Haliotis

For the human use of Haliotis molluscs, see Abalone.

Not to be confused with Halitosis.

Haliotis Temporal range:
Living abalone in tank showing epipodium and tentacles, anterior end to the right.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Vetigastropoda
Order:	Lepetellida
Superfamily:	Haliotoidea
Family:	Haliotidae Rafinesque, 1815
Genus:	Haliotis Linnaeus, 1758
Type species
Haliotis asinina Linnaeus, 1758
Synonyms
Euhaliotis Wenz, 1938 Eurotis Habe & Kosuge, 1964 Exohaliotis Cotton & Godfrey, 1933 Haliotis (Haliotis) Linnaeus, 1758 Haliotis (Marinauris) Iredale, 1937 Haliotis (Nordotis) Habe & Kosuge, 1964 Haliotis (Notohaliotis) Cotton & Godfrey, 1933 Haliotis (Padollus) Montfort, 1810 Haliotis (Paua) C. Fleming, 1953 Haliotis (Sulculus) H. Adams & A. Adams, 1854 Marinauris Iredale, 1927 Neohaliotis Cotton & Godfrey, 1933 Nordotis Habe & Kosuge, 1964 Notohaliotis Cotton & Godfrey, 1933 Ovinotis Cotton, 1943 Padollus Montfort, 1810 Paua C. Fleming, 1953 Sanhaliotis Iredale, 1929 Schismotis Gray, 1856 Teinotis H. Adams & A. Adams, 1854 Tinotis P. Fischer, 1885 (invalid: unjustified emendation of Teinotis) Usahaliotis Habe & Kosuge, 1964

Haliotis, common name abalone, is the only genus in the family Haliotidae.

This genus once contained six subgenera. These subgenera have become alternate representations of Haliotis. The genus consists of small to very large, edible, herbivorous sea snails, marine gastropod molluscs. The number of species recognized worldwide ranges between 30 and 130, with over 230 species-level taxa described. The most comprehensive treatment of the family considers 56 species valid, with 18 additional subspecies.

Other common names are ear shells, sea ears, and, rarely, muttonfish or muttonshells in parts of Australia, ormer in the UK, perlemoen in South Africa, and the Māori name for three species in New Zealand is pāua.

Description

The iridescent inside surface of a red abalone shell from Northern California: The coin is about one inch in diameter.

The shells of abalones have a low, open, spiral structure, and are characterized by having several open respiratory pores in a row near the shell's outer edge. The thick inner layer of the shell is composed of nacre, which in many species of abalone is highly iridescent, giving rise to a range of strong, changeable colors, which make the shells attractive to humans as decorative objects, in jewelry, and as a source of colorful mother-of-pearl.

The shell of abalones is convex, rounded to oval shape, and may be highly arched or very flattened. The shell of the majority of species is ear-shaped, presenting a small, flat spire and two to three whorls. The last whorl, known as the body whorl, is auriform, meaning that the shell resembles an ear, giving rise to the common name "ear shell". Haliotis asinina has a somewhat different shape, as it is more elongated and distended. The shell of Haliotis cracherodii cracherodii is also unusual as it has an ovate form, is imperforate, shows an exserted spire, and has prickly ribs.

A mantle cleft in the shell impresses a groove in the shell, in which are the row of holes (known as tremata), characteristic of the genus. These holes are respiratory apertures for venting water from the gills and for releasing sperm and eggs into the water column. They make up what is known as the selenizone which forms as the shell grows. This series of eight to 38 holes is near the anterior margin. Only a small number are generally open. The older holes are gradually sealed up as the shell grows and new holes form. Therefore, the number of tremata is not characteristic for the species. Each species has a number of open holes, between four and 10, in the selenizone. This number is not fixed and can vary within a species and between populations. Abalones have no operculum. The aperture of the shell is very wide and nacreous.

The exterior of the shell is striated and dull. The color of the shell is very variable from species to species, which may reflect the animal's diet. The iridescent nacre that lines the inside of the shell varies in color from silvery white, to pink, red and green-red, to deep blue, green to purple.

The animal shows fimbriated head-lobes. The side-lobes are also fimbriated and cirrated. The rounded foot is very large. The radula has small median teeth, and the lateral teeth are single and beam-like. About 70 uncini are present, with denticulated hooks, the first four very large. The soft body is coiled around the columellar muscle, and its insertion, instead of being on the columella, is on the middle of the inner wall of the shell. The gills are symmetrical and both well developed.

These snails cling solidly with their broad muscular foot to rocky surfaces at sublittoral depths, although some species such as Haliotis cracherodii used to be common in the intertidal zone. Abalones reach maturity at a relatively small size. Their fecundity is high and increases with their size (from 10,000 to 11 million eggs at a time). The spermatozoa are filiform and pointed at one end, and the anterior end is a rounded head.

The larvae are lecithotrophic. The adults are herbivorous and feed with their rhipidoglossan radula on macroalgae, preferring red or brown algae. Sizes vary from 20 mm (25⁄32 in) (Haliotis pulcherrima) to 200 mm (7 7⁄8 in), while Haliotis rufescens is the largest of the genus at 30 cm (12 in).

By weight, about one-third of the animal is edible meat, one-third is offal, and one-third is shell.

Structure and properties of the shell

The shell of the abalone is exceptionally strong and is made of microscopic calcium carbonate tiles stacked like bricks. Between the layers of tiles is a clingy protein substance. When the abalone shell is struck, the tiles slide instead of shattering and the protein stretches to absorb the energy of the blow. Material scientists around the world are studying this tiled structure for insight into stronger ceramic products such as body armor. The dust created by grinding and cutting abalone shell is dangerous; appropriate safeguards must be taken to protect people from inhaling these particles. There is much discussion of this topic online.

Species

The number of species that are recognized within the genus Haliotis has fluctuated over time, and depends on the source that is consulted. The number of recognized species ranges from 30 to 130. This list finds a compromise using the "WoRMS" database, plus some species that have been added, for a total of 57. The majority of abalone have not been evaluated for conservation status. Those that have been reviewed tend to show that the abalone in general is declining in numbers, and will need protection throughout the globe.

Extant species

Species of abalone

Species	Range	Conservation status
Haliotis alfredensis Bartsch, 1915	South Africa	DD IUCN
Haliotis arabiensis Owen, Regter & Van Laethem, 2016	Off Yemen and Oman	NT IUCN
Haliotis asinina Linnaeus, 1758	Philippines; Indonesia; Australia; Japan; Thailand; Vietnam	LC IUCN
Haliotis australis Gmelin, 1791	New Zealand	LC IUCN
Haliotis brazieri Angas, 1869	Eastern Australia	NT IUCN
Haliotis clathrata Reeve, 1846	Seychelles; Comores; Madagascar; Mauritius; Kenya	LC IUCN
Haliotis coccoradiata Reeve, 1846	Eastern Australia	LC IUCN
Haliotis corrugata Wood, 1828	California, USA; Baja California, Mexico	CR IUCN, Species of Concern National Marine Fisheries Service; Vulnerable (global) and imperiled (California) California Department of Fish and Wildlife
Haliotis cracherodii Leach, 1814	California, USA; Baja California, Mexico	CR IUCN, Vulnerable (Global, Nation: US, State: California) California Department of Fish and Wildlife; Listed endangered National Marine Fisheries Service
Haliotis cyclobates Péron & Lesueur, 1816	Southern Australia	LC IUCN
Haliotis dalli Henderson, 1915	Galapagos Islands, western Colombia	DD IUCN
Haliotis discus Reeve, 1846	Japan; South Korea	EN IUCN
Haliotis dissona (Iredale, 1929)	Australia; New Caledonia	LC IUCN
Haliotis diversicolor Reeve, 1846	Japan; Australia; Southeast Asia	DD IUCN
Haliotis drogini Owen & Reitz, 2012	Cocos Island	VU IUCN
Haliotis elegans Koch & Philippi, 1844	Western Australia	LC IUCN
Haliotis exigua Dunker, R.W., 1877 (synonym of H. diversicolor)	Japan	Not evaluated
Haliotis fatui Geiger, 1999	Tonga Mariana Islands	DD IUCN
Haliotis fulgens Philippi, 1845	California, USA; Baja California, Mexico	CR IUCN, Vulnerable (Global, State: California California Department of Fish and Wildlife); Species of Concern NMFS
Haliotis geigeri Owen, 2014	São Tomé and Príncipe Islands	VU IUCN
Haliotis gigantea Gmelin, 1791	Japan	EN IUCN
Haliotis glabra Gmelin, 1791	Philippines; Vietnam	LC IUCN
Haliotis iris Gmelin, 1791	New Zealand	LC IUCN
Haliotis jacnensis Reeve, 1846	Japan; Nicobar Islands; Ryukyu Islands; Pacific Islands;	LC IUCN
Haliotis kamtschatkana Jonas, 1845	Western North America	EN IUCN, Imperiled (Alaska, British Columbia), Vulnerable (global, US), critically imperiled (California); Species of Concern NMFS
Haliotis laevigata Donovan, 1808	South Australia; Tasmania	VU IUCN
Haliotis madaka (Habe, 1977)	Japan; South Korea	EN IUCN
Haliotis mariae Wood, 1828	Oman; Yemen	EN IUCN
Haliotis marmorata Linnaeus, 1758	Liberia; Ivory Coast; Ghana	LC IUCN
Haliotis melculus (Iredale, 1927)	Australia (New South Wales, Queensland)	VU IUCN
Haliotis midae Linnaeus, 1758	South Africa	EN IUCN
Haliotis mykonosensis Owen, Hanavan & Hall, 2001	Greece; Turkey; Tunisia	LC IUCN
Haliotis ovina Gmelin, 1791	Thailand; Vietnam; southern part of the Pacific Ocean; Andaman Islands; Maldives; Ryukyu Islands	LC IUCN
Haliotis papulata Reeve, 1846	Australia; Papua New Guinea; Philippines; Sri Lanka; Thailand	LC IUCN
Haliotis parva Linnaeus, 1758	South Africa; Angola	DD IUCN
Haliotis pirimoana Walton, Marshall, Rawlence & Spencer, 2024	Manawatāwhi / Three Kings Islands, New Zealand	Not evaluated
Haliotis planata G. B. Sowerby II, 1882	Ryukyu Islands; Sri Lanka; Indonesia; Fiji; Andaman Sea	LC IUCN
Haliotis pourtalesii Dall, 1881	Eastern USA; Gulf of Mexico; Eastern South America; northern Colombia	DD IUCN
Haliotis pulcherrima Gmelin, 1791	Polynesia	DD IUCN
Haliotis queketti E.A. Smith, 1910	Eastern Africa	DD IUCN
Haliotis roei Gray, 1826	Australia	NT IUCN
Haliotis rubiginosa Reeve, 1846	Lord Howe Island	CR IUCN
Haliotis rubra Leach, 1814	Southern and Eastern Australia	VU IUCN
Haliotis rufescens Swainson, 1822	Western North America	CR IUCN, apparently secure (global, US); critically imperiled (Canada)
Haliotis rugosa Lamarck, 1822	South Africa; Madagascar; Mauritius; Red Sea	LC IUCN
Haliotis scalaris (Leach, 1814)	Southern and Western Australia	LC IUCN
Haliotis semiplicata Menke, 1843	Western Australia	LC IUCN
Haliotis sorenseni Bartsch, 1940	California, USA; Baja California, Mexico	CR IUCN, critically imperiled (global, US, California); Endangered NMFS
Haliotis spadicea Donovan, 1808	South Africa	LC IUCN
Haliotis speciosa Reeve, 1846 (synonym of H. tuberculata)	Eastern South Africa	Not evaluated
Haliotis squamosa Gray, 1826	Southern Madagascar	DD IUCN
Haliotis stomatiaeformis Reeve, 1846	Malta; Sicily	VU IUCN
Haliotis supertexta Lischke, 1870 (synonym of H. diversicolor)	Japan; Sao Tome	Not evaluated
Haliotis thailandis Dekker & Patamakanthin, 2001 (synonym of H. papulata)	Andaman Sea	Not evaluated
Haliotis tuberculata Linnaeus, 1758	Ireland (introduced); Channel Islands; Azores; Canary Islands; Madeira ; Brittany; Great Britain	VU IUCN
Haliotis unilateralis Lamarck, 1822	Gulf of Aqaba; East Africa; Seychelles;	LC IUCN
Haliotis varia Linnaeus, 1758	Mascarene Basin; Red Sea; Sri Lanka; Western Pacific;	LC IUCN
Haliotis virginea Gmelin, 1791	New Zealand; Chatham Islands; Auckland Islands; Campbell Island	LC IUCN
Haliotis walallensis Stearns, 1899	Western North America	CR IUCN

• 
  A dorsal view of a live ass's ear abalone, Haliotis asinina
• 
  the pink abalone, Haliotis corrugata
• 
  The black abalone, Haliotis cracherodii
• 
  Dorsal (left) and ventral (right) views of the blacklip abalone, Haliotis rubra
• 
  The white abalone, Haliotis sorenseni
• 
  A shell of Haliotis varia form dohrniana

• 
  Haliotis asinina
• 
  Haliotis australis
• 
  Haliotis clathrata
• 
  Haliotis coccoradiata
• 
  Haliotis corrugata
• 
  Haliotis cracherodii
• 
  Haliotis cyclobates
• 
  Haliotis discus discus
• 
  Haliotis diversicolor
• 
  Haliotis elegans
• 
  Haliotis fatui
• 
  Haliotis fulgens fulgens
• 
  Haliotis gigantea f. sieboldii
• 
  Haliotis glabra
• 
  Haliotis iris
• 
  Haliotis jacnensis
• 
  Haliotis kamtschatkana assimilis (South California).
• 
  Haliotis laevigata (South Australia).
• 
  Haliotis madaka
• 
  Haliotis mariae
• 
  Haliotis marmorata
• 
  Haliotis midae
• 
  Haliotis ovina
• 
  Haliotis parva
• 
  Haliotis planata
• 
  Haliotis pulcherrima
• 
  Haliotis queketti
• 
  Haliotis roei
• 
  Haliotis rubra
• 
  Haliotis rufescens
• 
  Haliotis rugosa
• 
  Haliotis scalaris
• 
  Haliotis semiplicata
• 
  Haliotis sorenseni
• 
  Haliotis spadicea
• 
  Haliotis squamosa
• 
  Haliotis stomatiaeformis
• 
  Haliotis supertexta
• 
  Haliotis thailandis
• 
  Haliotis tuberculata (Europe)
• 
  Haliotis unilateralis
• 
  Haliotis varia
• 
  Haliotis virginea
• 
  Haliotis walallensis

Fossil species

• †Haliotis benoisti Cossmann, 1896 (Aquitaine, France)
• †Haliotis flemingi Powell, 1938 (New Zealand)
• †Haliotis lomaensis Anderson, 1902
• †Haliotis mathesonensis (Eagle, 1996)
• †Haliotis (Marinauris) matihetihensis (Eagle, 1999)
• †Haliotis powelli C. A. Fleming, 1952
• †Haliotis stalennuyi Owen & Berschauer, 2017
• †Haliotis volhynica Eichwald, 1829
• †Haliotis waitemataensis Powell, 1938

Conservation

Over half of the modern Haliotis species with sufficient data are considered threatened to some extent on the IUCN Red List, with all but one species from the Pacific coast of North America being critically endangered as a consequence of massive historical overharvesting, withering abalone syndrome, and recent marine heatwaves which have caused collapses of both abalones and their habitat. Haliotis species from elsewhere are also threatened by overexploitation and climate change. In addition, abalones as a whole are considered highly vulnerable to ocean acidification due to their accretion of aragonite and dependence on susceptible coralline algae for development, and thus may eventually go extinct unless the rate of ocean acidification is arrested.

Synonyms

Main article: List of abalone synonyms

See also

• Abalone
• Concholepas concholepas
• Pāua

Sources

• Abbott, R. Tucker; Dance, S. Peter (2000). Compendium of Seashells (4th ed.). Odyssey Publishing. pp. 19–23. ISBN 978-0-9661720-0-3.
• Anon (2014c). "Haliotis kamtschatkana – Jonas, 1845". NatureServe Explorer. Archived from the original on 26 August 2014. Retrieved 22 August 2014.
• Anon (2014d). "Haliotis refescens – Swainson, 1822". NatureServe Explorer. Archived from the original on 26 August 2014. Retrieved 22 August 2014.
• Anon (2014e). "Haliotis sorenseni – Bartsch, 1940". NatureServe Explorer. Archived from the original on 26 August 2014. Retrieved 22 August 2014.
• Anon (2014f). "Haliotis cracherodii – Leach, 1814". NatureServe Explorer. Archived from the original on 26 August 2014. Retrieved 22 August 2014.
• Anon (14 January 2009). "Endangered and Threatened Species; Endangered Status for Black Abalone". Federal Register: The Daily Journal of the United States. Archived from the original on 26 August 2014. Retrieved 22 August 2014.
• Anon (29 May 2001). "Endangered and Threatened Species; Endangered Status for White Abalone". Federal Register: The Daily Journal of the United States. Archived from the original on 29 July 2014. Retrieved 22 August 2014.
• Beesley, P. L.; Ross, G. J. B.; Wells, A. (1998). Mollusca: The Southern Synthesis: An Essential Reference. Melbourne, Australia: CSIRO Publishing. pp. 667–669. ISBN 978-0-643-05756-2.
• Cox, Keith W. (1962). "California abalone, family Haliotidae". The Resources Agency of California Department of Fish and Game: Fish Bulletin. 118. ISSN 6306-2593.
• Dauphin, Y.; Cuif, J. P.; Mutvei, H.; Denis, A. (1989). "Mineralogy, Chemistry and Ultrastructure of the External Shell-layer in Ten Species of Haliotis With Reference to Haliotis tuberculata (Mollusca, Archaeogastropoda)". Bulletin of the Geological Institutions of the University of Uppsala. 15: 7–38. ISSN 0302-2749.
• EoL (2014). "Haliotis speciosa: Splendid Abalone". Encyclopedia of Life. Archived from the original on 21 August 2014. Retrieved 21 August 2014.
• Geiger, Daniel L.; Groves, Lindsey T. (September 1999). "Review of Fossil Abalone (Gastropoda, Vetigastropoda, Haliotidae) with Comparison to Recent Species". Journal of Paleontology. 73 (5): 872–885. doi:10.1017/S0022336000040713. ISSN 0022-3360. S2CID 87537607.
• Gofas, Serge; Tran, Bastien; Bouchet, Phillippe (2014). "WoRms Taxon Details: Haliotis Linnaeus, 1758". WoRMS (World Register of Marine Species). Archived from the original on 10 October 2014. Retrieved 16 August 2014.
• Gustafson, Rick; Rumsey, Scott (1 November 2007). "Species of Concern: Pinto Abalone Haliotis Kamtschatkana" (PDF). NOAA: National Marine Fisheries Service. Archived (PDF) from the original on 7 October 2012. Retrieved 22 August 2014.
• Hoiberg, Dale H., ed. (1993). "The New Encyclopaedia Britannica". Encyclopædia Britannica. Vol. 1: A-ak Bayes (15th ed.). Chicago, IL: Encyclopædia Britannica, Inc. ISBN 978-0-85229-961-6. LCCN 2002113989.
• Lin, Albert; Meyers, Marc André (15 January 2005). "Growth and Structure in Abalone Shell". Materials Science and Engineering: A. 390 (1–2): 27–41. doi:10.1016/j.msea.2004.06.072. ISSN 0921-5093.
• Neuman, Melissa (10 June 2009). "Species of Concern: Green Abalone Haliotis fulgens" (PDF). NOAA: National Marine Fisheries Service. Archived (PDF) from the original on 4 March 2016. Retrieved 22 August 2014.
• Neuman, Melissa (2 November 2007). "Species of Concern: Pink Abalone Haliotis corrugata" (PDF). NOAA: National Marine Fisheries Service. Archived (PDF) from the original on 4 March 2016. Retrieved 22 August 2014.
• State of California (January 2011). "Special Animals (898 Taxa)" (PDF). State of California: Division of Fish and Game. Archived from the original (PDF) on 24 January 2014. Retrieved 22 August 2014.
• Tran, Bastien; Bouchet, Phillippe (2009). "WoRMS Taxon Details: Haliotis corrugata oweni Talmadge, 1966". WoRMS: World Register of Marine Species. Archived from the original on 17 October 2014. Retrieved 19 August 2014.
• Linnaeus, C. 1758. Systema Naturae per Regna tria Naturae, secundem Classes, Ordines, Genera, Species, cum Characteribus, Differentis, Synonymis, Locis. Tom.1 Editio decima, reformata. Holmiae : Laurentii Salvii 824 pp.
• Iredale, T. 1927. Caloundra Shells. The Australian Zoologist 4: 331–336, pl. 46
• Iredale, T. 1929. Queensland molluscan notes, No. 1. Memoirs of the Queensland Museum 9(3): 261–297, pls 30-31
• Cotton, B.C. & Godfrey, F.K. 1933. South Australian Shells. Part 9. South Australian Naturalist 15(1): 14-24
• Cotton, B.C. 1943. Australian Shells of the Family Haliotidae. Transactions of the Royal Society of South Australia 67(1): 175-180
• Moore, R.C. (ed.) 1960. Treatise on Invertebrate Paleontology. Part I. Mollusca 1. Boulder, Colorado & Lawrence, Kansas : Geological Society of America & University of Kansas Press xxiii 351 pp.
• Wilson, B. 1993. Australian Marine Shells. Prosobranch Gastropods. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 pp.
• Geiger, D.L. & Poppe, G.T. 2000. A Conchological Iconography. The family Haliotidae. Germany : ConchBooks 135 pp.
• Bouchet, P.; Gofas, S. (2014). Haliotis Linnaeus, 1758. Accessed through: World Register of Marine Species
• Tryon, George W. Jr. (1880). Manual of Conchology; Structural and Systematic With Illustrations of the Species (PDF). Vol. II: Muricinæ, Purpurinæ. Philadelphia, PA: Academy of Natural Sciences.