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Abalone

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Abalone are marine gastropod mollusks belonging to the genus Haliotis. They are the only members of the family Haliotidae. These sea snails are found in coastal waters across nearly every continent. They are absent from the Pacific coast of South America, the Arctic, and Antarctica. Abalone are highly valued by humans for their meat and their beautiful shells.

AbaloneInside
AbaloneInside

Many cultures consider their flesh a luxury delicacy. Because of this, they have been harvested since prehistory.

The anatomy of an abalone is built for survival on rocky surfaces. Most species possess a shell that is convex and oval in shape. The last whorl of the shell is called the body whorl. This part is auriform, which means it resembles the shape of an ear. This characteristic gives rise to the common name "ear shell."

Abalone Santo Andre Povoa de Varzim
Abalone Santo Andre Povoa de Varzim

The shell features a row of holes known as the selenizone. These respiratory apertures allow the snail to vent water from its gills. They also serve as channels for releasing sperm and eggs into the water column. As the animal grows, it creates new holes near the margin. The older holes are gradually sealed up by the expanding shell. Most species maintain between four and ten open holes at any time.

The internal structure of the shell is a marvel of natural engineering. The thick inner layer consists of nacre, a substance often called mother-of-pearl. This nacre is highly iridescent and displays colors like pink, green, blue, and purple.

Carving of chief (detail), Haida, c. 1890, wood, paint, abalone shell - Fairbanks Museum and Planetarium - DSC04327
Carving of chief (detail), Haida, c. 1890, wood, paint, abalone shell - Fairbanks Museum and Planetarium - DSC04327

The shell is exceptionally strong due to a tightly packed calcium carbonate matrix. An endogenous protein is layered within this matrix to provide extra strength. This unique structure prevents the shell from shattering under direct force. Instead, the layers are more likely to shed. Material scientists study this mechanism to develop better protective tools like body armor.

Species within the genus Haliotis vary significantly in size and form. Most abalone are relatively small, but the genus includes much larger varieties. The largest species is Haliotis rufescens, which can reach 36 inches in length. Other species, such as Haliotis pulcherrima, are much smaller. Some species have unusual shapes, like the ovate and prickly Haliotis cracherodii cracherodii. The exterior of the shell is typically dull and striated. The color of the exterior can vary based on the animal's diet.

Evolutionary history suggests that abalone have existed for a very long time. The earliest known fossils date back to the Campanian age of the Late Cretaceous. These fossils have been found in North America, which may suggest a regional origin. However, some scientists suggest a central Indo-Pacific origin instead. This theory is supported by the high diversity of species found in that region today. Abalone belong to the clade Vetigastropoda, though their exact relationship to other groups remains a subject of study.

Human interaction with abalone has changed significantly over the millennia. Archaeological evidence shows shells were used 100,000 years ago at Blombos Cave in South Africa. In the United States, abalone was once gathered by Native American tribes and Chinese immigrants. By the 1920s, a small portion of abalone cost the equivalent of about US$7. By 2004, the price for a restaurant portion had risen to US$75.

Japanese Abalone Diver
Japanese Abalone Diver

To protect wild stocks from overfishing and poaching, humans have turned to aquaculture.

Abalone-farm1web
Abalone-farm1web

Commercial farming began in Japan and China during the late 1950s and 1960s. Today, farmed abalone provides most of the meat consumed globally.

Modern farming techniques include complex systems like the "sea ranch" in Western Australia.

Alaminosjf385
Alaminosjf385

Established in 2012, this ranch uses 5,000 concrete habitat units on an artificial reef. These units can host up to 400 abalone each. Young abalone are moved to these reefs from onshore hatcheries.

Alaminosjf384
Alaminosjf384

The abalone feed on seaweed that grows naturally on these structures. This method helps support a larger ecosystem, including fish like pink snapper and wrasse. Such efforts are vital as wild populations face threats from disease and habitat loss.

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🖼️ Images & Media (9)
File:AbaloneInside.jpg
AbaloneInside.jpg
File:Abalone Santo Andre Povoa de Varzim.jpg
Abalone Santo Andre Povoa de Varzim.jpg
File:Abalone-farm1web.jpg
Abalone-farm1web.jpg
File:Alaminosjf384.JPG
Alaminosjf384.JPG
File:Alaminosjf385.JPG
Alaminosjf385.JPG
File:Workers drying abalone shells in the sun in southern California (CHS-1399).jpg
Workers drying abalone shells in the sun...
File:Japanese Abalone Diver.jpg
Japanese Abalone Diver.jpg
File:White abalone Haliotis sorenseni.jpg
White abalone Haliotis sorenseni.jpg
File:Carving of chief (detail), Haida, c. 1890, wood, paint, abalone shell - Fairbanks Museum and Planetarium - DSC04327.JPG
Carving of chief (detail), Haida, c....
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