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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).
[edit] Distribution
The haliotid family has a worldwide distribution, along the coastal waters of every continent, except the Atlantic coast of South America, the Caribbean, and the East Coast of the United States.
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.
[edit] Human use
Abalone has long been a valuable food source for humans in every area of the world where a species is, or used to be, abundant. The various larger species of abalones have been exploited commercially for food to the extent that many populations are now severely threatened.
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...