Overview

Brief Summary

Biology

This sessile mollusc uses its foot to clamp tightly to a rock, where it feeds on algal matter scraped from the rock surface, and catches drifting algae with its tentacles. Juveniles tend to reside in crevices to reduce their risk of predation, but the larger adults will move out onto rock surfaces. They may still be preyed upon by fish and otters (1). Between three and seven years old, the black abalone will begin to reproduce. In a perfectly synchronised release of eggs and sperm amongst all the abalones in one area, fertilisation occurs, resulting in tiny free-swimming larvae. After 15 days, the larvae metamorphose into their adult form, develop a shell and settle onto a rock. They are thought to be able to live for between 25 and 75 years, and will begin to reproduce between three and seven years (1).
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Description

The exterior of this marine gastropod mollusc's shell varies in colour from dark blue through dark green to black (2). It is smooth with little algal growth, and has five to nine open pores in a line along the left side of the shell. The rear of the shell is spiralled, and the mantle, foot and tentacles are black (3). The interior of the shell is pearly with pink and green iridescence (2).
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Distribution

occurs (regularly, as a native taxon) in multiple nations

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National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) There is some debate as to the northern historic range extent of this species. Many have cited the historic range as extending from Coos Bay, Oregon to Cabo San Lucas, Southern Baja California, Mexico but the northernmost documented record from museum specimens is from Crescent City, Del Norte Co., California. The current range extends from Point Arena (Mendocino Co., California, south to Northern Baja California, Mexico (USFWS, 2008).

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Range Description

The black abalone, Haliotis cracherodii, is found in intertidal waters off California, USA, and Baja California, Mexico.
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Range

The black abalone is found on the coasts of Baja California, Mexico and California, USA (1).
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Ecology

Habitat

Habitat Type: Marine

Comments: The species occurs from the high intertidal to 6 m depth, and has evolved to withstand extreme variation in environmental conditions such as temperature, salinity, moisture, and wave action. It occurs on a variety of rock types and complex surfaces with cracks and crevices are crucial to recruitment (USFWS, 2008).

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Habitat and Ecology

Habitat and Ecology
H. cracherodii is a sessile marine gastropod. It clamps tightly to rocky substrates and feeds on algal matter scraped from the rock surface. Gametes are released into the water where fertilization occurs to produce free-swimming larvae. Successful fertilization requires aggregated adults and synchronized gonad development and release (McShane 1996). After approximately 15 days as non-feeding zooplankton, the larvae metamorphose into their adult form, develop a shell, and settle onto a hard substrate (Douros 1985). Juveniles mainly reside in rocky crevices and feed primarily on benthic diatoms, bacterial films and algae found on coralline algal substrate (NMFS 2000). As juveniles, abalone are vulnerable to predators which graze the surfaces of coralline algae and associated species (McShane 1989). As they increase in size they become less vulnerable to predation and are able to emerge from their sheltered habitat and search out more desirable food sources (NMFS 2000). Adult abalone depend primarily on drift algae (Tegner and Dayton 1987). Main predators of adult abalone are fishes, otters and humans.

Most black abalone are found in the intertidal zone, ranging from the high tide line to a depth of up to five meters (Lindberg 1989).

Generation time is not easy to determine. Individuals do not display the same growth rate and older individuals may cease to grow altogether (B. Tissot, Washington University, pers comm.). Reproductive maturity is reached between three and seven years (when They are re approximately 130-150 mm in length), but life expectancy ranges from 25 to 75 years. Taking an average of these provides only a very rough estimate for the average age of parents, especially since the relationship between age and fecundity is unknown. Nonetheless, generation time is estimated to be between 14 and 41 years, thus a minimum three generation period would be 42 years (Smith et al. 2001).

Systems
  • Marine
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Inhabits rocky substrates in intertidal waters, from the high tide line to a depth of 5 m (1).
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Migration

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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Population Biology

Number of Occurrences

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 - 300

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Molecular Biology and Genetics

Molecular Biology

Barcode data: Haliotis cracherodii

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 39 barcode sequences available from BOLD and GenBank.

Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.

See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

ATTGCGGTACCAACTGGAATCAAGATTTTTAGTTGGCTT---GCCACAATCCACGGTGCC---CGAATAAAATATGAAGCCTCAATACTATGGGCCCTCGGGTTCATTTTCCTATTTACAGTTGGGGGGCTAACTGGGATCGTCTTATCAAACTCATCCTTAGATATCATGCTGCACGACACATACTACGTAGTAGCCCATTTCCACTACGTC---CTATCAATAGGAGCTGTGTTTGCCCTGTTTGCTGCTTTCTACCACTGATACCCTTTATTTACTGGGCTTACTCTACACGCCCGATGAACGAAAGCACACTTCTTCATTATGTTTATCGGAGTTAATGTAACATTCTTTCCTCAGCATTTCTTAGGACTAGCTGGAATGCCTCGT---CGGTACTCTGACTACCCCGACTCCTATACC---AAATGAAATGTTGTATCCTCATTCGGATCTATAATCTCTCTAGTCGCCGTCCTTTACTTCATAGTAATTGTATGGGAATCTTTAGTCTCGCAACGAGGGGTC---CTTTGGGCTCTAAACATGTCTACCAGA
-- end --

Download FASTA File

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Statistics of barcoding coverage: Haliotis cracherodii

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 7
Specimens with Barcodes: 7
Species With Barcodes: 1
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Conservation

Conservation Status

National NatureServe Conservation Status

United States

Rounded National Status Rank: N3 - Vulnerable

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NatureServe Conservation Status

Rounded Global Status Rank: G3 - Vulnerable

Reasons: The current range extends from Point Arena (Mendocino Co., California, south to Northern Baja California, Mexico. This species occurs over a broad latitudinal range, tough the range appears to have narrowed somewhat from historic times. Historic fishing pressure and current loss to to disease and poor viability threatend this species with extinction.

Intrinsic Vulnerability: Highly vulnerable

Comments: Studies indicate minimal gene flow among populations, populations are composed predominantly of closely related indivduals produced by local spawning events, gene flow among island populations is relatively greater than between island and mainland populations, and overall connectivity among black abalone populations is low and likely reflectes limited larval dispersal and a low degree of exchange among populations. Natural recovery of severely reduced populations can be a very slow process due to low reproductive efficiency of widely dispersed adult populations coupled with short larval dispersal distances (USFWS, 2008).

Environmental Specificity: Moderate. Generalist or community with some key requirements scarce.

Comments: The species occurs from the high intertidal to 6 m depth, and has evolved to withstand extreme variation in environmental conditions such as temperature, salinity, moisture, and wave action. It occurs on a variety of rock types and complex surfaces with cracks and crevices are crucial to recruitment (USFWS, 2008).

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IUCN Red List Assessment


Red List Category
CR
Critically Endangered

Red List Criteria
A4e

Version
3.1

Year Assessed
2003

Assessor/s
Smith, G., Stamm, C. & Petrovic, F. (McGill University)

Reviewer/s
Seddon, M.B., Mikkelsen, P., Roth, B. (Mollusc RLA), Haaker, P., Geiger, D. & Scott, P.

Contributor/s

Justification
H. cracherodii began supporting a commercial fishery in California in 1968. In the mid 1980s a wasting disease, Withering Syndrome, began to appear, reducing the commercial catch considerably. At present, the harvest of black abalone is illegal in California, but the species is still harvested commercially in Mexico. At most surveyed locations where the disease was present, black abalone populations were reduced by more than 80%. Fishers on the southern shore of Santa Cruz Island made the first observation of this disease in 1985. It has since spread throughout all the California Channel Islands and northwards to Monterey. In Mexico, cases of Withering Syndrome have been reported as far south as Cedros Island in Baja California. The spread of the disease now extends over almost the entire range of the species. Withering Syndrome does not appear to showing any signs of relenting in its progression along the coast in either direction. The strong correlation between adult abundance and recruitment suggests that larvae do not disperse very far from their point of origin, thus depleted abalone populations are unlikely to be restored by recruitment from distant populations. If no action is taken, it is estimated that H. cracherodii will decline by at least 80% over a period of three generations (from approximately 1975 to 2015), extending into the past and the future, and consequently, the species qualifies for Critically Endangered under criterion A4.
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Current Listing Status Summary

Status: Endangered
Date Listed: 04/13/2011
Lead Region:   National Marine Fisheries Service (Region 11) 
Where Listed:


For most current information and documents related to the conservation status and management of Haliotis cracherodii, see its USFWS Species Profile

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Status

The black abalone is classified as Critically Endangered (CR A4e) on the IUCN Red List 2004 (1).
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Global Short Term Trend: Decline of 70 to >90%

Comments: Both commercial fishery trends and long-term monitoring studies indicate significant declines in abundance began in southern California in the mid-1980s and noted declines were observed in Baja California, Mexico, in the late 1980s and 1990s. Severe declines in abundance (greater than 90%) have occurred at the majority (76%) of long-term monitoring study sites, including all sites in southern California (USFWS, 2008).

Global Long Term Trend: Decline of >90%

Comments: This species occurs over a broad latitudinal range, tough the range appears to have narrowed somewhat from historic times; ppulations have been severely reduced over an area that covers more than half of the species' geographic range These declines have been particularly severe in the southern California Islands; areas that hisorically comprised greater than 90% of the commerical fishery catch and the majority of the adult black abalone populations in California. The species has experienced major declines in abundance that prompted eventual closure of the commercial and recreational fisheries and resulted in local extinctions and low local densities in the majority of long-term monitoring studies in California (USFWS, 2008).

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Population

Population
Large-scale commercial fishery of black abalone began in California in 1968 (Haaker et al. 1995). Like most other abalone fisheries, black abalone landings underwent a rapid rise, peaking in 1973 at a maximum catch of over 800 metric tonnes, followed by a decline (Parker et al. 1992). In 1992, commercial landings had diminished to 17.4 metric tonnes, as a wasting disease, Withering Syndrome (WS) spread throughout southern California (Haaker et al. 1992, Haaker et al. 1995).

Population Trend
Decreasing
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Threats

Degree of Threat: Very high - high

Comments: Documented threates include (from greatest to least, though all are high): the disease known as withering syndrome that has spread to areas throughout the range of the species and has been responsible for local extirpation of populations throughout a large part of the species' range, low adult densities below the critical threshold density required for successful fertilization, other interacting factors (suboptimal water temperatures negatively impacted by global warming, reduced genetic diversity, illegal harvest). Legal harvest played a significant role as a threat to the species in the past as Rogers and Bennett et al. (2002) estimated that the California abalone fisheries amy have contributed up to 99% of the reduction in black abalone abundance in the United States; however the fisheries were closed in 1993

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Major Threats
Withering Syndrome (WS) is the main threat to black abalone. It is manifested by epipodial discoloration, loss of appetite, severe weight loss and atrophy of the foot muscle. As a consequence, abalone lose their ability to adhere to the substratum and eventually die (Tissot 1991, Haaker et al. 1992). The first reports of WS were in black abalone were made by fishers on the southern shore of Santa Cruz Island (Lafferty and Kuris 1993). The disease then spread throughout all the Californian Channel Islands from 1985 to 1992, except Santa Catalina Island, where no studies have been conducted (Haaker et al. 1992, Lafferty and Kuris 1993, Van Blaricom et al. 1993). At most surveyed locations black abalone were initially reduced to less than 20% of their initial densities (Tissot 1990, Davis et al. 1992, Richards and Davis 1993, Altstatt et al. 1996). Some have completely lost their black abalone populations (P. Hakker pers. comm.).

Black abalone are also affected by the large human population inhabiting southern California, the majority of which reside within 50 km of the coast (Parker et al. 1992). Coastal development, such as residential areas, harbours and coastal access points and large ocean discharges of municipal and industrial wastes contribute to the degradation and loss of near shore habitat (Parker et al. 1992). Commercial and recreational fishing have also placed black abalone populations under intense pressure. The large decline in fisheries landings may have been a consequence of over harvesting (Parker et al. 1992), however the mass mortality of populations in the Channel Islands that began in 1985 has been attributed to WS and continued fishing (Haaker et al. 1992).

Other possible threats to the species include storm, competition with other marine organisms and predation (Smith et al. 2001).
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The black abalone has suffered a serious decline since 1985 due to a disease known as withering syndrome, which spread through the California Channel Islands between 1985 and 1992. It causes wasting of the foot muscle, preventing the abalone from properly adhering to a rock, causing the abalone to become discoloured, lose weight and die. Population losses in each area ranged from 20% to total (1). Other threats include coastal development for residential areas, harbours and waste discharges, compounded by commercial and recreational fishing of the black abalone (1).
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Management

Global Protection: Several (4-12) occurrences appropriately protected and managed

Comments: Fishing is banned n the U.S. since 1993 and critical habitat designation is being considered. The species is also on th eNMFS Species of Concern list. Three coastal national marine sanctuaries in California contain intertidal habitat suitable for the species (Channel Islands National Marine Sanctuary, Monterey Bay National Marine Sanctuary, Gulf of the Farallones National Marine Sanctuary) but these offer little protection to the threat of withering syndrome (UFSWS, 2008). The U.S. federal government has proposed declaring the species federally endangered; a decision is expected in 2009.

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Conservation Actions

Conservation Actions
All abalone fisheries in California are managed by the California Department of Fish and Game. The restrictions employed can range from minimum legal size limits and bag limits to harvest seasons and closures (Breen 1989, P. Haaker pers. comm.). The harvest of black abalone is currently illegal in California.

In Mexico, green abalone, H. fulgens and pink abalone H. corugata are the main focus of commercial fishery. Black abalone do not form a large proportion of total abalone landings. Exclusive rights to abalone exploitation were granted to cooperative fishers' organizations. Although new legislation in 1992 allowed for the entry of the private sector into the fishery, all abalone harvesting is still done by cooperatives (Ramande-Villanueva et al. 1998). Total allowable catches per cooperative (TACCs) were introduced in 1973, but their criteria have changed appreciably over the years (Ramande-Villanueva et al. 1998). Since black abalone make up such a small proportion of the commercial catch in Mexico, it is difficult to assess the impact of these regulations on the species.

In January 1999 the National Marine Fisheries Service (NMFS) published its updated list of candidate species under the Endangered Species Act (ESA). Black abalone was one of 14 new species added to the list (NMFS 1999). The NMFS intends to conduct a review to determine whether black abalone deserves a national listing of endangered or threatened (P. Haaker, pers. comm.). Listing as a candidate species does not, however, provide substantive or procedural protection for the species under the ESA (NMFS 1999).

Stock restoration by transplantation from distant populations has been proposed to restore depleted populations (Tissot 1997). Smith et al. (2001) propose that both American and Mexican fishery authorities work together to develop a re-stocking program to help restore black abalone populations all along the coast, especially in key locations such as the Channel Islands. Since the greatest threat facing the black abalone is disease, special precaution must be taken to ensure that the transplantation of adult abalone does not create a new path for the spread of WS.

While not an especially charismatic species, many living in coastal California and Baja California recognize that the black abalone is important to local economies. A well designed public education campaign may result in a successful appeal for public funding (Smith et al. 2001).

There is a need to survey areas where the status of black abalone populations are currently unknown, namely the coastline between Los Angeles and central Baja California, in addition to new surveys being carried out at sites previously examined. A study of withered black abalone at the northern fringe of WS's current range (Monterey and San Francisco) (Smith et al. 2001).

Perhaps most importantly, further investigation of WS itself is also needed (Smith et al. 2001), including investigation into whether WS is caused by an introduced pathogen, identification of other species that may serve as reservoir hosts, and identification of resistant individuals for potential brood stock and development of husbandry.
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Conservation

All abalone fisheries in California are managed by the California Department of Fish and Game, which restricts the size of abalones caught, and the season in which harvesting can take place. In Mexico, there is a total allowable catch limit for black abalones. The black abalone is a candidate species on the US Endangered Species Act, and whilst this could be beneficial in the future, it does not currently give the species any legal protection (1). An American-Mexican fishery authority alliance has been proposed as a means to develop a restocking programme to restore black abalone populations. There is to be a public appeal for funding, which would allow an investigation into the causes of withering syndrome (1).
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Wikipedia

Black abalone

The black abalone, Haliotis cracherodii, is a species of large edible sea snail, a marine gastropod mollusk in the family Haliotidae, the abalones.[2]

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.

Taxonomy[edit]

Haliotis cracherodii comprises two subspecies:[1]

  • 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[edit]

Dorsal view of a shell of Haliotis cracherodii

The coloration is dark brown, dark green, dark blue or almost black.[3] The silvery interior of the shell shows a pale pinkish and greenish iridescence. The exterior of the shell is smoother than most abalones, 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.[3] The shell is not carinated at the row of holes. The spire is near the margin. The cavity of the spire is minute, concealed or nearly so. The muscle scar is generally not distinct. There are usually five to seven small, open respiratory holes, or pores, along the left side of the shell[3] and the rims of the holes are flush with the rest of the shell. These holes collectively make up what is known as the selenizone which form as the shell grows. The columellar plate is not truncate below, sloping inward, its face concave. The rear of the shell is spiralled, and the mantle, foot and tentacles are black.[4] The interior of the shell is pearly with pink and green iridescence.[3]

The black abalone's shell length can reach a maximum of 20 cm, being typically 10–14 cm long.[5]

In the living animal, the tentacles on the epipodium, the mantle, and the foot are black.[5]

Distribution[edit]

Black abalones can be found along the Pacific coast of the USA from Mendocino County, California to Cabo San Lucas, Baja California, Mexico.[6]

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.[7]

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

Ecology[edit]

Habitat[edit]

Two black abalone shells in a tide pool at low tide

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. They generally occur in areas of moderate to high surf.[5] Juveniles tend to reside in crevices to reduce their risk of predation, but the larger adults will move out onto rock surfaces.[8]

Life cycle[edit]

Life cycle of Haliotis cracherodii

Black abalone reach sexual maturity at 3 years and can live 30 years or more.[5][9] Spawning occurs in spring and early summer; occasionally, a second spawn occurs in the fall.[9] 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,[9] where they then metamorphose into their adult form, develop a shell and settle onto a rock.[8] 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.[9] They are thought to be able to live for between 25 and 75 years, and will begin to reproduce between three and seven years.[8]

Feeding habits[edit]

Black abalones are herbivorous gastropods, and feed mostly on drift algae and kelp. Their primary food species depend on the habitat. In southern California habitats, black abalones are thought to feed on the giant kelp (Macrocystis pyrifera) and feather boa kelp (Egregia menziesii), while in central and northern California habitats they feed on the bull kelp (Nereocystis leutkeana).[5]

Interspecific relationships[edit]

Predators of this species other than mankind are sea otters (such as the southern sea otter, Enhydra lutris), fish (such as the California sheephead, Semicossyphus pulcher) and invertebrates, including crustaceans such as the striped shore crab, Pachygrapsus crassipes, and spiny lobsters.[5][10] Competition for space with other species (such as the sea urchins Strongylocentrotus purpuratus and Strongylocentrotus franciscanus) is also frequent.[5]

Human uses[edit]

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.[9]

Conservation status[edit]

Black abalone are listed on the International Union for Conservation of Nature's Red List as Critically Endangered (CR A4e).[8] On June 23, 1999, the U.S. National Marine Fisheries Service (NMFS) designated the black abalone as a candidate for protection under the Endangered Species Act (64 FR 33466). 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 (73 FR 1986). Black abalone were listed as endangered on January 14, 2009 (74 FR 1937). The NMFS proposed a critical habitat of 390 square kilometers for the endangered black abalone on September 28, 2010.[11] The State of California has introduced an Abalone Recovery Management Plan[12] 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.[9] 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.[9] Now, all abalone fisheries in California are managed by the California Department of Fish and Game, which restricts the size of abalones caught, and the season in which harvesting can take place.[8] In Mexico, there is a total allowable catch limit for black abalones.[8] Even though harvesting black abalone is regulated in California, poaching still occurs. Other threats include coastal development for residential areas, harbours and waste discharges, compounded by commercial and recreational fishing of the black abalone.[8]

The depleted stocks of black abalone were further reduced by Withering syndrome, first discovered in 1985, when commercial fishermen reported large numbers of empty shells and dying abalones on the shores of several of the Californian Channel Islands (including the islands of Santa Cruz, Anacapa, Santa Rosa, Santa Barbara, San Miguel, and San Clemente).[9][10] This 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, percentages greater than 90% of individuals have been lost, and in some places, a total loss of the black abalone population occurred.[8] 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.[5][13][14]

References[edit]

This article incorporates text from the ARKive fact-file "Black abalone" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.

  1. ^ a b Haliotis cracherodii Leach, 1814.  Retrieved through: World Register of Marine Species on 5 October 2010.
  2. ^ Oliver, A. P. H. (1975). The Hamlyn Guide to Shells of the World. The Hamlyn Publishing Group Limited. p. 320. ISBN 0-600-34397-9. 
  3. ^ a b c d Multi-Agency Rocky Intertidal Network[dead link] (February, 2005) - via ARKive
  4. ^ George Washington Tryon, Manual of Conchology vol. XII, p. 76 and 79; 1890
  5. ^ a b c d e f g h "Black Abalone (Haliotis cracherodii)". National Marine Fishery Services - Threatened & Endangered Species. NOAA. Retrieved 15 June 2010. 
  6. ^ Oliver, A.P.H. (2004). Guide to Seashells of the World. Buffalo: Firefly Books. 23.
  7. ^ Hogan, C. M. "Los Osos Back Bay". The Megalithic Portal. Retrieved 15 June 2010. 
  8. ^ a b c d e f g h listed on the IUCN Red List
  9. ^ a b c d e f g h Haaker, P. L.; et al. (2001). "Abalone". California’s Living Marine Resources: A Status Report. California Department of Fish and Game. pp. 89–97. Retrieved 15 June 2010. 
  10. ^ a b Lafferty, K. D.; Kuris, A. M. (1993). "Mass mortality of abalone Haliotis cracherodii on the California Channel Islands: tests of epidemiological hypotheses". Marine Ecology Progress Series 96: 239–248. doi:10.3354/meps096239. 
  11. ^ 75 FR 59900 : proposal for a critical habitat
  12. ^ Abalone Recovery Management Plan
  13. ^ Moore, J. D.; Finley, C. A; Robbins, T. T; Friedman, C. S. (2002). "Withering Syndrome and restoration of Southern California abalone populations". CalCOFI 43: 112–117. 
  14. ^ Bower, S.M. (2006). Withering Syndrome of Abalone. Retrieved February 9, 2009, from Fisheries and Oceans Canada Web site: http://www.pac.dfo-mpo.gc.ca/sci/shelldis/pages/fwsab_e.htm

Further reading[edit]

  • Geiger D.L. & Poppe G.T. (2000). A Conchological Iconography: The family Haliotidae. Conchbooks, Hackenheim Germany. 135 pp., 83 pls.
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