Haliotis cracherodii

Haliotis cracherodii, the black abalone, is a species of large edible sea snail, a marine gastropod mollusk in the family Haliotidae, the abalone.

This species is relatively small compared with most of the other abalone species from the eastern Pacific, and it has a relatively smooth dark shell.

This used to be the most abundant large marine mollusk on the west coast of North America, but now, because of overfishing and the withering syndrome, it has much declined in population and the IUCN Red List has classed the black abalone as Critically Endangered.

Taxonomy

Haliotis cracherodii comprises two subspecies:

Haliotis cracherodii californiensis Swainson, 1822 (synonyms: Haliotis bonita Orcutt, 1900; Haliotis californiensis Swainson, 1822)
Haliotis cracherodii cracherodii Leach, 1814 (synonyms: Haliotis expansa Talmadge, 1957; Haliotis holzneri Hemphil, 1907; Haliotis imperforata Dall, 1919; Haliotis lusus Finlay, 1927; Haliotis rosea Orcutt, 1900; Haliotis splendidula Williamson, 1893)

Description

thumb|left|Dorsal view of a [[gastropod shell|shell of Haliotis cracherodii]]

The coloration is dark brown, dark green, dark blue or almost black. The silvery interior of the shell shows a pale pinkish and greenish iridescence. The exterior of the shell is smoother than most abalone, or may have low obsolete coarse spiral lirae and lines of growth. The shell is oval, evenly convex, the two sides equally curved. The back of the shell is regularly convex, with little algal growth. The interior of the shell is pearly with pink and green iridescence.

Prehistoric distribution has been confirmed along much of this range from archaeological recovery at a variety of Pacific coastal Native American sites. For example, Chumash peoples in central California were known to have been harvesting black abalone approximately a millennium earlier in the Morro Bay area.

The subspecies Haliotis cracherodii californiensis is found around Guadalupe Island, off Baja California (Mexico).

Ecology

Habitat

thumb|left|Two black abalone shells in a tide pool at low tide

Black abalone cling to rocky surfaces in the low intertidal zone, up to 6 m deep. They can typically be found wedged into crevices, cracks, and holes during low tide. They generally occur in areas of moderate to high surf.

Life cycle

thumb|Life cycle of Haliotis cracherodii

Black abalone reach sexual maturity at 3 years and can live 30 years or more. Spawning occurs in spring and early summer; occasionally, a second spawn occurs in the fall. Competition for space with other species (such as the sea urchins Strongylocentrotus purpuratus and Strongylocentrotus franciscanus) is also frequent. On December 21, 2006, the Center for Biological Diversity submitted a petition to NMFS to list the black abalone. On January 11, 2008, NMFS completed their status review of the species and proposed that it be listed as endangered. Black abalone were listed as endangered on January 14, 2009. The NMFS designated critical habitat for the endangered black abalone on October 27, 2011. The state of California has introduced an Abalone Recovery Management Plan to guide conservation efforts.

Black abalone have dramatically declined in numbers throughout their historical range, and are locally extirpated in certain areas. This decline was initiated by overfishing. Following World War II, the California abalone fishery was not managed for individual species. Therefore, it resulted in a systematic depletion of various abalone species as the fishery over-harvested one species and then moved on to the next in an attempt to meet demand.

References

External links

Gastropods.com: Haliotis (Haliotis) cracherodii
Withering Syndrome in Black Abalone