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Haliotis fulgens

By Joshua Williams and Sarah Yesil

Geographic Range

Distribution of the green abalone, Haliotis fulgens, in the Pacific Ocean ranges from Point Conception in Santa Barbara, California to the mid-coast of Baja California, Mexico. (MacGinitie and MacGinitie, 1949)

Habitat

The green abalone resides in shallow water, in depths from nine meters to eighteen meters. The abalone is found in rock crevices, and other protected cavities in the inter-tidal zones. (Buchsbaum and Milne, 1960)

  • Range depth
    9 to 18 m
    29.53 to 59.06 ft

Physical Description

The green abalone has a flattened univalve shell scored with wavy lines; five to seven raised holes lie along the shell margin. These holes are used for excurrent water flow in the process of respiration. Its shell length approaches 13 cm, and ranges in color from dark shades of maroon to brown. The inside of the shell is coated with nacre of a lustrous blue-green color. A ruffle of tissue (called the epipodium) lines the edge of the wide, muscular foot which the animal uses to crawl over hard substrata. The foot is cream and brown in color, with tubercles along the edges. (Handorf, 2000; Neuman, 2009)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    13 (high) cm
    5.12 (high) in

Development

Haliotis fulgens passes through several life stages. First the egg is fertilized, and hatches after 20 to 30 days. The egg hatches into a trochophore larva, a free-swimming, ciliated planktonic stage. This develops into the next stage, a free-swimming veliger larva. The veliger eventually sinks to the ocean floor, and becomes a sedentary juvenile. Eventually, juveniles develop into reproductive adults. ("Abalone: Reproduction and Growth", 2003)

Reproduction

The green abalone reproduces by broadcast spawning, when both sexes release their gametes into the water. ("Abalone: Reproduction and Growth", 2003)

The sex of the abalone can be determined by gonad color. The gonads are creamy white in males, and green in females. During broadcast spawning, abalones release thousands of sperm and eggs into the water column; thus, fertilization is external. There is no seasonal reproductive cycle, however. Abalone release sperm or egg into the water when they sense chemicals released during spawning by conspecifics. Spawning all at once increases the odds of fertilization. Green abalone reach sexual maturity in 2 to 4 years. ("Abalone: Reproduction and Growth", 2003)

  • Breeding interval
    Abalone breed frequently throughout the year. They release sperm or egg into the water column if they sense others have done so.
  • Breeding season
    Breeding takes place year round.
  • Range number of offspring
    10,000 to 11,000,000
  • Average number of offspring
    5,505,000
  • Range gestation period
    20 to 30 hours
  • Average time to independence
    0 minutes
  • Range age at sexual or reproductive maturity (female)
    2 to 4 years
  • Range age at sexual or reproductive maturity (male)
    2 to 4 years

There is no parental investment, as this species is a broadcast spawner. Halitosis fulgens releases its gametes, and the offspring are independent right from fertilization on. ("Abalone: Reproduction and Growth", 2003)

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Lifespan in the wild is estimated at 30 or more years. Mortality rate of young abalone is high because of predation. Lifespan is also limited by the amount of available food. Since the abalone’s diet mainly consists of drifting algae, its lifespan is directly related to the persistence of kelp forests. Due to destruction of the kelp beds via human activities and natural events, lifespan of Haliotis fulgens can be affected greatly. ("Abalone Growth and Development", 1996; Neuman, 2009; Sheets, 1974)

  • Average lifespan
    Status: wild
    30 years

Behavior

Haliotis fulgens is a nocturnal, solitary creature that lives under rocks and in crevices in shallow areas. It only moves around if algae is scarce; otherwise it is a sedentary, sessile creature. It moves by crawling forward with its foot. ("Abalone Growth and Development", 1996; Neuman, 2009)

Home Range

Depending on food availability, abalone may stay in the same general area for months. Abalone are known to compete with sea urchins for crevices in rocky substrates, but they do not formally defend a territory. ("Abalone Growth and Development", 1996; Neuman, 2009)

Communication and Perception

Haliotis fulgens uses its ruffled epipodium and tentacles along the inside of the foot to sense its environment. Green abalones have a pair of eyes that detect light and shadow. Individuals have olfactory senses to detect chemicals released by conspecifics that induce spawning. The sperm and eggs of green abalone communicate (in a way) through chemicals. Dissolved signal molecules cause sperm to accelerate towards an egg. Through the use of nuclear magnetic resonance spectroscopy, the sperm attractant was found to be the amino acid L-trytophan. (Gruenthal, 2007; Neuman, 2009; Riffell, et al., 2002)

Food Habits

The diet of the green abalone mainly consists of drift and attached seaweed. Species composition of the diet is directly related to the species abundance of algae in the environment. The green abalone prefers fleshy red algae, and when food is scarce, it is forced to forage. Like all gastropods, abalone use their toothed radula to scrape and ingest their food. (Anderson, 2003; Perez-Estrada, et al., 2011)

Predation

The abalone is prey to any creature that can dislodge it from its rock. Predators include seals (Phoca vitulina), sea lions (Zalophus californiaus), sea otters (Enhydra lutris), fish, octopus (Octopus bimaculoides), and sea stars (Asteroidea). Humans are another threat to abalone as well.

The abalone's greatest natural predator is the sunflower star (Pycnopodia helianthoides). The sunflower star has no problem with the shell as it simply engulfs the entire abalone and digests it. The only anti-predator defense that Haliotis fulgens has is by clamping down onto its rock or by crawling away from its predator. ("Predators & Defenses", 2007)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Haliotis fulgens has a large role in the coastal ecosystem; as a herbivorous grazer it affects algal recruitment onto bare surfaces via its radular scraping while feeding. As a juvenile, the green abalone is easy prey for secondary consumers. The young seek refuge among rocks and under the spine canopy of the red sea urchin Strongylocentrotus franciscanus. The sea urchins protect the abalone from predators in a commensal relationship. In many cases, areas with low counts of sea urchins also show low counts of abalone. However, as the abalone grow and reach adult size, they no longer need protection from sea urchins, and competition for space begins, as both creatures prefer to inhabit the same microhabitat of rock crevices. ("Predators & Defenses", 2007)

The abalone's shell provides a hard substrate for epifaunal organisms to colonize, including various benthic invertebrates such as worm snails, sponges, date mussels, and bryozoans. ("Abalone: Reproduction and Growth", 2003)

  • Ecosystem Impact
  • creates habitat
Species Used as Host
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Haliotis fulgens has economic importance to humans, as the foot is consumed. The shell can be used for jewelry and decorative objects. Native Americans have used all parts of the abalone: the meat as food, and the shell for tools, trade, and decorations. There has been no commercial fishery since the dismantling of the commercial fishing companies that hunted red abalone. Due to its economic importance to humans, the green abalone has been raised in aquaculture since 1940, first at Stanford's Hopkins Marine Station in Pacific Grove, California, and more recently at various coastal facilities within southern California, primarily for the overseas restaurant trade. (Anderson, 2003; McBride and Conte, 2010)

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

There are no known adverse effects of Haliotis fulgens on humans.

Conservation Status

Haliotis fulgens has been a species of concern since 2004 because of over-harvesting. Population size has been reduced because of over-fishing. The populations of green abalone unfortunately are extremely low and there are many legal protections in effect. Some of these have closed commercial and recreational fisheries, and an Abalone Recovery Management Plan has been implemented through the state of California. (Gruenthal, 2007; Neuman, 2009)

Contributors

Joshua Williams (author), San Diego Mesa College, Sarah Yesil (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, Angela Miner (editor), Animal Diversity Web Staff.

Glossary

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

benthic

Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

macroalgae

seaweed. Algae that are large and photosynthetic.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

References

1996. "Abalone Growth and Development" (On-line). OceanLink. Accessed May 17, 2013 at http://oceanlink.info/Conservation/abalone/BHCAP/development.html.

2003. "Abalone: Reproduction and Growth" (On-line). Marine Science. Accessed May 16, 2013 at http://www.marinebio.net/marinescience/06future/abrepro.htm.

2007. "Predators & Defenses" (On-line). Abalone. Accessed May 17, 2013 at http://www.asnailsodyssey.com/LEARNABOUT/ABALONE/abalPhyDef.php.

Anderson, G. 2003. "Abalone: Species Diversity" (On-line). Marine Science. Accessed April 03, 2013 at http://www.marinebio.net/marinescience/06future/abspdiv.htm.

Buchsbaum, R., L. Milne. 1960. The Lower Animals: Living Invertebrates of the World. Garden City, New York: Doubleday & Company, Inc..

Gruenthal, K. 2007. Conservation Genetics of California Abalone Species Dissertation. Ann Arbor, MI: ProQuest Information and Learning Company. Accessed February 19, 2013 at http://proquest.umi.com/pqdlink?did=1342732321&Fmt=7&clientI d=79356&RQT=309&VName=PQD.

Handorf, P. 2000. "Abalone Identification Guide" (On-line). California Department of Fish and Wildlife. Accessed March 15, 2013 at http://www.dfg.ca.gov/marine/ab_id.asp.

Johnstone, K. 1957. Sea Treasure: A Guide to Shell Collecting. Boston, Massachusetts: Houghton Mifflin Company Boston.

MacGinitie, G., N. MacGinitie. 1949. Natural History of Marine Animals. United States: McGraw-Hill Book Company, Inc.

McBride, S., F. Conte. 2010. "California Abalone Aquaculture" (On-line pdf). aqua.ucdavis.edu. Accessed May 18, 2013 at http://aqua.ucdavis.edu/DatabaseRoot/pdf/ASAQ-A10.PDF.

Neuman, M. 2009. "Species of Concern: Green Abalone" (On-line). National Marine Fisheries Service. Accessed February 19, 2013 at http://www.nmfs.noaa.gov/pr/pdfs/species/greenabalone_detailed.pdf.

Perez-Estrada, C., R. Civera, A. Hernandez-Llamas, E. Serviere-Zaragoza. 2011. Growth and biochemical composition of juvenile green abalone Haliotis fulgens fed rehydrated macroalgae. Aquaculture Nutrition, 17/2: 62-69.

Riffell, J., P. Krug, R. Zimmer. 2002. Fertilization in the sea: the chemical identity of an abalone sperm attractant. The Journal of Experimental Biology, 205: 1439-1450. Accessed April 24, 2013 at http://instructional1.calstatela.edu/pkrug/lab/PDF/2002,%20Riffell%20et%20al.pdf.

Sheets, E. 1974. The Fascinating World of the Sea. New York City, New York: Crown Publishers, Inc..

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