(DRAFT) - Taxonomy
Species abalone, green
Species Id M060012
Date 26 AUG 96
TAXONOMY
NAME - abalone, green
OTHER COMMON NAMES - green abalone
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - Gastropoda,
ORDER AND SUBORDER - Archaeogastropoda,
FAMILY AND SUBFAMILY - Haliotidae,
GENUS AND SUBGENUS - Haliotis,
SPECIES AND SSP - fulgens,
SCIENTIFIC NAME - Haliotis fulgens
AUTHORITY - Philippi
TAXONOMY REFERENCES - 64
Taxonomy - 1 (DRAFT) - Status
Species abalone, green
Species Id M060012
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
Commercial/consumption
REFERENCES FOR STATUS - 64
COMMENTS ON STATUS -
Green abalone are important in the commercial and sport fisheries of the
Pacific Southwest.*64*
The foot meat of the abalones is a highly prized delicacy, noted for its
rich flavor. The whole shell is used as an ornament, or broken into
smaller sections and polished for jewelry. Dwindling supplies have given
this prized mollusk the distinction of being the highest priced domestically
produced seafood in the United States.*64*
Status - 1 (DRAFT) - Distribution
Species abalone, green
Species Id M060012
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - MARINE
REFERENCES FOR HABITAT - 64
LAND USE -
Bays and Estuaries
REFERENCES FOR LAND USE - 64
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine RB.
Marine RB.
Marine RB2
Marine RB2
Marine, subtidal RB.
Marine, subtidal RB.
Marine, subtidal RB2
Marine, subtidal RB2
Marine, intertidal RB.
Marine, intertidal RB.
Marine, intertidal RB2
Marine, intertidal RB2
REFERENCES FOR NWI - 64
COMMENTS ON HABITAT ASSOCIATIONS -
Green abalone are most abundant along rock headlands from the low
intertidal zone to a subtidal depth of about 15 m. Headlands are exposed to
high wave and current turbulence and abalones there are concentrated in
crevices. The lower depth limits of abalones are governed by the severity
of the wave action, by the availability of drifting red algae for food, and
suitable water temperatures. Juveniles also are abundant in areas where
adults are abundant, especially in waters with strong currents and in
crevices where coralline algae thrive. Postlarvae settle gregariously among
adults. Most of the older juveniles and adult green abalone move frequently
in search of food and protection.*64*
Habitat Associations - 1 (DRAFT) - Food Habits
Species abalone, green
Species Id M060012
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
HERBIVORE/GRAZER
REFERENCES FOR TROPHIC LEVEL - 64
LIFESTAGE FOOD FOOD PART
Adult Algae Not Applicable
Larva Bacteria Not Applicable
Adult Chrysophyta Not Applicable
Adult See Comments; Food
Juvenile See Comments; Food
REFERENCES FOR ADULT FOOD - 64
REFERENCES FOR JUVENILE FOOD - 64
REFERENCES FOR LARVAE FOOD - 64
COMMENTS ON FOOD -
Abalones are herbivores that feed largely on brown and red algae, somewhat
in proportion to its availability. Densities are often high in locations
with abundant algal drift kelps.*64*
Newly hatched abalone have enough yolk to last for several days. By the
time the larva settles, its radula has developed sufficiently to enable the
ingestion of microalgae less than 10 micrometers long. Abalones less than
10 mm long usually subsist on a diet of sessile pennate diatoms. Small
abalones (less than 5 mm long) graze primarily on benthic microflora.
Although small juveniles do not feed directly on kelp, kelp beds provide
cryptic refuges that enhance survival of abalones. The young often grow
well in waters unsuitable for adults. Although small juveniles prefer to
feed on seaweeds with thin fronds, juveniles as short as 1 cm long can eat
the same food as adults. When kelp is sparse, diatoms may form a large
part of the adult diet.*64*
Coastal waters inhabited by abalones off California and Baja California
flourish with the Phaeophyta. The production of algae is highly seasonal
and the amount of algae being consumed usually reflects its availability.
In northern California waters in late fall, annuals begin to disintegrate
and perennials die back. The abundance of food then drops sharlply and
remains low until the following spring. At the same time, the growth of
the abalones drop sharply.*64*
Although bits of drift kelp are an important source of food, attached kelp
also is eaten.*64*
Green abalone eat brown algae proportionate to its abundance in the algal
drift. The larger brown algae Macrocystis and Egregia predominate in the
diet and produce the best growth. However, the green abalone strongly
prefers the red algae Gelidium, Pterocladia, Plocamium, and Gigartina. Red
Food Habits - 1 (DRAFT) - Food Habits
Species abalone, green
Species Id M060012
Date 26 AUG 96
algae are three times more abundant in the diet of the green abalone than
they are in the algal drift.*64*
COMMENTS ON ADULT FOOD -
Abalones are herbivores that feed largely on brown and red algae, somewhat
in proportion to its availability. Densities are often high in locations
with abundant algal drift kelps.*64*
Coastal waters inhabited by abalones off California and Baja California
flourish with the Phaeophyta. The production of algae is highly seasonal
and the amount of algae being consumed usually reflects its availability.
In northern California waters in late fall, annuals begin to disintegrate
and perennials die back. The abundance of food then drops sharlply and
remains low until the following spring. At the same time, the growth of
the abalones drop sharply.*64*
Although bits of drift kelp are an important source of food, attached kelp
also is eaten.*64*
Green abalone eat brown algae proportionate to its abundance in the algal
drift. The larger brown algae Macrocystis and Egregia predominate in the
diet and produce the best growth. However, the green abalone strongly
prefers the red algae Gelidium, Pterocladia, Plocamium, and Gigartina. Red
algae are three times more abundant in the diet of the green abalone than
they are in the algal drift.*64*
COMMENTS ON JUVENILE FOOD -
Abalones less than 10 mm long usually subsist on a diet of sessile pennate
diatoms. Small abalones (less than 5 mm long) graze primarily on benthic
microflora. Although small juveniles do not feed directly on kelp, kelp beds
provide cryptic refuges that enhance survival of abalones. The young often
grow well in waters unsuitable for adults. Although small juveniles prefer
to feed on seaweeds with thin fronds, juveniles as short as 1 cm long can
eat the same food as adults. When kelp is sparse, diatoms may form a large
part of the adult diet.*64*
COMMENTS ON LARVAE FOOD -
Newly hatched abalone have enough yolk to last for several days. By the
time the larva settles, its radula has developed sufficiently to enable the
ingestion of microalgae less than 10 micrometers long.*64*
Food Habits - 2 (DRAFT) - Environment Associations
Species abalone, green
Species Id M060012
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
E Water Temperature: Specified in Comments
L Water Temperature: Specified in Comments
FA Water Temperature: Specified in Comments
A Turbidity: Clear water
A Relation to Substrate: Attached - normally sessile
A Bottom Type [Aquatic]: Boulders
A Water Depth Preference: Specified in Comments
A Coastal Features: Rocky offshore islands
A Coastal Features: Rocky beaches
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 64
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
The thermal optima for the red abalone is between 14 and 18 degrees C.
The optimal temperature for egg fertilization is apparently 15 degrees C.
Red abalone eggs develop normally within a temperature range of 10-23
degrees C, but optimum larval growth is at 13.5-20 degrees C. At 18 degrees
C, larvae settle in about 5 days. Larval growth is temperature dependent;
only larvae reared between 14 and 18 degrees C reached the advanced
post-larval stages. The red abalone feeds at temperatures of 7 to 22
degrees C, but maximum feeding is between 13 and 18 degrees C. Growth was
fastest at temperatures between 15 and 20 degrees C and was only slightly
less at 12.5 degrees C.*64*
In northern California, red abalone inhabit water from 0 to 35 m deep, but
concentrate in water 1 to 6 m deep. In Morrow Bay, central California, the
red abalone lives in intertidal waters up to 30 m deep (maximum
concentrations are between 5 and 17 m), and as far as 2 miles offshore if
there is abundant rocky substrate and food supply. They are usually
Environment Associations - 1 (DRAFT) - Environment Associations
Species abalone, green
Species Id M060012
Date 26 AUG 96
restricted to rock bottoms 10 to 30 m deep. This depth distribution
correlates with an extended photic zone, generally higher algal production,
and more suitable temperatures at greater depths.*64*
In waters north of San Francisco, abalones occupy a narrow
coastal band, restricted to the nearshore waters where either drift or
attached kelp is available for food. Along the coasts of Sonoma and
Mendocino Counties in northern California, abalones are common below the
algal zone, especially along the bottoms of surge channels, and are not
always near attached algae. The availability of drift macroalgae varies
daily. Water movement is essential for transporting food that abalones can
catch. Abalones in deep water (20-30 m) live in channels serving as funnels
for drift kelp transported from shallow water. Along a coastline with
adjacent surge channels, abalones are characteristically further offshore.
This more seaward distribution is correlated with greater kelp abundance
there, either adrift or attached. Abalones are scarce where channels widen
and currents become diffuse.*64*
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
The thermal optima for the red abalone is between 14 and 18 degrees C.*64*
In northern California, red abalone inhabit water from 0 to 35 m deep, but
concentrate in water 1 to 6 m deep. In Morrow Bay, central California, the
red abalone lives in intertidal waters up to 30 m deep (maximum
concentrations are between 5 and 17 m), and as far as 2 miles offshore if
there is abundant rocky substrate and food supply. They are usually
restricted to rock bottoms 10 to 30 m deep. This depth distribution
correlates with an extended photic zone, generally higher algal production,
and more suitable temperatures at greater depths.*64*
In waters north of San Francisco, abalones occupy a narrow
coastal band, restricted to the nearshore waters where either drift or
attached kelp is available for food. Along the coasts of Sonoma and
Mendocino Counties in northern California, abalones are common below the
algal zone, especially along the bottoms of surge channels, and are not
always near attached algae. The availability of drift macroalgae varies
daily. Water movement is essential for transporting food that abalones can
catch. Abalones in deep water (20-30 m) live in channels serving as funnels
for drift kelp transported from shallow water. Along a coastline with
adjacent surge channels, abalones are characteristically further offshore.
This more seaward distribution is correlated with greater kelp abundance
there, either adrift or attached. Abalones are scarce where channels widen
and currents become diffuse.*64*
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
The red abalone feeds at temperatures of 7 to 22 degrees C, but maximum
feeding is between 13 and 18 degrees C. Growth was fastest at temperatures
between 15 and 20 degrees C and was only slightly less at 12.5 degrees
C.*64*
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
Red abalone eggs develop normally within a temperature range of 10-23
degrees C, but optimum larval growth is at 13.5-20 degrees C. At 18 degrees
Environment Associations - 2 (DRAFT) - Environment Associations
Species abalone, green
Species Id M060012
Date 26 AUG 96
C, larvae settle in about 5 days. Larval growth is temperature dependent;
only larvae reared between 14 and 18 degrees C reached the advanced
post-larval stages.*64*
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
The optimal temperature for egg fertilization is 15 degrees C.*64*
Environment Associations - 3 (DRAFT) - Life History
Species abalone, green
Species Id M060012
Date 26 AUG 96
LIFE HISTORY
MORPHOLOGY: The shell of the green abalone is oval; its average length is
175 mm (maximum 250 mm). The shell exterior is olive-green to red-brown and
regular in form and sculpture with fine spiral ribs. The shell surface is
often overgrown with encrusting invertebrates and algae. The circular
respiratory apertures are about 5 mm in diameter and slightly raised;
usually five to seven are open. The shell interior is smooth and strongly
iridescent, having deep green, blue, and lavender shades and some black
spots. A prominent, central, columellar muscle scar is present; the shell
is considered to be the most beautiful of all abalones.*64*
The epipodium of the green abalone is olive green with patches of brown. It
is scalloped along the edge and small tuberculations give it a rough,
frilled surface. Epipodial tentacles are grayish green, short, and thick,
and project slightly.*64*
REPRODUCTION: Abalones lack evident sexual dimorphism and are dioecious,
broadcast spawners. The sex of mature specimens can be determined by
gonadal color. The testis is usually white, yellow-cream, or beige. The
green abalone has brownish-green ovarian tissue and produces brown eggs.
Immature gonads are brown or brownish-gray--the color of the hepatic
tissue.*64*
Maturation of the gonads depends largely on the quality and quantity of
available food, and to a lesser extent on temperature (within certain
limits). Seasonal changes in the availability of food may determine the
period of gamete production. Low food intake, combined with seasonally low
ambient water temperatures, may cause suboptimal gamete development. Green
abalones spawn primarily in the spring and early summer.*64*
Green abalone spawn from April through October in California coastal waters
and as far south as Ensenada and Cedros Island in Mexico. Green abalone off
Santa Catalina Island may spawn twice a year. They mature sexually at 5 to
7 years of age at lengths of 80 to 120 mm. In laboratory experiments, green
abalone became sexually mature and produced viable larvae as early as 1.5
years and lengths of 40 to 50 mm. In California coastal waters, individual
green abalone may produce from 100,000 to 6 million eggs per spawn.*64*
BEHAVIOR: Abalones feed by raising their shell and extending their
epipodium. When a piece of drift touches the epipodium, the abalone turns
toward the food and grasps it with the highly prehensile anterior lobes of
the foot. By creating rhythmical contractions of the foot the algae is
drawn under the anterior half of the foot. Water current, light, and other
stimuli also elicit feeding behavior.*64*
POPULATION ATTRIBUTES: Larval development of the abalones is
well-documented. Because the specific gravity of spawned eggs is greater
than that of sea water, the eggs sink to the bottom. Upon fertilization, a
membrane forms and larval development begins. The rate of embryonic
development depends on temperature. Trochophore larvae hatch in 10 to 72
hours when the eggs are reared at water temperatures of 12 to 20 degrees C.
Larvae are lecithotrophic. Trochophores and veligers are most abundant near
Life History - 1 (DRAFT) - Life History
Species abalone, green
Species Id M060012
Date 26 AUG 96
the surface of the water.*64*
Pigmentation of velar and visceral portions of the larvae may provide
distinctive features for recognition of some species. Pigments derived from
parental yolk appear to be retained by trochophore and veliger larvae of
Haliotis. In the laboratory, veligers settle on the substrate when they are
5 to 14 days old. Settling of postlarvae on coralline red algae can be
induced by substances released in the water by the algae. Metamorphosis
into juveniles requires individual contact with red algae, yet there is some
evidence that settling is a random phenomenon. Settlement (the crawling
stage) marks the end of larval life.*64*
Postlarvae are the settled young up to 10 mm long. They are characterized
by the loss of the velar cilia and operculum, and the pronounced development
of the foot and shell. After 2 weeks, the postlarvae leave the coralline
alga on which they have settled and attach to rocks, especially in crevices.
The postlarvae have a well-developed radula (rasping tooth structure) for
feeding on bacteria and diatoms that grow as a film on the substrate. Once
they have started to feed, they begin to deposit the peristomal shell
around the lip of the larval shell aperture. The shell is depressed and
grows in the form of an equiangular spiral. New shell material is
deposited to a greater extent on the right side of the aperture, producing
a shell with a right-handed whorl. The spiral becomes flattened and the shell becomes
ear-shaped, a form well suited for clinging.*64*
Sensory tentacles have two ciliary lobes that create water currents over the
ctenidia and epipodial tentacles, which function as chemo-sensory and
tactile-sensory structures. When postlarvae are 1 to 3 months old and the
shell is about 2 mm long, the first respiratory pore forms as the mantle
separates along the sinistral margin of the shell opening and creates a
notch. As growth proceeds, old pores are closed and new ones are formed one
at a time along the growing margin of the shell. When the abalone is about
10 mm long--now a juvenile--it begins feeding largely on macroalgae, and to
a much lesser extent on microflora. Abalones are seldom seen in the open
until they are 75 to 100 mm long.*64*
The length of most abalone is 1 to 3 mm at the end of 3 months, about 20 mm
at the end of the first year of life, and 75 to 100 mm by the end of the
third to fourth year. Growth in girth and weight increase as length
increases.*64*
In laboratory experiments, green abalone were as long as 30 mm by the end of
their first year of life.*64*
Growth rates of abalones fluctuate with the seasonal abundance of kelps.
Growth is rapid during the summer, when brown macroalgae are most abundant.
Differences in growth rates also may reflect the differential nutrient
quality of the available algae. In winter along the north coast of
California, abalones may lose weight because of the paucity of brown algae
for food.*64*
According to researchers, the rate of shell growth slows or stops during
periods of accelerated gonadal growth, but more recent studies in the
Life History - 2 (DRAFT) - Life History
Species abalone, green
Species Id M060012
Date 26 AUG 96
laboratory indicate that shell growth and gonadal maturation may be
simultaneous. Gonadal development is fastest when the diet consists of
giant kelp.*64*
Only a small percentage of abalones grow fast. Under optimal conditions in
a laboratory culture, some juvenile green abalone grow as much as 50 mm in
one year; however, the average is near 25 mm in the sea.*64*
LIFE HISTORY CODES -
Average Number of Offspring/Reproductive Effort: Grea
Foraging Strategy: Grazing
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Display Site: Water
Periodicity: Most active in early summer
Periodicity: Most active in late summer
REFERENCES FOR LIFE HISTORY- 64
Life History - 3 (DRAFT) - Management Practices
Species abalone, green
Species Id M060012
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Prohibiting harvest of species being described
Beneficial Regulating harvest - restricting weapons/gear use
Beneficial Regulating harvest - restricting number of hunters
Beneficial Regulating harvest - setting bag/creel limits
Beneficial Regulating harvest - setting size limits
Beneficial Other management practices [specified in comments]
Adverse Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 64
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 64
COMMENTS ON MANAGEMENT PRACTICES -
Commercial fishing for abalones is banned north of San Francisco.*64*
The commercial fishery in southern California is regulated by a split season
(closures during February and August) and by size limits. Fishing is
regulated by limited entry. Commercial divers are restricted by types of
gear, diving depth, and area boundaries.*64*
The daily possession limit in California is four abalones of any
combination of species. Eight abalones are allowed in possession by
sport-divers declaring a multi-day trip to offshore waters.*64*
Sea otters have depleted the most productive abalone grounds and are a
threat to all abalone populations in California. Although the Marine Mammal
Protection Act of 1972 categorizes the sea otter as a threatened species,
many authorities in California believe that it must be contained within a
restricted range as a necessary prerequisite to the development of a viable
management plan for abalone resources in California.*64*
Studies are being conducted to determine the feasibility of rearing 1- to
2-year-old abalones of several species in the laboratory and transplanting
them into suitable habitats where populations have declined. Seeding
abalone habitat with juveniles may prove to be an effective means of
repopulating formerly productive waters.*64*
Management Practices - 1 (DRAFT) - References
Species abalone, green
Species Id M060012
Date 26 AUG 96
References
*64* Ault, J.S. 1985. Species Profiles: Life Histories and
Environmental Requirements of Coastal Fishes and Invertebrates
(Pacific Southwest) -- Black, Green, and Red Abalones. U.S. Fish
and Wildlife Service Biol. Rep. 82(11.32) pp 19.
References - 1