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The black abalone, Haliotis cracherodii, is a species
Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
 of large edible sea snail
Snail

The word snail is a common name for almost all members of the molluscan class Gastropoda that have coiled animal shells in the adult stage. When the word snail is used in a general sense, it includes sea snails, land snails and freshwater snails....
, a marine
Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology....
 gastropod mollusk in the family Haliotidae, the abalones.

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
North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
, but now, because of overfishing
Overfishing

Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
 and the Withering Syndrome
Withering Abalone Syndrome

Withering abalone syndrome is a disease of the abalone shellfish, primarily found in the black abalone and red abalone species.First described in 1986, it is caused by the bacterium "Candidatus Xenohaliotis californiensis", which attacks the lining of the abalone's digestive tract, inhibiting the production of digestive enzymes....
, it has much declined in population.

k abalones can be found along the Pacific coast of the USA from Mendocino County, California
Mendocino County, California

Mendocino County is a county located on the north coast of the U.S. state of California, north of the greater San Francisco Bay Area and west of the California Central Valley....
 to Cabo San Lucas
Cabo San Lucas

Cabo San Lucas is a city at the southern tip of the Baja California peninsula at , in the municipality of Los Cabos in the states of Mexico of Baja California Sur, Mexico....
, Baja California
Baja California

Baja California is the northernmost States of Mexico of Mexico. Before becoming a state in 1953, the area was known as the North Territory of Baja California....
, Mexico
Mexico

The United Mexican States , commonly known as Mexico , is a federalism constitutionalism republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico....
.

Prehistoric distribution has been confirmed along much of this range from archaelogical recovery at a variety of Pacific
Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Mare Pacificum, "peaceful sea", bestowed upon it by the Portugal explorer Ferdinand Magellan....
 coast
Coast

The coast is defined as that part of the land adjoining or near the ocean or its saltwater arms. A precise line that can be called a coastline cannot be determined due to the process of tides....
al Native American
Indigenous peoples of the Americas

The indigenous peoples of the Americas are the pre-Columbian inhabitants of the Americas, their descendants, and many ethnic groups who identify with those peoples....
 sites.






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The black abalone, Haliotis cracherodii, is a species
Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
 of large edible sea snail
Snail

The word snail is a common name for almost all members of the molluscan class Gastropoda that have coiled animal shells in the adult stage. When the word snail is used in a general sense, it includes sea snails, land snails and freshwater snails....
, a marine
Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology....
 gastropod mollusk in the family Haliotidae, the abalones.

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
North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
, but now, because of overfishing
Overfishing

Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
 and the Withering Syndrome
Withering Abalone Syndrome

Withering abalone syndrome is a disease of the abalone shellfish, primarily found in the black abalone and red abalone species.First described in 1986, it is caused by the bacterium "Candidatus Xenohaliotis californiensis", which attacks the lining of the abalone's digestive tract, inhibiting the production of digestive enzymes....
, it has much declined in population.

Range of distribution

Black abalones can be found along the Pacific coast of the USA from Mendocino County, California
Mendocino County, California

Mendocino County is a county located on the north coast of the U.S. state of California, north of the greater San Francisco Bay Area and west of the California Central Valley....
 to Cabo San Lucas
Cabo San Lucas

Cabo San Lucas is a city at the southern tip of the Baja California peninsula at , in the municipality of Los Cabos in the states of Mexico of Baja California Sur, Mexico....
, Baja California
Baja California

Baja California is the northernmost States of Mexico of Mexico. Before becoming a state in 1953, the area was known as the North Territory of Baja California....
, Mexico
Mexico

The United Mexican States , commonly known as Mexico , is a federalism constitutionalism republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico....
.

Prehistoric distribution has been confirmed along much of this range from archaelogical recovery at a variety of Pacific
Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Mare Pacificum, "peaceful sea", bestowed upon it by the Portugal explorer Ferdinand Magellan....
 coast
Coast

The coast is defined as that part of the land adjoining or near the ocean or its saltwater arms. A precise line that can be called a coastline cannot be determined due to the process of tides....
al Native American
Indigenous peoples of the Americas

The indigenous peoples of the Americas are the pre-Columbian inhabitants of the Americas, their descendants, and many ethnic groups who identify with those peoples....
 sites. For example, Chumash
Chumash

The Chumash are Native Americans in the United States people who historically inhabit chiefly central and southern coastal regions of California, in portions of what is now San Luis Obispo, Santa Barbara, California, Ventura, California and Los Angeles counties, extending from Morro Bay in the north to Malibu, California in the south....
 peoples in central California were known to have been harvesting black abalone approximately a millennium earlier in the Morro Bay area.

There is a subspecies
Subspecies

In biology, subspecies is the taxonomic rank immediately subordinate to a species. A subspecies is a taxonomic group which is less distinct than the Common descent or species from which it originates....
: Haliotis cracherodii californiensis, which is found around Guadalupe Island
Guadalupe Island

Guadalupe Island, or Isla Guadalupe is a volcanic island located 241 kilometers off the west coast of Mexico's Baja California Peninsula and some 400 kilometers southwest of the city of Ensenada in Baja California state, in the Pacific Ocean....
, off Baja California
Baja California

Baja California is the northernmost States of Mexico of Mexico. Before becoming a state in 1953, the area was known as the North Territory of Baja California....
 (Mexico
Mexico

The United Mexican States , commonly known as Mexico , is a federalism constitutionalism republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico....
).

Shell description

The exterior of the shell is smoother than most abalones. The coloration is dark brown, dark green, dark blue or almost black. The interior of the shell shows a pale pinkish and greenish iridescence
Iridescence

Iridescence is an optical phenomenon in which hue changes with the angle from which a surface is viewed. Iridescence may be easily seen in soap bubbles and butterfly wings....
. There are usually five to seven open respiratory holes in the shell and the rims of the holes are flush with the rest of the shell.

The black abalone's shell length can reach a maximum of 20 cm.

Soft parts

In the living animal, the tentacles on the epipodium, the mantle, and the foot are black.

Habitat

Black abalones 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
Tide

Tides are the rising of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans. Tides cause changes in the depth of the marine and estuary water bodies and produce oscillating currents known as tidal streams, making prediction of tides important for coastal navigation ....
. They generally occur in areas of moderate to high surf. They are herbivores, feeding on kelp
Kelp

Kelp are large seaweed plants , belonging to the brown algae and classified in the order Laminariales. There are about 30 different genus. Some species can be very long and form kelp forests....
 and drifiting algae
Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds....
.

History of Human Use

Humans have harvested black abalones along the California Coast for at least 10,000 years. On San Miguel Island, archaeological evidence shows that the Island Chumash people and their ancestors ate black abalone for millennia and also used the shells to make fishhooks, beads, and ornaments. After the Chumash and other California Indians were devastated by European diseases, and sea otters were nearly eradicated from California waters by the historic fur trade, black abalone populations rebounded and attracted an intensive intertidal fishery conducted primarily by Chinese immigrants from the 1850s to about 1900.

Predators

Predators of this species other than mankind are sea otter
Sea Otter

The sea otter is a marine mammal native to the coasts of the northern and eastern Pacific Ocean. Adult sea otters typically weigh between 14 and 45 Kilogram , making them the heaviest members of the Mustelidae, but among the smallest marine mammals....
s, starfish, large fish
Fish

A fish is any marine biology vertebrate animal that is typically ectothermic , covered with scale , and equipped with two sets of paired fins and several unpaired fins....
es and octopus
Octopus

The octopus is a cephalopod of the order Octopoda that inhabits many diverse regions of the ocean, especially coral reefs. The term may also refer to only those creatures in the genus Octopus ....
es.

Diseases

Beginning in 1985, black abalones in southern California were experiencing mass mortality due to a bacterial disease known as Withering Syndrome
Withering Abalone Syndrome

Withering abalone syndrome is a disease of the abalone shellfish, primarily found in the black abalone and red abalone species.First described in 1986, it is caused by the bacterium "Candidatus Xenohaliotis californiensis", which attacks the lining of the abalone's digestive tract, inhibiting the production of digestive enzymes....
 or abalone wasting disease. This has led to local extinction of black abalone along the California coast and contributed to the closure of commercial and sport abalone fisheries in California
California

California is a U.S. state on the West Coast of the United States of the United States, along the Pacific Ocean. It is bordered by Oregon to the north, Nevada to the east, Arizona to the southeast, and to the south the Mexico state of Baja California....
 in 1993.

The disease is lethal and affects all sizes of abalone. It causes lethargy, retracted visceral tissues, and atrophy of the foot muscle which interferes with its ability to adhere to substrate. Elevated water temperatures accelerate the spread of the disease, decreasing survival.

Life History

Black abalone reach sexual maturity at 3 years and can live 30 years or more (California Department of Fish and Game 2001, National Marine Fisheries Service 2007). Spawning occurs in spring and early summer; occasionally, a second spawn occurs in the fall (California Department of Fish and Game 2001). Black abalone are broadcast spawners, and successful spawning requires that individuals be grouped closely together. Larvae are free-swimming for between 5 and 14 days before they settle onto hard substrate, usually near larger individuals (California Department of Fish and Game 2001). Juveniles do not tend to disperse great distances, and current populations of black abalone are generally composed of individuals that were spawned locally. Juveniles settle in crevices and remain hidden until they reach approximately 4 inches in length. At that point, adults congregate in more exposed areas such as rocks and in tide pools (California Department of Fish and Game 2001).

Conservation Status

Black abalone are as Critically Endangered. On June 23, 1999, the U.S. (NMFS) designated the black abalone as a candidate for protection under the Endangered Species Act (64 FR 33466). On December 21, 2006, the submitted a to NMFS to list the black abalone. On January 11, 2008, NMFS completed their of the species and proposed that it be listed as endangered (). Black abalone were listed as endangered on January 14, 2009 (). No critical habitat has been designated, and no recovery plan has been developed. However, the State of California has a to guide conservation efforts.

Factors of Decline

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 (California Department of Fish and Game 2001). Black abalone were the last to be targeted, with the peak harvest occurring in the 1970s. Additionally, improved harvesting technologies that expanded the harvesting areas and supported larger harvests per unit effort were not initiated (California Department of Fish and Game 2001). Even though harvesting black abalone is currently illegal in California, poaching still occurs.

The depleted stocks of black abalone were further reduced by withering syndrome, first discovered in 1985 in some of the last large colonies of black abalone in the Channel Islands (California Department of Fish and Game 2001, National Marine Fisheries Service 2007). The disease impairs the production of digestive enzymes, effectively starving the abalone to death. Following onset of symptoms, the animal usually quickly dies. In many locations, greater than 90% of individuals have been lost, and in some places, a total loss of the black abalone population occurred. The disease spread from the Channel Islands to the mainland coast in 1992, where it devastated most populations in warmer waters south of Point Conception or in locally warmer waters further north (National Marine Fisheries Service 2007).

Line notes


External links