What Divers Should Know About Abalone

Abalone are typically found clinging to rocky surfaces in sublittoral depths. These marine snails, from the genus Haliotis, are globally distributed in coastal waters, with a majority thriving in colder regions like New Zealand, South Africa, Australia, and Western North America. Their distinctive shells possess a low, open spiral structure, characterized by a row of respiratory pores along the outer edge.

Individual abalone species vary considerably in size, from a mere 20 mm up to an impressive 200 mm. The largest species, Haliotis rufescens, can reach an exceptional 300 mm (12 inches) in length. The thick inner layer of their ear-shaped shells, often called "ear shells," is composed of highly iridescent nacre, displaying a spectrum of strong, changeable colors that make each encounter unique.

Firmly attached to rocks with a broad, muscular foot, abalone are primarily stationary. These adult herbivores graze on macroalgae, showing a preference for red or brown varieties. A unique feature of their shell growth is the gradual sealing of older respiratory holes as new ones form, with each species maintaining a typical number of open holes, usually between four and ten.