(DRAFT) - Taxonomy
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
TAXONOMY
NAME - oyster, Olympia
OTHER COMMON NAMES - California oyster, native oyster, shoalwater oyster, Yaquina Bay oyster and rock oyster
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - Bivalvia,
ORDER AND SUBORDER - Pteroidea,
FAMILY AND SUBFAMILY - Ostreidae,
GENUS AND SUBGENUS - Ostrea,
SPECIES AND SSP - lurida,
SCIENTIFIC NAME - Ostrea lurida
AUTHORITY -
TAXONOMY REFERENCES - 238
COMMENTS ON TAXONOMY -
Other common names include California oyster, native oyster, shoalwater
oyster, Yaquina Bay oyster, rock oyster.*238*
Taxonomy - 1 (DRAFT) - Status
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
Commercial/consumption
Subsistence
REFERENCES FOR STATUS - 238
COMMENTS ON STATUS -
The Olympia oyster once supported an Indian sustenance fishery and a
commercial fishery, and was used to establish a maricultural industry on the
west coast of the United States. Examination of Indian kitchen middens near
San Francisco Bay revealed Olympia oyster shells in sufficient quantities to
establish the animals as an important food item of coastal tribes.*238*
Olympia oysters still form a reef and have repopulated much of Humboldt Bay,
allowing a sport harvest.*238*
Status - 1 (DRAFT) - Distribution
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - MARINE
REFERENCES FOR HABITAT - 238
LAND USE -
Bays and Estuaries
REFERENCES FOR LAND USE - 238
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine RF2 L
Marine, subtidal RF2 L
Marine, intertidal RF2 L
REFERENCES FOR NWI - 238
COMMENTS ON HABITAT ASSOCIATIONS -
Olympia oysters survive in a broad range of habitats but are most abundant
in estuaries, small rivers and streams.*238*
Olympia oyster reefs are formed in the subtidal zone and are bordered by
mud flats at high elevations and by eel grass beds at low elevations. They
are found at depths of 0 to 71 m. Oysters may attach to the underside of
rocks higher in the intertidal zone where the bottom is gravel or
rock.*238*
Habitat Associations - 1 (DRAFT) - Food Habits
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
FILTERER
REFERENCES FOR TROPHIC LEVEL - 238
LIFESTAGE FOOD FOOD PART
General Phytoplankton Not Applicable
REFERENCES FOR GENERAL FOOD - 238
COMMENTS ON FOOD -
Olympia oysters are filter feeders and rely on phytoplankton in the tidal
waters as a food source. The ostia--gill openings through which water
passes--are larger in the Olympia oyster than in the Japanese oyster. The
large ostia result in the selection of larger food items and do not allow
the Olympia oyster to consume nannoplankton.*238*
Food Habits - 1 (DRAFT) - Environment Associations
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G
G Relation to Substrate: Attached - normally sessile
G Bottom Type [Aquatic]: Boulders
G Bottom Type [Aquatic]: Specified in Comments
G Water Depth Preference: Specified in Comments
G Coastal Features: Reefs
G Coastal Features: Rocky beaches
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 238
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Olympia oysters are sensitive to extreme high or low temperatures. Average
water temperatures for southern Puget Sound are 6 to 9 degrees C in winter
and 18 to 20 degrees C in summer. In Olympia oysters held at Milford,
Connecticut, through the winter, mortalities were 100% at -1.0 to 5.0
degrees C and 3% at 12.0 to 13.0 degrees C.*238*
Olympic oysters thrive at salinities above 25 ppt but tolerate occasional
short exposure to lower salinities. Some oyster growers overcome predation
from flatworms and drills by using oyster grounds which have flows of
freshwater at low tide. The Olympia oysters can survive the salinity change
but the flatworms and eggs of the drill cannot.*238*
Environment Associations - 1 (DRAFT) - Life History
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
LIFE HISTORY
MORPHOLOGY:
The lower (left) valve is shallowly concave and the upper (right) valve fits
into the raised margin of the opposite valve. Shell shape is extremely
variable. Shells on substrate will conform to the shape of the substrate.
The shells of free-growing oysters are ovate to elongate. The exterior of
the shell is without a periostracum, varies from white to purplish black,
and may be striped with yellow or purplish brown. The interior of the
valves is white to olive green and the scar of the adductor muscle is not
much darker than the rest of the shell's interior.*238*
REPRODUCTION:
The life history of the Olympia oyster is similar to that of other oysters
of the genus Ostrea. The oyster initially spawns as a male then alternates
its functional gender between each spawning cycle.*238*
Spawning begins at water temperatures of 13 to 16 degrees C. In the southern
portion of the oysters' range, spawning occurs from spring to fall, peaking
in spring and to a lesser extent in fall. In the central part of its range,
spawning may be a prolonged period or may consist of one or two spawning
periods in mid-summer. In the northern portion, there may be only one or
two spawning periods in mid-summer.*238*
Spawning begins when males release clusters of sperm into the mantle
cavity. These sperm balls, which are expelled from the body by contractions
of the shell, disintegrate in seawater and release the spermatozoa.
Spermatozoa are brought into the mantle cavity of the female with water
pumped by the gills and the eggs are fertilized. Presence of spermatozoa in
seawater will stimulate synchronous spawning in Olympia oysters. The
fertilized eggs develop into veliger larvae in the oyster's mantle chamber
before they are discharged 10 to 12 days later. An average brood of larvae
is 250,000 to 300,000. At discharge, the larvae are 185 to 187 micrometers
long. The veliger stage lasts 11 to 16 days.*238*
SPECIES ORIGIN WITHIN STATE:
This species was introduced from Japan.*238*
LIMITING FACTORS:
Several introduced predators and parasites attack Olympia oysters. Two
introduced invertebrate predators of Olympia oysters are the Japanese oyster
drill Ocenebrajaponica and the flatworm Pseudostylochus ostreophagus. These
two species were introduced with regualr sea shipments of Pacific oyster
spat from Japan. The copepod Mytilicola orientalis ("red worm") lives in
the anus of oysters, and oysters infected by it are usually in poor
condition; this species was also introduced from Japan. In southern Puget
Sound, the slipper shell Crepidula fornicata may compete with Olympia
oysters for food and space and is a major fouling organism on the oyster's
shell. This slipper shell was introduced from the East Coast with the
shipment of American oysters. Other pests are the ghost shrimp and the blue
mud shrimp. The burrowing activity of these shrimp stirs up sediment and
also weakens the dykes used for culturing oysters.*238*
Olympia oysters have several natural predators. Some sea ducks (scaups and
scoters) feed on Olympia oysters, and the rock crab Cancer productus is an
important predator over much of the oyster's range. In California, the bat
ray Myliobatis californica is an oyster predator. In Yaquina Bay, Oregon,
histological examination of Olympia oysters has revealed a proliferative
cellular disorder characterized by large, apparently abnormal cells that
Life History - 1 (DRAFT) - Life History
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
proliferate rapidly and cause death. the etiology of this disease is
unknown. Tissue examination of oysters from Puget Sound, Washington,
collected after cold-water mortality showed the presence of Hexamita and
bacteria. Experimentation showed that Hexamita, a flagellated protozoan,
could be transmitted to healthy oysters and act as a pathogen at low
temperatures.*238*
POPULATION ATTRIBUTES:
The larvae develop an eyespot and foot and begin to crawl on hard substrate
then metamorphose into spat. The preferred substrate is old oyster shells,
but rocks, wood, metal, or any other hard material may be used as a setting
surface. Olympia oyster spat is often set on the underside of horizontal
surfaces. This is not a phototrophic response, but is attributed to the
swimming position of the larvae in which the foot is held in a superior
position. The oyster crawls with the foot on the surface and glue is
secreted from the byssus gland, which attaches the shell to the
substrate.*238*
Artificial spat collectors that create a turbulent waterflow, disrupting the
normal swimming position of larvae, collect spat on the upper and underside
of horizontal surfaces. Artificial spat collectors, used to collect spat
commercially, may be boards, pipes, or cardboard egg divdiders covered with
a slurry of hydrated lime, portland cement, and fine sand. Olympia oysters
differ from other species in that the substrate on which they settle need
not be particularly clean and may be placed in the water in advance of spat
settlement.*238*
The Olypmia oyster grows slowly, reaching shell heights of 35 to 45 mm in
three years in Washington State and has little or no growth thereafter.
Shell height increased 2 mm per week at the Scripps Institute of
Oceanography in southern California. Growth slows as the oysters mature
but shell heights of 50 mm are sometimes reached in 30 weeks. The maximum
reported size of Olympia oysters is 75 mm.*238*
The maximum age of Olympia oysters has not been reported. In adults held in
long-term bioassays, annual mortality was 34% in control groups.*238*
LIFE HISTORY CODES -
Foraging Strategy: Filtering
Display Site: Water
Spawning Site: Rocks
Gestation/Incubation Period: 3-4 weeks
Average Number of Offspring/Reproductive Effort: Grea
Number of Broods/Litters (Reproductive Efforts) Per Ye
Number of Broods/Litters (Reproductive Efforts) Per Ye
REFERENCES FOR LIFE HISTORY- 238
Life History - 2 (DRAFT) - Management Practices
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Put-and-take stocking
Beneficial Placing artificial reefs under water
Beneficial Constructing/maintaining bulkheads, seawalls, and dikes
Adverse Other management practices [specified in comments]
Adverse Other management practices [specified in comments]
Adverse Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 238
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 238
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 238
COMMENTS ON MANAGEMENT PRACTICES -
Early husbandry of the oysters was practiced by returning oyster shells to
oyster reefs which provided substrate for new generations of oysters. In
the early 1900's, the construction of dyked oyster beds, which held water at
low tide and had gravel bottoms, marked a major development in oyster
culture. Oyster shells were placed in locations favored for spat
collection. Cultch containing Olympia oysters was spread in the dyked beds
and left for 3.5 to 5 years until most of the oysters had reached a
marketable size or 35-40 mm. These oysters were marketed as shucked meats
rather than in the shell.*238*
The decline in cultured Olympia oyster production was attributed to
urbanization and domestic pollution and industrial pollution. The discharge
of sulphite waste liquor from pulp mills has been especially destructive to
oysters. Major growing grounds previously used for Olympia oysters are used
to grow Pacific oysters thus further reducing production of Olympia
oysters.*238*
The assemblage of invertebrates in bays of the Pacific coast is currently
cosmopolitan, owing to the introduction of exotic species. Possibly some
displacement of native species by invading exotic species has occurred.*238*
Silt from highway construction has caused high mortality by smothering
oysters in shallow areas of southern Puget Sound. Olympia oyster
populations have never recovered to their preexploitation levels.*238*
Management Practices - 1 (DRAFT) - References
Species oyster, Olympia
Species Id M060200
Date 26 AUG 96
References
238 * Couch, David, T.H. Hassler. 1989. Species Profiles and
Environmental Requirements of Coastal Fishes and Invertebrates
(Pacific Northwest) --Olympia oyster. Species Profile Series
82(11.124) (ed.). U.S. Fish and Wildlife Service Washington,
DC:8.
References - 1