(DRAFT) - Taxonomy
Species abalone, red
Species Id M060013
Date 26 AUG 96
TAXONOMY
NAME - abalone, red
OTHER COMMON NAMES - red 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 - rufescens,
SCIENTIFIC NAME - Haliotis rufescens
AUTHORITY - Swainson
TAXONOMY REFERENCES - 64
Taxonomy - 1 (DRAFT) - Status
Species abalone, red
Species Id M060013
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
Commercial/consumption
REFERENCES FOR STATUS - 64
COMMENTS ON STATUS -
Red abalone are important in the commercial and sport fisheries of the
Pacific Southwest. Historically, most of the commercial catch consisted
of red abalone taken from central California coastal waters between Cape San
Martin (Monterey County) and Avila (San Luis Obispo County); however,
commerical landings of red abalone in central California have declined
partly because of the expansion of the range of the highly predatory sea
otter into old established abalone grounds.*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, red
Species Id M060013
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 RB1
Marine RB1
Marine RB2
Marine RB2
Marine, subtidal RB.
Marine, subtidal RB.
Marine, subtidal RB1
Marine, subtidal RB1
Marine, subtidal RB2
Marine, subtidal RB2
Marine, intertidal RB.
Marine, intertidal RB.
Marine, intertidal RB1
Marine, intertidal RB1
Marine, intertidal RB2
Marine, intertidal RB2
REFERENCES FOR NWI - 64
COMMENTS ON HABITAT ASSOCIATIONS -
In northern California, red abalone live in the lower intertidal zone, to a
depth of about 6 m. In southern California they live subtidally out to
depths of 40 m but in northern California abalones longer than 75 mm live
in crevices, under large boulders, and on exposed bedrock where sea otters
are scarce. Smaller red abalone are cryptic, at least diurnally. Red
abalone up to 20 mm long commonly live under clean boulders with veneers of
inarticulate coralline algae. Red abalone upto 80 mm long commonly live in
crevices. The seams, cutbacks and ledges in rock faces where algae are
abundant provide optimal habitat for red abalone. Red abalone seek
locations where food is abundant and relatively easy to capture. the
largest specimens tend to live in the choice locations. Some abalone are
relatively inactive and do not forage unless they are unable to catch
sufficient drift algae; they then forage mostly among kelp stnads.*64*
Habitat Associations - 1 (DRAFT) - Food Habits
Species abalone, red
Species Id M060013
Date 26 AUG 96
FOOD HABITS
Food Habits - 1 (DRAFT) - Environment Associations
Species abalone, red
Species Id M060013
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
L Water Temperature: Specified in Comments
J Water Temperature: Specified in Comments
LIM Water Temperature: Specified in Comments
A Turbidity: Clear water
A Relation to Substrate: Attached - normally sessile
A Bottom Type [Aquatic]: Boulders
A Bottom Type [Aquatic]: Bedrock
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 JUVENILE ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 64
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 64
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Larval and juvenile green abalone grow and survive well at 20 to 28 degrees
C, but the optimum temperature is between 18 and 24 degrees C. The time
required for green abalone larvae to reach the settling stage varies from
3.5 days at 24 degrees C to 12 days at 14 degrees C. Larvae incubated at
12 degrees C failed to settle within 2 weeks. Young laboratory-reared
green abalone grew fastest at temperatures of 22 to 28 degrees C. When
postlarvae were reared at near optimal thermal and feeding conditions, they
formed the respiratory pore in about half the time required by other
California abalones. The "notch stage" was reached in some rapid-growing
green abalones within 30 days after fertilization. Juveniles usually live
beneath rocks and in crevices in the lower intertidal zone where they are
exposed to temperatures of about 12 to 26 degrees C. In one experiment,
the growth rates of juveniles in thermal effluent (22-28 degrees C) were
increased twofold over those reared at ambient temperatures (14-20 degrees
C). Increases in shell growth are linearly dependent on temperature.
Environment Associations - 1 (DRAFT) - Environment Associations
Species abalone, red
Species Id M060013
Date 26 AUG 96
Green abalones grow fastest in water at about 26 degrees C. The optimal
thermal range for somatic growth declines with age, corresponding with the
lower temperatures in the sublittoral areas occupied by adults.*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_ -
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 JUVENILE ENVIRONMENTAL ASSOC_ -
Larval and juvenile green abalone grow and survive well at 20 to 28 degrees
C, but the optimum temperature is between 18 and 24 degrees C.*64*
Juveniles usually live beneath rocks and in crevices in the lower
intertidal zone where they are exposed to temperatures of about 12 to 26
degrees C. In one experiment, the growth rates of juveniles in thermal
effluent (22-28 degrees C) were increased twofold over those reared at
ambient temperatures (14-20 degrees C).*64*
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
Larval and juvenile green abalone grow and survive well at 20 to 28 degrees
C, but the optimum temperature is between 18 and 24 degrees C. The time
required for green abalone larvae to reach the settling stage varies from
3.5 days at 24 degrees C to 12 days at 14 degrees C. Larvae incubated at
12 degrees C failed to settle within 2 weeks. Young laboratory-reared
green abalone grew fastest at temperatures of 22 to 28 degrees C. When
postlarvae were reared at near optimal thermal and feeding conditions, they
formed the respiratory pore in about half the time required by other
California abalones.*64*
Environment Associations - 2 (DRAFT) - Life History
Species abalone, red
Species Id M060013
Date 26 AUG 96
LIFE HISTORY
MORPHOLOGY: The red abalone is the largest of the abalones. The average
shell length is about 220 mm (maximum 292 mm). Usually, three to four
respiratory pores are open along the sinistral margin of the shell at a
given time. The outline of the pores are oval and typically slightly
elevated. The shell exterior is commonly lumpy, irregular, and red. The
redness is conferred by red algae in the diet. The ostracal shell layer is
typically dull brick red. If red abalone feed on brown rather than red
algae, the shell colors range from white to cream to green, depending on the
particular brown algae being consumed. The shell is often overgrown by
sessile organisms that are common to the area. The shell interior is smooth
and brilliantly iridescent with deep green and blue shades; green and black
spots may also be present. The intercolumellar muscle scar with rough
texture. The outer lip of the shell extends over an inner nacreous surface
forming a rim (red if the abalone has been feeding on red algae).*64*
The epipodium and lateral portion of the foot are smooth and usually black;
however, the epipodium of a second prominent phenotype has alternating dark
and light vertical bars. The edge of the epipodium is scalloped; black
epipodial tentacles can be extended beyond the edge of the shell. In some
individuals, the upper edge of the epipodium is white. The epipodium
protrudes beyond the edge of the shell when the animal is either relaxed or
feeding.*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
ovarian tissue is dark green in red abalones and their larvae are
conspicuously green.*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. Red
abalones spawn primarily in the spring and early summer.*64*
Peak spawning of red abalone in the northern portion of their range
coincides with spring benthic brown algal blooms. In northern California,
the spawning season extends from April through July. In southern
California, they may spawn twice annually. Abalone living in the same
environments have relatively uniform and similar gonadal development. Most
red abalone in northern California become sexually mature when shell length
is about 100 mm. Abalone spawning for the first time may produce only a few thousnad eggs, but older females may yield up to 6 million
eggs. Red abalone reared in the laboratory became sexually mature and
yielded viable larvae when about 40 mm long. Under optimum laboratory
conditions, the fecundity of individual abalone can be doubled.
Gametogenesis of coastal red abalone is begun immediately after spawning and
may be completed within 4 months. Female red abalone first spawn in their
third or fourth year of life and may continue to spawn for as long as 10
years. Necrosis of ova is suspected in geriatric females. Insufficient
nutrition inhibits egg production and in extreme cases the eggs may be
Life History - 1 (DRAFT) - Life History
Species abalone, red
Species Id M060013
Date 26 AUG 96
resorbed.*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
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
Life History - 2 (DRAFT) - Life History
Species abalone, red
Species Id M060013
Date 26 AUG 96
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. The maximum length for red abalone is about 290 mm.*64*
Tagged juvenile red abalone grew up to 48 mm in 1 year in central
California.*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
qualtiy 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. In northern California, about 80% of the annual growth of red
abalone is during peak algal production in summer and fall.*64
According to researchers, the rate of shell growth slows or stops during
periods of accelerated gonadal growth, but more recent studies in the
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 red abalone grow as much as 50 mm in
one year; however, the average is near 25 mm in the sea.*64*
LIFE HISTORY CODES -
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, red
Species Id M060013
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, red
Species Id M060013
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