The white abalone,

scientific name In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''Haliotis sorenseni'', is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of large

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Haliotidae, the abalone.Rosenberg, G. (2014). Haliotis sorenseni. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=445362 on 2014-10-29 The white abalone is an endangered species in the United States; it may now have the smallest population of all eight of the abalone species on the west coast of North America.

Distribution

Historically the white abalone ranged from Point Conception,

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, and was found especially on the offshore islands. In the most northerly part of the

range, white abalone were reported as being more common along the mainland coast. However, in the middle portion of the California range, they were noted to occur more frequently at the offshore islands, especially San Clemente and Santa Catalina Islands. At the more southerly end of the range, in Baja California, Mexico, white abalone were reported to occur more commonly along the mainland coast, but were also found at a number of islands including Isla Cedros and Isla Natividad. It remains unknown whether this distribution pattern was a result of lack of suitable habitat along the mainland coast in the mid portion of the range, or was instead due to overfishing in these more accessible mainland regions. Since the mid-1990s, extremely low numbers of isolated survivors have been identified along the mainland coast in Santa Barbara County and at some of the offshore islands and banks in the middle portion of the range, indicating the current range of white abalone in California may be similar to what it was historically. No recent information on current range is available for Baja California. The white abalone population in Mexico is thought to be depleted based on commercial fishery data, but the status of the species in Mexico remains largely unknown.

Description

Shell

The white abalone usually has between 3-5 open holes (respiratory pores) in its

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

. These holes collectively make up what is known as the selenizone which form as the shell grows. The shell is oval-shaped, very thin and deep. White abalone can grow to about , but are usually .

Anatomy

The epipodial tentacles are lacy, beige and yellow-green in color. The bottom of its foot is orange, and the epipodium (a sensory structure and extension of the foot that bears tentacles) is a mottled orange tan.

Ecology

Habitat

The white abalone is the deepest dwelling of eight species of California abalone, living at depths from . White abalone are found in open low and high relief rock or boulder habitat that is interspersed with sand channels. Sand channels may be important for the movement and concentration of drift macroalgae, and a variety of red

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

, upon which white abalone are known to feed.

Feeding habits

The white abalone is known to be a

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

, grazing mainly on macroalgae, such as '' Laminaria farlowii'' and '' Agarum fimbriatum'', and also several species of

red algae Red algae, or Rhodophyta (, ; ), make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest Phylum, phyla of algae, containing over 7,000 recognized species within over 900 Genus, genera amidst ongoing taxon ...

. Other species it eats include '' Chondracanthus exasperatus'', '' Laminaria farlowii'', '' Macrocystis pyrifera '', and '' Palmaria mollis''.

Life cycle

Like many gastropods, white abalone have a complex life cycle involving

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

l stages. Fertilized eggs hatch into larvae; these larvae eventually settle from the

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

to a hard substrate and metamorphose into the adult form. As a broadcast spawning gastropod, white abalone reproduce by releasing their eggs and

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

into the surrounding water. If fertilized, the eggs hatch after only one day, but sperm is required in order for an egg to be fertilized. Therefore, aggregations of adult male and female abalone are observed to improve fertilization. Haliotis sorenseni 2

Human use

Scripps Institution of Oceanography biologists conducted surveys of white abalone deep water habitat in the early 1970s, finding high concentrations of about one white abalone per square meter. Such densities were comparable to abundance of shallower species of abalone found in previously unfished or protected areas. Unfortunately, the high demand for the species led to a "boom-and-bust" fishery, which reduced the populations of this species in seven years. Considered a delicacy in California, white abalone, the rarest of the eight abalone species in the state, have declined due to poaching – the fishery was closed in 1996 – while at the same time, prices have escalated. Although white abalone were the first marine invertebrate on the United States Federal List of Endangered Species in 2001, the species could nevertheless become extinct unless extraordinary recovery measures are implemented. White abalone is being maricultured in order to produce young that can be placed back in the ocean, in hopes of bringing this species back to secure population levels before it becomes extinct. The White Abalone Restoration Consortium is a partnership with the Bodega Marine Laboratory niversity of California, Davis The Cultured Abalone Farm, the Santa Barbara Museum of Natural History Sea Center and the National Oceanic and Atmospheric Administration Southwest Fisheries Science Center on the Gaviota Coast which is studying the marine snail and restoring the wild populations. They are also collaborating in developing curriculum to educate the next generation about sustainable aquaculture and conservation.

References

;Sources *This article incorporates public domain text (a

public domain The public domain (PD) consists of all the creative work to which no Exclusive exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly Waiver, waived, or may be inapplicable. Because no one holds ...

work of the United States Government) from reference and CC-BY-2.5 text from reference Courchamp F., Angulo E., Rivalan P., Hall R. J., Signoret L., Bull L. & Meinard Y. (2006) "Rarity Value and Species Extinction: The Anthropogenic Allee Effect". ''PLoS Biology'' 4(12): e415.
Team Spawns Rare White Abalone

;Notes

External links

"Race To Save the White Abalone" video links
(NOAA Southwest Fisheries Science Center)
White Abalone Research
(NOAA Southwest Fisheries Science Center) * National Marine Fisheries Service. (October 2008). "White Abalone Recovery Plan (''Haliotis sorenseni'')". National Marine Fisheries Service, Long Beach, CA
PDF

Sonoma County Abalone Network
* {{Authority control sorenseni Endangered fauna of California Gastropods described in 1940 Biota of the Temperate Northern Pacific