Red Abalone

Haliotis rufescens

Red Abalone

Haliotis rufescens

Rocky Coast

At the Aquarium

Rocky Coast

Appearance

Has a thick and rough-surfaced shell that is pink or red and usually has 3 or 4 respiratory pores, which are slightly raised and oval-shaped open holes on the left side. They have a black mantle and black sensory tentacles; the underside of the foot is yellow.

Habitat

Bays and low intertidal and subtidally to depths of 98 feet in rocky habitats and kelp forests.

Diet

Herbivore: primarily eats kelp

Life History

Red abalone reproduce by broadcast spawning. In order for fertilization to take place, there needs to be enough density of spawning abalone, with individuals no more than 5 feet apart. Sperm or eggs are released through the respiratory pores. Larvae have a short planktonic phase that lasts hours to a few days before they start seeking out a settling site abundant with coralline red algae, which is one of their first foods. The shell begins growing in the larval stage and will continue growing throughout the abalone’s life.

The red abalone is the largest and longest-lived abalone species. They can reach lengths of 12.3 inches and live for up to 40 years.

IUCN Status

Critically Endangered

Ecosystem & Cultural Importance

Humans have been using red abalone as a food source since prehistoric times. Shells have been recovered from 11,500-12,000 year old archaeological sites in the Channel Islands. Red Abalone were a dietary staple of native people along the California coast for centuries. A small red abalone recreational fishery in Oregon closed in 2017 and a larger recreational fishery in California south of San Francisco closed in 2018, due to steep declines in red abalone numbers, in large part due to loss of kelp forests. There is now an aquaculture industry for red abalone.

They are important to kelp forests because they eat coralline algae, providing space for other organisms to settle. They also provide a home to a type of hooded shrimp Betaeus harfordi that is only found on abalones.

Sea otters are a major predator of red abalone. They are also eaten by cabezon, kelp greenling, bat rays, octopuses, California spiny lobsters, giant spined sea stars and sunflower stars.

Central Oregon to Baja California, Mexico

Red abalone do sometimes occur in the low intertidal so you might be lucky enough to see one while tidepooling.

An abalone breathes by drawing in water under the edge of its shell; this flows over its gills and then out through the respiratory pores. Waste, sperm or eggs also exit through these pores.

Older and larger females release many more eggs than smaller, younger females. A newly sexually mature female might broadcast a few thousand eggs while a larger, older female will lay up to 6 million eggs.

Red Abalone

Red Abalone

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

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