Common names for abalones also include ear-shells, sea-ears and Venus's-ears, as well as muttonfish or muttonshells in Australia, ormer in Jersey and Guernsey, perlemoen in South Africa and pāua in New Zealand.
There is only the one genus in the family Haliotidae, and about four to seven subgenera. The number of species recognized worldwide ranges from about 100 to 130 (due to the occurrence of hybrids).
The shells of abalones have a low and open spiral structure, and are characterized by several respiratory holes in a row near the shell's outer edge. The thick inner layer of the shell is composed of nacre or mother-of-pearl, which in many species is highly iridescent, giving rise to a range of strong and changeable colors, which make the shells attractive to humans as decorative objects, and as a source of colorful mother-of-pearl.
The flesh (the adductor muscle) of abalones is widely considered to be a desirable food.
The color of the shell is very variable from species to species. The iridescent nacre that lines the inside of the shell varies in color from silvery white, to pink, red and green-red, through to Haliotis iris, which shows predominantly deep blues, greens and purples.
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 larvae are lecithotrophic or feed off a yolk sac. The adults are herbivorous and feed with their rhipidoglossan radula on macroalgae, preferring red algae. Sizes vary from 20 mm (Haliotis pulcherrima) to 200 mm (or even more) (Haliotis rufescens).
The majority of abalone species are found in cold waters, off the Southern Hemisphere coasts of New Zealand, South Africa and Australia, and Western North America and Japan in the Northern Hemisphere.
The species of sea snail which is known in the sea food trade as the "Chilean abalone", Concholepas concholepas, is from another family altogether. It is not a true abalone at all, but a muricid, or rock snail.
The highly iridescent inner nacre layer of the shell of abalone has traditionally been used as a decorative item in jewelry, buttons, and as inlay in furniture and in musical instruments such as guitars, etc.
The dust created through the grinding and cutting of abalone shell is dangerous; appropriate safeguards should be taken to protect a person from inhaling these particles. An N95-rated dust respirator, a ventilation system, and wet grinding are requirements to working the shell safely. The calcium carbonate is a respiratory irritant and the particles can penetrate into the lower respiratory tree and cause irritant bronchitis and other respiratory irritation responses. The usual symptoms are cough and sputum production, and secondary infections can occur. If there are proteins left in the shell matrix, it is also possible that they can trigger an allergic (asthmatic) attack. In general, the more someone is exposed to something that triggers their asthma reaction, the larger the reaction. Allergic skin reactions can also occur.
Tasmania provides approximately 25% of the yearly world abalone harvest. Around 12500 tasmanians recreationally fish for blacklip and greenlip abalone. For blacklip abalone, the size limit varies from between 138mm for the southern end of the state and 127mm for the northern end of the state. Greenlip abalone have a minimum size of 145mm, except for an area around Perkin's Bay in the north of the state where the minimum size is 132 mm. With a recreational abalone licence, there is a bag limit of 10 per day, and a total possession limit of 20.
Sport harvesting of red abalone is permitted with a California fishing license and an abalone stamp card. New in 2008, the abalone card also comes with a set of 24 tags. Legal-size abalone must be tagged immediately. Abalone may only be taken using breath-hold techniques or shorepicking; scuba diving for abalone is strictly prohibited. Taking of abalone is not permitted south of the mouth of the San Francisco Bay. There is a size minimum of seven inches measured across the shell and a quantity limit of three per day and 24 per year. A person may be in possession of only three abalone at any given time.
Abalone may only be taken from April to November, not including July. Transportation of abalone may only legally occur while the abalone is still attached in the shell. Sale of sport-obtained abalone is illegal, including the shell. Only red abalone may be taken; black, white, pink, and flat abalone are protected by law.
An abalone diver is normally equipped with a thick wetsuit, including a hood, booties, and gloves, and usually also a mask, snorkel, weight belt, abalone iron, and abalone gauge. Alternatively, the rock picker can feel underneath rocks at low tides for abalone. Abalone are mostly taken in depths from a few inches up to 10 m (33 ft); less common are freedivers who can work deeper than 10 m (33 ft). Abalone are normally found on rocks near food sources (kelp). An abalone iron is used to pry the abalone from the rock before it can fully clamp down. Divers commonly dive out of boats, kayaks, tube floats or directly off the shore. An eight-inch abalone is considered a good catch, a nine-inch abalone extremely good, and a ten-inch or larger abalone a trophy catch.
There has been a trade in diving to catch abalones off parts of the United States coast from before 1939. In World War II, many of these abalone divers were recruited into the United States armed forces and trained as frogmen.
The largest abalone recorded in California is 12.34 inches, caught by John Pepper somewhere off the coast of Humboldt county.
Highly polished New Zealand pāua shells are extremely popular as souvenirs with their striking blue, green, and purple iridescence. Transporting unprocessed abalone shells out of New Zealand is illegal.
For the last few years, however, no permits have been issued for collecting Abalone (Perlemoen), but commercial harvesting still continues as does illegal collection by syndicates. In 2007, because of widespread poaching of abalone, the South African government listed perlemoen as an endangered species according to the CITES section III appendix, which requests member governments to monitor the trade in this species. The abalone meat from South Africa is prohibited for sale in the country to help reduce poaching -- however, much of the illegally harvested meat is sold in Asian countries. As of early 2008, the wholesale price for abalone meat was approximately US$40.00 per kilogram. There is an active trade in the shells which sell for more than US$1,400 per metric tonne. There is, however, speculation that local criminal gangs barter Abalone illegally with Chinese nationals in exchange for chemicals used in the production of drugs, reducing the need for the use of money and hence avoiding money laundering issues.
The meat of this mollusk is considered a delicacy in certain parts of Latin America (especially Chile), New Zealand, South East Asia, and East Asia (especially in China, Japan, and Korea). In Chinese speaking regions, abalone are commonly known as bao yu, and sometimes forms part of a Chinese banquet. Similar to shark fin soup, it is considered a symbol of wealth and prestige, and is traditionally reserved for special occasions such as weddings and other celebrations. However, the availability of commercially farmed abalone has allowed more common consumption of this once rare delicacy.