Red Abalone (also known as Giant Abalone or Red Ear Shell)
Phylum: Mollusca, Class: Gastropoda, Order: Vetigastropoda, Family: Haliotidae, Genus: Haliotis, Species: Haliotis rufescens · Haliotidae (Abalone family) · Gastropod (univalve), whole shell, auriform or ear-shaped shape
Species
Haliotis rufescens
Shell Type
Gastropod (univalve), whole shell, auriform or ear-shaped shape
Family
Haliotidae (Abalone family)
Size
Approximately 4 inches in length, which is a medium-sized specimen. Adults typically range from 6 to 10 inches, with record specimens exceeding 12 inches.
Color & Pattern
The exterior features a brick-red to dark reddish-brown base color, often mottled with weathering, fine growth lines, and camouflage patterns of greenish-grey and brown algae buildup. The interior exhibits brilliant mother-of-pearl (nacre) with iridescent flashes of pink, green, silver, and blue.
Rarity
Uncommon to Rare for a whole, well-preserved specimen depending on strict local regulations, marine protections, and heavy recreational/commercial harvesting restrictions.
Habitat
Found in shallow marine waters, typically from the intertidal zone down to depths of about 60 feet (20 meters), inhabiting rocky reefs and kelp forests where they cling tightly to rocks using their powerful muscular foot.
Geographic Range
Northeast Pacific Ocean along the western coast of North America, ranging from British Columbia, Canada, down to Baja California, Mexico, with greatest abundance along the central and northern coast of California.
Description
A magnificent and robust ear-shaped univalve shell with a low, broad profile. The outer surface is sculpted with rough, undulating growth lines and a brick-red exterior, perforated by a distinct series of open respiratory pores along a raised ridge. The interior is lined with a thick, glowing layer of iridescent nacre that shimmers with a rainbow of colors.
Key Features
Distinguished by its large size, brick-red exterior coloration, ear-like (auriform) shape, and typically 3 to 4 open, slightly elevated respiratory holes (tremata) remaining open at any given time along the shell's margin.
Collector Value
Highly sought after by shell collectors and artisans worldwide for its stunning iridescent interior nacre. Prices vary widely based on size, polish state, and locality, ranging from moderately priced tourist specimens to highly prized, large regulated collector pieces.
Condition Notes
Good condition. The shell is intact with visible respiratory pores and a relatively preserved outer surface showing natural growth patterns and mild environmental weathering. Collector grade: Good to Fine.
Interesting Facts
Abalones are famous for their incredibly strong nacre (mother-of-pearl), which has a unique brick-and-mortar micro-structure that inspires modern high-impact ceramic engineering. They feed primarily on giant kelp using a ribbon-like tongue called a radula.
Ecological Role
Abalones play a vital role as herbivorous grazers in kelp forest ecosystems, helping to control algae populations. They are a primary food source for sea otters, large fish, and octopuses, and are heavily managed and protected under strict conservation laws due to historical overfishing.
Similar Species
Black Abalone (Haliotis cracherodii) which is darker and smoother with more pores, and Green Abalone (Haliotis fulgens) which features a more fluted shell margin and bright emerald-green internal nacre.
Beach Finding Tips
Finding a whole, undamaged abalone shell while beachcombing is quite difficult due to their strong grip on rocks and vulnerability to wave action. They are most commonly encountered by divers or beachcombers after major coastal storms in rocky Northern California or Pacific Northwest areas.