Abalone shells are the protective outer layer of a large marine snail, a type of gastropod mollusk belonging to the genus Haliotis. The shell’s interior is composed of nacre, commonly called mother-of-pearl, which is a naturally strong material made of calcium carbonate and proteins. This striking, changeable color makes the shells highly attractive for jewelry and decorative arts. They are highly prized for their beauty and for the meat of the animal they protect.
The Source of the Shell
Abalone shells are the exoskeleton of the living sea snail, growing along with the organism throughout its life. The shell serves as a defense mechanism, protecting the soft-bodied animal from predators such as sea otters, crabs, and octopuses. The animal clings tightly to rocks using a powerful, muscular foot, allowing it to clamp down and making removal nearly impossible when disturbed. Shells are typically encountered after the animal has been consumed, either by natural predators or by humans. The shells also feature a row of holes along the edge, which are used by the animal for respiration, waste removal, and releasing gametes.
Global Geographical Range
The distribution of abalone species is extensive, covering the coastal waters of nearly every continent, with the majority concentrated in cold and temperate regions. A significant concentration exists along the Pacific Coast of North America, ranging from Alaska down to Baja California, Mexico. This region hosts several distinct species, including the Red Abalone (Haliotis rufescens), the largest in the world.
Major global hotspots include:
- The waters around Australia and New Zealand, featuring species like the Greenlip, Blacklip, and New Zealand’s Blackfoot Paua (Haliotis iris).
- South Africa, particularly for the species known as perlemoen (Haliotis midae), found along its southern-eastern coast.
- Japan, where they are known as awabi, and parts of the Mediterranean and Eastern Atlantic.
Species diversity is high across the Indo-West Pacific. Notably, the Atlantic coast of North America and the Pacific coast of South America largely lack native abalone populations.
Specific Environmental Habitats
Abalone are marine bottom-dwellers, and their survival depends on specific ecological conditions. They predominantly inhabit shallow, rocky substrates in coastal waters, where the hard surfaces allow them to adhere firmly with their muscular foot. This rocky environment provides necessary protection and crevices for juvenile abalone.
The species thrive in cold, temperate waters, which concentrates their populations in regions with cool ocean currents. Their diet consists almost exclusively of algae, making them most abundant in areas that support dense growth of large seaweeds, such as kelp forests. The animals are sedentary, clinging to their chosen rock and waiting for pieces of kelp to drift by.
Most abalone live in the subtidal zone, typically ranging from a few feet below the low-tide mark down to about 100 feet in depth. While some species can be found in the intertidal zone, others, like the White Abalone, are found much deeper, usually between 50 and 180 feet. Depth distribution varies based on local factors such as water temperature and food availability.