The White Abalone (Haliotis sorenseni) is a large gastropod mollusk that is distributed off the west coast of North America throughout the Southern California Bight and northern Baja California, a range of 900 km. It is found in rocky subtidal ocean waters, inhabiting rocky reefs or solitary outcrops adjacent to the sand–rock interface at depths of 20 to 60 meters from Point Conception in California (U.S.A.) south to Punta Abreojos, Baja California (Mexico). It grows slowly and has a lifespan on the order of 35 to 40 years. A variety of factors (notably, overfishing in the 1970s and 1980s) have led to dramatic population declines and in 2001 the White Abalone became the first endangered marine invertebrate to be listed under the Endangered Species Act of 1976 (see additional information from the NOAA Fisheries Office of Protected Resources), although at least one study (Butler et al. 2006) has yielded the encouraging finding that more potential White Abalone habitat is available than previously believed. Adult White Abalone, like other abalone species, are dependent upon macroalgae as their main source of nutrition. In addition, drifting macroalgae (such as fragments of the kelp Macrocystis pyrifera) appear to play an important role in facilitating the dispersal of juvenile and young adult White Abalone, apparently moving them far greater distances than could be traversed by the larvae during their 5 day dispersal phase. (McCormick et al. 2008 and references therein)
The white abalone, scientific name Haliotis sorenseni, is a species of large sea snail, a marine gastropod mollusk in the family Haliotidae, the abalones.[2]
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.
Historically the white abalone ranged from Point Conception, California to Baja California, Mexico, and was found especially on the offshore islands.[3]
In the most northerly part of the California 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.[3]
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.[3]
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.[3]
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.[3]
The white abalone usually has between 3-5 open holes (respiratory pores) in its shell. 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 10 in (25 cm), but are usually 5–8 in (13–20 cm).[3]
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.[3]
The white abalone is the deepest dwelling of eight species of California abalones, living at depths from 80 to 200 ft (24–61 m).[3] 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, upon which white abalone are known to feed.[3]
The white abalone is known to be a herbivore, grazing mainly on macroalgae, such as Laminaria farlowii and Agarum fimbriatum, and also several species of red algae.[3] Other species it eats include Chondracanthus exasperatus, Laminaria farlowii, Macrocystis pyrifera , and Palmaria mollis.[4]
Like many gastropods, white abalone have a complex life cycle involving larval stages. Fertilized eggs hatch into larvae; these larvae eventually metamorphose into the adult form and settle from the plankton to a hard substrate.[3] As broadcast spawning gastropods, white abalone reproduce by releasing their eggs and sperm into the surrounding water. If fertilized, the eggs hatch after only one day, but high concentrations of sperm are required in order for an egg to be fertilized. Therefore, aggregations of adult male and female abalone are necessary for successful fertilization to occur.[3]
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 yard. 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 decimated the populations of this species in seven years.
Considered a delicacy in California, white abalones, the rarest of the six abalone species in the state, have declined by over 99.99% due to increasing overfishing, in part illegal – the fishery was closed in 1996 – while at the same time, prices have escalated. Although white abalones 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.[5] 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 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.[6]
{{cite journal}}: CS1 maint: multiple names: authors list (link) The white abalone, scientific name Haliotis sorenseni, is a species of large sea snail, a marine gastropod mollusk in the family Haliotidae, the abalones.
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.
Haliotis sorenseni est une espèce de mollusques gastéropodes appartenant à la famille des Haliotididae.
Haliotis sorenseni is een slakkensoort uit de familie van de Haliotidae.[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1940 door Bartsch.
Bronnen, noten en/of referenties
Haliotis sorenseni (em inglês white abalone) é uma espécie de molusco gastrópode marinho pertencente à família Haliotidae. Foi classificada por Bartsch, em 1940. É nativa do nordeste do oceano Pacífico, em águas rasas da costa oeste da América do Norte.[1][2][3]
Abalones têm sido utilizados nesta área desde que o Homem chegou. Os americanos nativos comiam a carne de abalone, utilizando conchas inteiras como tigelas e pedaços de conchas para uso em anzóis, raspadores, miçangas, colares e decorações; até mesmo fazendo permutas com as conchas.[4] Sete espécies são descritas na região: Haliotis corrugata, H. cracherodii, H. fulgens, H. kamtschatkana, H. rufescens, H. sorenseni e H. walallensis.[5]
Concha fina e leve, oval,[2] com até 25 centímetros,[3] altamente arqueada. Exteriormente marrom-avermelhada[2][6] ou esverdeada.[7] Sua escultura de costelas espirais não raro se apresenta coberta por algas e tubos de organismos marinhos.[2][8] Os furos abertos na concha, de 3 a 5, são elevados e sua região interna se apresenta madreperolada, iridescente, com um brilho principalmente em rosa, tipicamente com nenhuma cicatriz muscular; e se presente, pouco diferenciada.[2][9] Lábio externo se estendendo sobre a área madreperolada, bastante fino e normalmente formando uma borda vermelha.[2][10]
Haliotis sorenseni ocorre em águas rasas, em profundidades de 5 até 45 metros,[2][3] mas geralmente fora da costa, entre 25 e 30 metros, em áreas rochosas do nordeste do oceano Pacífico, não sendo encontrada ao norte de Point Conception e apenas ocasionalmente em Point Dume, Palos Verdes e San Diego; mais abundante entre as ilhas do canal, em Santa Catalina, Santa Cruz, Santa Bárbara, San Clemente (Califórnia, Estados Unidos); também ocorrendo na Bahía Tortugas, Los Coronados e ilha de Cedros, na península da Baixa Califórnia (no oeste do México).[2][4]
Esta espécie tem uma das carnes mais suaves dentre os tipos comercializados de abalone,[4] porém sua pesca para a indústria de alimentos nos Estados Unidos se desenvolveu tarde devido a seu habitat de profundidade. Desembarques de pesca são relatados em 1968, com seu pico em 1972 e diminuição em seguida, até seu encerramento em 1993. Com sua densidade ainda em diminuição, por sua baixa reprodutibilidade e predação sobre a espécie, pesquisas foram realizadas para avaliar melhor o estado da população e explorar possibilidades de recolha de amostras para um programa de reprodução em cativeiro. Em maio de 2001, ele se tornou o primeiro invertebrado marinho a receber proteção federal nos Estados Unidos como uma espécie em extinção.[5] O molusco também é afetado por uma síndrome cujo agente é uma bactéria denominada Candidatus Xenohaliotis californiensis.[11]
|coautor= (ajuda) Haliotis sorenseni (em inglês white abalone) é uma espécie de molusco gastrópode marinho pertencente à família Haliotidae. Foi classificada por Bartsch, em 1940. É nativa do nordeste do oceano Pacífico, em águas rasas da costa oeste da América do Norte.
Abalones têm sido utilizados nesta área desde que o Homem chegou. Os americanos nativos comiam a carne de abalone, utilizando conchas inteiras como tigelas e pedaços de conchas para uso em anzóis, raspadores, miçangas, colares e decorações; até mesmo fazendo permutas com as conchas. Sete espécies são descritas na região: Haliotis corrugata, H. cracherodii, H. fulgens, H. kamtschatkana, H. rufescens, H. sorenseni e H. walallensis.
