810.514.510.610.911.1

10.69.09.19.48.0

16.515.817.010.213.1

12.011.811.713.810.111.110.57.8

13.214.5

13.17.5

12.07.88.99.19.58.59.38.9

1121212211

2212222112

1122121112

2112111211

2122224242

3233332343

3333333333

4555555445

Sex: 1-Mate, 2«Femate. Stage: 1« Inactive, 2«active, 3«Ripe, 4*Partial Spawn, 5*Spent, 0*Undefined (See Text)A 25

Station 12.5 San Pablo Bay

Date Length Sex Stage17-May-94

28-Jul-94

30-Aug-94

27-Sep-94

10.08.9

10.611.69.01.1

11.211.310.511.4

11.511.311.013.512.010.812.113.312.513.2

9.08.8

12.011.313.110.210.511.712.512.2

12.011.513.812.812.310.210.814.814.9

0101021021

1121212221

1121221211

222102110

1212122125

2222223222

4444244334

333313531

Date Length Sex Stage26-Oct-94 9.9

9.710.49.2

11.010.712.111.212.213.7

Sex: 1»Mate,2»Female. Stage: 1= Inactive. 2»acUve,3=Ripe,4=Partial Spawn, 5=Spent,0*Undefined (See Text)

A 26