Physical Description

  • Marine snail with one flat oval shell.
  • Shell is brown and ribbed, with 5 to 7 open respiratory pores elevated on edge of shell.
  • They are most famous for the inside of shell, which is an iridescent blue or green.
  • The head and tentacles are olive green, but the ruffle of tissue along the edge of the muscular “foot” is mottled cream and brown.
  • They reach lengths of 2.5 to 5 inches.

Range

  • Point Conception, California to Bahia de Magdalena, Mexico.

Habitat

  • Live in shallow water, from the low intertidal to depths of 60 feet.
  • Live on open or exposed coasts..
  • Often found in rock crevices and under rocks.

Reproduction

  • Green abalone have separate sexes and spawn from early summer to early fall.
  • They reach maturity at age 5-7.
  • They reproduce by broadcast spawning into the water, and as their numbers have gone down and males and females are further and further from each other, it can lead to reproductive failure.

Diet

  • Herbivores.
  • Mainly feed on drift algae, and prefer fleshy red algae.

Predators

  • Lobsters, crabs, octopuses.

Interesting Facts

  • These mollusks can live up to 30 years.
  • Commercial landings in California peaked in 1971 and have been declining ever since then. Green abalone are at risk of extinction, in part due to the fact that the males and females are often far from each other. The threats against them include illegal fishing, overharvesting, trade, disease, parasites, and warmer waters. 
  • Abalone are important to the kelp forest ecosystem because they compete for resources with sea urchins. If left unchecked, urchins can wipe out the kelp!

Sources: NOAA Fisheries; Orange County Coastkeeper

Photo: Michael Couffer

NOAA’s Southwest Fisheries Science Center here in La Jolla is researching abalone and how to help them recover.