This species hs no special conservation status.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Northern Pacific sea stars are able to perceive light stimuli and are positively phototactic. As previously mentioned, when four of five arms are shaded, a sea star will move with its illuminated ray forward. All other documented information about the communication and perception abilities of these sea stars regards sensory interactions between larval and adult forms. Larvae are capable of sensing metamorphosis inducing factors expelled by adults via use of neural cells that are held within the adhesive papillae on the external surface of the brachiolar arms.
Communication Channels: chemical
Perception Channels: visual ; tactile ; chemical
Northern Pacific sea stars are not generally preyed upon by other organisms. However, they may occasionally be eaten by Japanese sun stars (Solaster paxillatus). In Alaska, king crabs are known to feed on this species, and in laboratory settings, snails in the genus Charonia (tritons) have shown a preference for this species, as opposed to feeding on other marine life.
Known Predators:
Northern Pacific sea stars have five arms, all ending in small, upward-turned tips. Each of these arms joins in the center of the organism to form a central disc. This species shows a wide range of colors, from orange to yellow, and sometimes purple on their dorsal side. Irregularly arranged spines run down the length of each arm. A row of spines from each arm come together near the mouth area, creating a fan-like appearance. Spines also line the ventral groove of each arm, where the tube feet are found. This species can grow to be up to 50 cm in diameter.
Range length: 50 (high) cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; radial symmetry
Sexual Dimorphism: sexes alike
The average lifespan of a sea star is around 10 years, although many sea star species are able to live to about the age of 50. There is no specific information available regarding the lifespan of Northern Pacific sea stars.
Northern Pacific sea stars live in estuarine, intertidal, and coastal zones and prey on other marine inhabitants in or on the substrate. They are found near protected areas of coasts, far away from areas of the ocean with high wave action, at depths up to 220 meters. They prefer a slightly cold environment of about 7-10ºC; however, this species has adapted to the warmer waters of the Australian coast, which average about 22ºC. It can survive in a temperature range of 0–25ºC. Due to their presence in estuarine habitats, these sea stars are able to tolerate a large range of salinities, from 18.7-41.0 ppt.
Range depth: 220 (high) m.
Habitat Regions: temperate ; saltwater or marine
Aquatic Biomes: benthic ; coastal ; brackish water
Other Habitat Features: estuarine ; intertidal or littoral
Northern Pacific sea stars are found throughout parts of the Pacific Ocean near Japan, Russia, Northern China, and Korea as a native species. However, this species has also been introduced to oceanic habitats near parts of the southern Australian coast (especially Tasmania), Alaska and the Aleutian Islands, Europe, and the state of Maine.
Biogeographic Regions: nearctic (Introduced ); palearctic (Native ); australian (Introduced ); atlantic ocean (Introduced ); pacific ocean (Native )
Male and female sea stars release their respective gametes in to the aquatic environment. The gametes come together to form a fertilized egg, which undergoes holoblastic and radial cleavage followed by gastrulation, completing the beginning stages of larval development. The larva begins to feed once the gastrovascular canals are formed, and at this stage is called a bipinnaria. This stage later develops brachiolar arms, with three of them combining with a central adhesive disk to form the brachiolar complex. This marks the transition of the larva into the brachiolaria state. A brachiolarian larva can remain in the water column for about 120 days before it finally settles and undergoes metamorphosis into the adult sea star. Metamorphosis is induced by the detection of metamorphic inducing factors by the adhesive papillae on the brachiolar arms, such as chemical cues from adult sea stars in the environment. It takes a larva as little as 41 days to about 120 days, from the time of fertilization, to develop into an adult sea star. This process is all dependent upon the temperature of the water in which the sea star is developing; the warmer the water, the faster the rate of development.
Development - Life Cycle: metamorphosis
Northern Pacific sea stars are known to be voracious predators with a varied diet, essentially eating any type of animal that they encounter. Bivalves, such as mussels, scallops and clams compromise the largest part of this species' diet. They are known to pull apart the shell of these organisms with their arms, and then evert their stomachs into the shell cavity to digest their prey. This species also preys on gastropods, crabs, and barnacles. Occasionally, they have been seen exhibiting cannibalistic behavior when food sources are particularly low. This species has also been observed digging out buried prey from under the substrate, and feeding on algae.
Animal Foods: mollusks; aquatic crustaceans; echinoderms
Plant Foods: algae
Primary Diet: carnivore (Eats non-insect arthropods, Molluscivore )
Northern Pacific sea stars are an invasive species in some areas and an obligate predator whose presence has a great impact on benthic infauna, including mollusks, crustaceans, echinoderms, and other organisms that are preyed upon by this sea star. This species is known to host the bacterium Colwellia asteriadis, although negative effects on the sea star due to the presence of this microbe have not been described.
Commensal/Parasitic Species:
There are no known positive economic effects of Asterias amurensis on humans.
The negative economic effects of Northern Pacific sea stars are extensive. In their native Japan, they have devastated the shellfish industry. In Australia, the economic effects of the species are still being fully evaluated, but it is thought that if their spread continues, the soft sediment communities along the coast of Australia may be compromised. It is evident that several fisheries have been negatively impacted – there has been an estimated one billion dollar loss in the industry in Tasmania. Because these fishing industries are important to the economy of the region, several “sea star hunting days” have been organized in which several thousand sea stars have been removed from the coasts. Northern Pacific sea stars are also on the Global Invasive Species Database's list of the 100 Worst Invasive Species.
Female Northern Pacific sea stars release their eggs into the surrounding marine environment; they are then externally fertilized by sperm released by male sea stars. This species reproduces seasonally and spawns during the months of January to April in Japan and during the months of June to October in Russia and Australia.
Mating System: polygynandrous (promiscuous)
Sexual maturity occurs in both males and females when they are 3.6-5.5 cm in length. Females can be identified for 5-6 months of the year due to the presence of their maturing ovaries. Mature ovaries are characterized by the constant release of eggs as well as their orange color. Females are capable of carrying about 10-25 million eggs. Males are also reproductively mature for about 6 months of the year, with maturity being characterized by the yellowish-brown color of the testes. These sea stars have ectosomatic organs, meaning that the pores for gamete expulsion are in direct contact with the marine environment. As gametes are released, they are replaced by constantly ongoing gametogenesis within the gonads. Spawning usually occurs in the late winter and early spring months, continuing into the summer.
Breeding interval: This species has an annual breeding season, during which individuals may spawn several times.
Breeding season: Spawning usually occurs in the late winter to early spring.
Range number of offspring: 10,000,000 to 25,000,000.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; asexual ; fertilization (External ); broadcast (group) spawning; oviparous
Gametes are released freely into the environment, and offspring develop independently of the parents.
Parental Investment: no parental involvement
Hvězdice amurská (Asterias amurensis) je ostnokožec − hvězdice, zařazený do řádu Forcipulatida, čeledi Asteriidae a rodu Asterias. Popis druhu učinil dánský přírodovědec Christian Frederik Lütken v roce 1871 a existuje několik vědeckých synonym. Hvězdice dává přednost pobřežním vodám. Původní areál výskytu hvězdice amurské zahrnoval pobřeží na východě Asie, jako je například u Japonska nebo Ruska či Koreji, avšak došlo k introdukci na nová území; druh se může dostávat do nových areálů například pomocí lodí. Areál výskytu se tak rozšířil kupříkladu na pobřeží Evropy, Aljašky nebo Austrálie, kam byl druh zavlečen během 80. let 20. století, a přilehlé Tasmánie; zde je výskyt zaznamenán od roku 1986. Přestože jinak žije o teplotě vody maximálně 10 °C, ani život v teplejším prostředí pro hvězdici nepředstavuje problém. Pro schopnost rychle se rozmnožovat (během dvou let se v Port Philip Bay namnožily až na 12 milionů hvězdic a roku 2000 jich zde žilo zhruba 75 milionů) a velkou žravost patří hvězdice amurská mezi invazní druhy a je škodlivá. Jako predátor, konzumující velkou škálu různé potravy, představuje nebezpečí pro ostatní živočichy (měkkýši) a rovněž žere rybářům jejich úlovky. Přínosnost pro lidi je nulová, i když se uvažovalo o prodeji jako suvenýry.
Hvězdice amurská má celkem pět ramen, její velikost se vyšplhá až na půl metru. Pohybuje se pomocí trubičkovitých končetin. Tělo tohoto druhu může být zbarveno různými barvami, spodní strana je nicméně vždy žlutá. Hvězdice amurská má oddělená pohlaví, samec i samice jsou si však nicméně vzájemně podobní (nevyvinul se pohlavní dimorfismus). Doba rozmnožování závisí na ročním období. Oplodnění probíhá vně těla, samičky vypouštějí i 25 milionů vajíček a samci své spermie, které se spojí ve vodě a zde také probíhá vývoj následných larev. Ten trvá kolem dvou až čtyř měsíců; poté malé hvězdice začnou žít na pevnině jako dospělci. Během prvního roku rostou rychlostí až 6 mm za měsíc, později se vývoj zpomalí. Při velikosti 4,5 až 5 cm se již mohou rozmnožovat a dožívají se dvou až tří let. Hvězdice amurská má několik přirozených nepřátel, například jiné hvězdice Solaster paxillatus a Coscinasterias muricata, kraba kamčatského (Paralithodes camtschaticus) a kraba Leptomithrax gaimardii.
Obrázky, zvuky či videa k tématu hvězdice amurská ve Wikimedia Commons
Hvězdice amurská (Asterias amurensis) je ostnokožec − hvězdice, zařazený do řádu Forcipulatida, čeledi Asteriidae a rodu Asterias. Popis druhu učinil dánský přírodovědec Christian Frederik Lütken v roce 1871 a existuje několik vědeckých synonym. Hvězdice dává přednost pobřežním vodám. Původní areál výskytu hvězdice amurské zahrnoval pobřeží na východě Asie, jako je například u Japonska nebo Ruska či Koreji, avšak došlo k introdukci na nová území; druh se může dostávat do nových areálů například pomocí lodí. Areál výskytu se tak rozšířil kupříkladu na pobřeží Evropy, Aljašky nebo Austrálie, kam byl druh zavlečen během 80. let 20. století, a přilehlé Tasmánie; zde je výskyt zaznamenán od roku 1986. Přestože jinak žije o teplotě vody maximálně 10 °C, ani život v teplejším prostředí pro hvězdici nepředstavuje problém. Pro schopnost rychle se rozmnožovat (během dvou let se v Port Philip Bay namnožily až na 12 milionů hvězdic a roku 2000 jich zde žilo zhruba 75 milionů) a velkou žravost patří hvězdice amurská mezi invazní druhy a je škodlivá. Jako predátor, konzumující velkou škálu různé potravy, představuje nebezpečí pro ostatní živočichy (měkkýši) a rovněž žere rybářům jejich úlovky. Přínosnost pro lidi je nulová, i když se uvažovalo o prodeji jako suvenýry.
Hvězdice amurská má celkem pět ramen, její velikost se vyšplhá až na půl metru. Pohybuje se pomocí trubičkovitých končetin. Tělo tohoto druhu může být zbarveno různými barvami, spodní strana je nicméně vždy žlutá. Hvězdice amurská má oddělená pohlaví, samec i samice jsou si však nicméně vzájemně podobní (nevyvinul se pohlavní dimorfismus). Doba rozmnožování závisí na ročním období. Oplodnění probíhá vně těla, samičky vypouštějí i 25 milionů vajíček a samci své spermie, které se spojí ve vodě a zde také probíhá vývoj následných larev. Ten trvá kolem dvou až čtyř měsíců; poté malé hvězdice začnou žít na pevnině jako dospělci. Během prvního roku rostou rychlostí až 6 mm za měsíc, později se vývoj zpomalí. Při velikosti 4,5 až 5 cm se již mohou rozmnožovat a dožívají se dvou až tří let. Hvězdice amurská má několik přirozených nepřátel, například jiné hvězdice Solaster paxillatus a Coscinasterias muricata, kraba kamčatského (Paralithodes camtschaticus) a kraba Leptomithrax gaimardii.
Der Nordpazifische Seestern (Asterias amurensis) ist eine Art der Seesterne aus der Ordnung der Zangensterne (Forcipulatida), der an den Küsten Chinas, Koreas, Russlands und Japans heimisch ist. Er ist als invasive Art in andere Erdteile verschleppt worden, darunter Australien, Nordamerika und Europa.
Der Nordpazifische Seestern erreicht einen Durchmesser von bis zu 50 cm und hat fünf Arme, deren Enden nach oben gebogen sind. Die Oberseite ist orange bis gelb, manchmal violett gefärbt. Die Arme sind mit unregelmäßig angeordneten Stacheln versehen. Von jedem Arm verläuft eine Reihe Stacheln in Form eines Fächers bis in die Mitte des Seesterns. Auch auf der Unterseite jedes Arms verläuft entlang der Ambulacralfurche eine Reihe Stacheln.
Der Nordpazifische Seestern ist an den Küsten des Pazifik in Japan, Russland, dem nördlichen China und Korea heimisch. Als invasive Art tritt er an der südlichen Küste Australiens, in Tasmanien, Alaska, den Aleuten, Europa und Maine (USA) auf. Er kommt in Flussmündungen und geschützten Bereichen der Küstenzonen bis 220 m Tiefe vor und bevorzugt Temperaturen von 7 ºC bis 10 ºC, doch ist er in Australien in Küstenbereichen mit durchschnittlich 22 ºC warmem Wasser zu finden. Er verträgt Temperaturen von 0 ºC bis 25 ºC und einen Salzgehalt von 1,87 bis 4,10 Prozent.
Asterias amurensis frisst vorzugsweise Muscheln, darüber hinaus aber Fischeier und zahlreiche Tiere wie Schnecken, Rankenfußkrebse, Seeigel, Seesterne und Zehnfußkrebse. Kannibalismus kommt bei Nahrungsmangel vor. Der Seestern vermag auch eingegrabene Tiere auszugraben. Die Beute wird extraintestinal verdaut.
Wie die meisten Seesterne ist Asterias amurensis getrenntgeschlechtlich. Während der Paarungszeit kommen Weibchen und Männchen zusammen und geben ihre Keimzellen ins Wasser ab. Dies ist in Japan zwischen Januar und April und in Russland und Australien zwischen Juni und Oktober. Die im freien Wasser befruchteten Eier entwickeln sich über eine frei schwimmende Bipinnaria-Larve zu einer Brachiolaria-Larve. Je nach Temperatur etwa 41 bis 120 Tagen nach Befruchtung verankert sich die Larve mit ihrer Haftscheibe am Grund und macht die Metamorphose zum Seestern durch.
Sowohl Männchen als auch Weibchen werden bei einem Körperdurchmesser von etwa 3,6 cm bis 5,5 cm geschlechtsreif. Etwa 5 bis 6 Monate im Jahr können Weibchen an ihren orangefarbenen Eierstöcken und den beständig ins Wasser abgegebenen Eizellen erkannt werden. Von einem Weibchen werden etwa 10 bis 25 Millionen Eier produziert. Männchen sind in den 6 Monaten ihrer sexuellen Produktivität im Jahr an der gelblich-braunen Farbe ihrer Hoden erkennbar.
Der Nordpazifische Seestern hat nur wenige Fressfeinde. In Alaska wurden Königskrabben (Paralithodes camtschaticus) beim Fressen nordpazifischer Seesterne beobachtet. In Laborversuchen bevorzugten Tritonshörner (Charonia) den Asterias amurensis gegenüber anderen Arten als Beutetier. Als weiterer möglicher Feind gilt der Japanische Sonnenstern (Solaster paxillatus).
Als invasive Art hat Asterias amurensis an vielen Orten die Populationen einheimischer Arten von Weichtieren, Stachelhäutern und Krebsen drastisch reduziert. Auf Grund des Verzehrs von Fischeiern wird er in Australien mit Rückgang des gefährdeten Handfisches Brachionichthys hirsutus in Zusammenhang gebracht. Die Verbreitung des Seesterns erfolgt als Larve im Ballastwasser von Schiffen. Auf Grund der großen Bedrohung, die von diesem Seestern für die Artenvielfalt ausgeht, ist Asterias amurensis in die „Liste der 100 schlimmsten invasiven Arten“ (100 of the world’s worst invasive alien species) aufgenommen worden.[1]
Der Nordpazifische Seestern (Asterias amurensis) ist eine Art der Seesterne aus der Ordnung der Zangensterne (Forcipulatida), der an den Küsten Chinas, Koreas, Russlands und Japans heimisch ist. Er ist als invasive Art in andere Erdteile verschleppt worden, darunter Australien, Nordamerika und Europa.
Asterias amurensis, also known as the Northern Pacific seastar and Japanese common starfish, is a seastar found in shallow seas and estuaries, native to the coasts of northern China, Korea, far eastern Russia, Japan, Alaska, the Aleutian Islands and British Columbia in Canada. Two forms are recognised: the nominate and forma robusta from the Strait of Tartary. It mostly preys on large bivalve molluscs, and it is mostly preyed on by other species of starfish. Population booms in Japan can affect the harvest of mariculture operations and are costly to combat.
This species has been introduced to oceanic areas of southern Australia, and is an invasive species there causing damage to native species, especially in Tasmania.[2][3]
It is known in English vernacular as the northern Pacific seastar,[4][1] flatbottom seastar, Japanese seastar, Japanese starfish, north Pacific seastar, purple-orange seastar[4] and Japanese common starfish.[1]
This species was first described in 1871 by Christian Frederik Lütken.[1][5] Parasterias albertensis was described in 1914 from British Columbia by Addison Emery Verrill from a collection made late in the previous century and kept at the Smithsonian;[6] this taxon was synonymised by Walter Kenrick Fisher in 1930.[1][7][8]
Walter Kenrick Fisher also subsumed Asterias rollestoni as a forma of A. amurensis in 1930,[9][7] and further stated that A. versicolor might well intergrade with his A. amurensis f. rollestoni to the north of its range.[7] In 1936, and subsequently in 1940, Ryori Hayashi followed Fisher's interpretation, in 1940 even subsuming Asterias versicolor as a form of A. amurensis,[10] although Alexander Michailovitsch Djakonov in 1950 and subsequent authors have rejected this taxonomic interpretation.[9][8]
Asterias pectinata was described from Kamchatka by Johann Friedrich Brandt in 1834 or 1835, and synonymised with Asterias amurensis by Fisher in 1930.[1][7][11]
In the 1950 work Sea stars (Asteroids) of the USSR Seas (translation) Djakonov named five new forms of this species from the far eastern Soviet Union (recognising six forms including the nominate),[9] although these were later all synonymised, except for one: f. robusta.[1]
There are two forms (or subspecies) are accepted in the World Register of Marine Species by Christopher Mah as of 2008:[1]
It can grow up to 50 cm in diameter,[2][4][12] although this is exceptional and the arms usually grow to 16.1 cm, with the ratio between the length of the arm and the radius of its disc ranging from 3.6:1 to 5.9:1.[9] It has five arms[4][6] and a small central disk.[4] It can be distinguished from similar species by the distinctive upturned tips of its arms.[2][4] The underside is completely yellow.[4] It shows a wide range of colours on its dorsal side: orange to yellow, sometimes red and purple.[2][4] The arms are unevenly covered with small, jagged-edged spines, which line the groove in which the tube feet lie, and join up at the mouth in a fan-like shape.[4]
According to Verrill it most resembles the species Asterias forbesi and A. rubens from the north Atlantic. It is distinguished by its lack of interactinal plates and the evenly reticulated arrangement of the dorsal plates.[6]
It is native to the coastal seawaters of northern China,[2][4] North[4] and South Korea,[2][4] far eastern Russia,[2] Japan,[1][2][4][12] the Aleutian Islands,[1] Alaska[1] (from the Bering Sea to the Gulf of Alaska)[12] and Canada (British Columbia).[1][12] It is found throughout the Sea of Japan. It is common within its native range.[12]
In Japan it is found on both coasts from Hokkaido to (northern) Kyushu and in the Seto Inland Sea: in Mitsu Bay off the coast of Yokohama, in Aomori Prefecture off the coast of Odanozawa and elsewhere, along the coast of Yamagata Prefecture, Tokyo Bay, between Tateishi and Ogashima in Sagami Bay off Nagai, off Hayama, in Karatsu Bay, Hakata Bay, Osaka Bay, Ise Bay, Sendai Bay and Ariake Bay.[12]
In South Korea it is found on both the Pacific and the Sea of Japan coasts and has been found in Dokdo, Geoje Island, Jangmok and Tongyeong.[12]
In Russia it is found in the Peter the Great Gulf in Primorsky Krai, in the Chukotka Autonomous Okrug in the eastern Chukchi Sea to the Arctic Ocean,[12] Kamchatka,[11] the Kuril Islands, both east and west shores of Strait of Tartary and on both coasts of Sakhalin.[12]
In Canada it was collected in 1887 northeast of Vancouver Island, British Columbia,[6] although records from Canada and Alaska may represent accidental human introductions. [13]
This species has been introduced to oceanic areas of Tasmania in southern Australia, parts of Europe and Maine.[2] It was first collected in 1982 and first reported in 1985 in the Derwent River estuary in Tasmania, and first reported in Victoria, Australia in 1998.[12] It has become an invasive species in Australia and is on the Invasive Species Specialist Group list of the world's 100 worst invasive species.[14]
They prefer a slightly cold environment of about 7–10 °C.[2] The optimum temperature is also said to be 9–13 °C.[12] It has a temperature tolerance of 0–25 °C according to one source,[2] or 5–20 °C according to another.[12] It is able to tolerate a large range of salinities, from 18.7–41.0 ppt., and can survive in estuaries.[2] It has been found at a maximum depth of 220m.[2][4]
It prefers shallow, sheltered areas. Adults are found on a wide range of substrates, including kelp forests, mud, sand, pebbles, rock, flotsam, nets and artificial substrates. It is not found in areas of high wave action or on reefs.[12]
These seastars move towards light.[2] The adults are mobile with a top speed of 20 cm/minute. Tagged seastars in Tokyo Bay, Japan, logged maximum travel distances 2.5 km in 32 days (78m/day) in the west of the bay, and 8.1 km in 129 days (62.8m/day) at the east. The population goes through boom-and-bust cycles in Japan, where it can swarm on occasions; during swarms the adults can float on the sea surface due to air retained within the body cavity. The population is mixed, with different age groups found intermingled. The animals can survive at least four years in the wild in Japan, but it is estimated that most live to two to three years. If the seastar is ripped apart, each arm can grow into a new animal (fissiparity) if a part of the main disk is attached. This is not entirely uncommon.[12]
Male and female seastars release their gametes into the seawater (external fertilization),[2][12] resulting in fertilised eggs. These go through gastrulation and become larvae. Once these begin to feed they are called bipinnaria, this stage then grows into the brachiolaria after growing five arms, three fused with the central disk.[2] The development is temperature-dependant.[2][12] These larvae float as pelagic plankton[12] from 41 to 120 days before they find and settle on a surface and metamorphose into juvenile sea stars. This metamorphosis in larvae is stimulated by chemicals detected in the presence of adults and of tactile stimuli (feeling a surface).[2] The first year these juveniles grow 6mm a month, thereafter they grow 1–2mm a month.[4] Males and females can be sexually mature when they reach 3.6–5.5 cm in length,[2][12] but by far most males and females reproduce when around 10 cm in diameter, when they are 1 year old.[12] The species reproduces seasonally and spawns from January to April in Japan, from June to October in Russia,[2] and between July and October in Australia.[4] Females are capable of carrying up to 20 million eggs.[2][4] Gametogenesis in females takes 9 months. Females spawn (release eggs) successively during the breeding season. In Japan it may spawn in two main events in the year, elsewhere it is once.[12]
It is a generalist predator, but primarily preys on large bivalve mollusc species.[2][12] It pulls their wings apart with all five arms and then everts its stomach into the shell. It can dig clams out of the seabed on occasion.[2] It can be selective or opportunistic depending on availability of prey.[12] It sometimes also preys on gastropods, crabs, barnacles, ascidians, sea squirts and algae.[2][12] It has also been seen preying on itself during periods of low food abundance.[2] It will also eat dead fish and fish waste.[4][12]
In Tasmania it preys on the egg masses of the spotted handfish and the ascidians on which they spawn.[12]
In Japan, the sunstar Solaster paxillatus eats this species.[2][4][12] It is preyed upon by the spiny sand seastar Luidia quinaria in Tokyo Bay.[12] In aquaria in Alaska, king crabs (Paralithodes camtschaticus) were recorded feeding on this seastar.[2][12] In laboratory experiments in Korea, Charonia sp. (trumpet snail) were found to prefer this species above other seastars, sea cucumbers and sea urchins.[12]
In Japan, the scuticociliates Orchitophrya stellarum and another Orchitophrya sp. are known to parasitise the gonads of this seastar, especially the males. O. stellarum infects testes and feeds on the gonads of various seastar species. It can cause castration and be lethal for Asterias amurensis in Japan. Other possible parasites found associated with these seastars are the skeleton shrimps Caprella astericola, the copepod Scottomyzon gibberum, the polychaete scaleworm Arctonoe uittuta, species from the harpacticoid copepods genera Parathalestris, Thalestris, Paramphiacella and Eupelite, as well as several unidentified gammaridean amphipods and an unidentified apicomplexan living within it.[12]
In Japan it is abundant at 20m depth, but decreases to 50m, where it is replaced by another seastar species, Distolasterias nipon.
It competes with the starfish Uniophora granifera and Coscinasterias muricata, and Pacific walruses, Odobenus rosmarus ssp. divergens, for bivalve prey.[4]
A possible commensal is the bacterium Colwellia asteriadis, a new species published in 2010, which has only been isolated from Asterias amurensis hosts in the sea off Korea. These showed no effects from hosting the bacteria.[2][15][16]
It is considered useful in traditional medicine in China and is in the 2015 Pharmacopoeia of the People's Republic of China no.[17]
It is a predator which can impact the abundance of juvenile bivalves.[18] The asteroid stage can attach itself to salmon traps, oyster lines and scallop longlines. In Japan, where it is native, population outbreaks have cost the mariculture industry millions of dollars in control measures and losses from predation.[2][12][18] It can have significant impact on Mizuhopecten yessoensis scallop plantations and populations of Fulvia tenuicostata and Patinopecten yessoensis in Japan, and some impact on mussels and oysters in Tasmania.[12]
This seastar is an invasive species in Australia.[18] It has colonised Australian waters in the Derwent Estuary, Port Phillip Bay and Henderson Lagoon in Tasmania.[2][12] In the Derwent Estuary, the Northern Pacific seastar has been connected to the decline of the endemic endangered spotted handfish.[19][20][21]
The most likely mechanism of introduction is the transport of free-swimming larvae in ballast water for ships. The ships suck in the ballast water containing seastar larvae, in a port such as one in Japan, and let it out in a port such as one in Tasmania, the larvae come out with the water, and metamorphose into juvenile sea stars.[2][3][22]
Trials have been run to find effective removal processes including physical removal of A. amurensis, which was estimated by workshop participants to be the most effective, safe and politically attractive when compared with chemical or biological control processes.[23] Several "sea star hunting days" have been organized in Tasmania in which several thousand sea stars have been removed.[2] Mountfort et al. studied developing a probe to test ballast water and detect the presence of this specific maritime pest. Early detection remains the best solution to reducing harmful effects of invasive species.[24]
The population has not been assessed by the IUCN.[2]
Media related to Asterias amurensis at Wikimedia Commons
Data related to Asterias amurensis at WikispeciesAsterias amurensis, also known as the Northern Pacific seastar and Japanese common starfish, is a seastar found in shallow seas and estuaries, native to the coasts of northern China, Korea, far eastern Russia, Japan, Alaska, the Aleutian Islands and British Columbia in Canada. Two forms are recognised: the nominate and forma robusta from the Strait of Tartary. It mostly preys on large bivalve molluscs, and it is mostly preyed on by other species of starfish. Population booms in Japan can affect the harvest of mariculture operations and are costly to combat.
This species has been introduced to oceanic areas of southern Australia, and is an invasive species there causing damage to native species, especially in Tasmania.
Asterias amurensis, también denominada estrella de mar del Pacífico Norte y estrella de mar japonesa común, es una especie de estrella de mar nativa de las costas del norte de China, Corea, Rusia y Japón.[1] Esta especie fue introducida en las zonas oceánicas de Tasmania, sur de Australia, Alaska, y las islas Aleutianas, partes de Europa, y Maine.[1] Tomando como referencia la distribución de las poblaciones de estrella de mar del Pacífico del Norte en puertos y rutas marinas, el mecanismo más probable de introducción es el transporte de larvas presentes en el mar en los balastos de agua de los barcos. Los barcos cargan sus tanques de balasto con agua que contienen larvas de estrella de mar, en un puerto por ejemplo en Japón, y devuelven el agua al mar en otro puerto como por ejemplo en Tasmania, donde las larvas son liberadas junto con el agua de balasto, y sufren su metamorfosis transformándose en juveniles de estrella de mar.
Esta especie se ha convertido en una especie invasora en Australia y se encuentra en la lista de las 100 especies exóticas invasoras más dañinas del mundo del Grupo de Especialistas de Especies Invasoras..[2]
Las invasiones por esta especie conducen a extinciones de otras especies de animales marinos. Es muy importante monitorear los impactos ecológicos debidos a especies invasoras ya que pueden causar impactos económicos o sobre la salud del ser humano. Un crecimiento abrupto de la población de esta especie afectará las poblaciones de sus presas y sacará de su equilibrio normal a la red trófica propia de las zonas costeras del Pacífico. La evidencia experimental permite concluir que la estrella de mar depreda produciendo un gran impacto a los juveniles de bivalvos. La estrella se adhiere a las trampas para salmones, líneas de ostras y scallop longlines.[3] En Australia, estuvo asociada con la declinación de las poblaciones del "pez con manos" que es una especie amenazada. Como las redes tróficas cambian a lo largo del tiempo, la amenaza y pérdida de ciertos organismos marinos comercializables causa que las comunidades costeras lleguen a sufrir pérdidas potenciales de miles de millones de dólares. En Japón, los episodios de desarrollo explosivo de la población de la estrella de mar le han costado a la industria pesquera millones de dólares en medidas de control y pérdidas por depredación.[3]
Esta especie ya ha invadido las aguas de Australia en el estuario Derwent y la Henderson Lagoon. Todavía no se ha detectado su presencia en las aguas de América del Norte.
Se han realizado pruebas para buscar procesos efectivos de remoción incluida la remoción de los propios animales de A. amurensis, la cual es considerada por lo especialistas el método más efectivo, seguro y políticamente atractivo comparado con procesos de control mediante químicos o biológicos.[4] El envenenamiento de las estrellas de mar o introducir un nuevo depredador para reducir el tamaño de sus poblaciones acarrearía otros problemas, por lo que no es posible garantizar la efectividad de estas opciones. La detección temprana y la prevención de la reproducción es ahora la mejor solución para reducir los efectos dañinos de esta especie invasora. El objetivo del trabajo de Mountfort et al. fue desarrollar un método de análisis del agua de balasto y detectar la presencia de esta peste marina específica.[5] Si se aplican las políticas sobre gestión del agua de los balastos, se reduciría la frecuencia con la que la estrella de mar podría ser introducida en sistemas foráneos.
Datos: Q1140786
Multimedia:
Especies: Asterias amurensis
Asterias amurensis, también denominada estrella de mar del Pacífico Norte y estrella de mar japonesa común, es una especie de estrella de mar nativa de las costas del norte de China, Corea, Rusia y Japón. Esta especie fue introducida en las zonas oceánicas de Tasmania, sur de Australia, Alaska, y las islas Aleutianas, partes de Europa, y Maine. Tomando como referencia la distribución de las poblaciones de estrella de mar del Pacífico del Norte en puertos y rutas marinas, el mecanismo más probable de introducción es el transporte de larvas presentes en el mar en los balastos de agua de los barcos. Los barcos cargan sus tanques de balasto con agua que contienen larvas de estrella de mar, en un puerto por ejemplo en Japón, y devuelven el agua al mar en otro puerto como por ejemplo en Tasmania, donde las larvas son liberadas junto con el agua de balasto, y sufren su metamorfosis transformándose en juveniles de estrella de mar.
Esta especie se ha convertido en una especie invasora en Australia y se encuentra en la lista de las 100 especies exóticas invasoras más dañinas del mundo del Grupo de Especialistas de Especies Invasoras..
Asterias amurensis on Asteriidae-heimoon kuuluva suurikokoinen meritähtilaji. Lajia tavataan eri puolilla Tyyntämerta. Se on alun perin kotoisin Tyynenmeren pohjoisosista, mutta on levinnyt etelämmäs. Sitä pidetään nykyisin yhtenä maailman sadasta haitallisimmasta vieraslajista.[1]
Tämä meritähti voi kasvaa halkaisijaltaan 40–50 cm:n mittaiseksi. Keskikiekko on suhteessa sakaroihin pieni. A. amurensis on yleisväriltään keltainen, sakaroissa on punaisia tai violetinsävyisiä kuvioita. Tähden alapinta on tasaisenkeltainen ja pienten nystermämäisten piikkien peittämä.[1]
A. amurensis elää suojaisissa, matalissa vesissä eikä sitä tavata niissä koralliriuttojen osissa, joita aallot runtelevat. Se menestyy parhaiten, kun veden lämpötila on 7–10 °C, mutta sietää Australian 22-asteista vettä, jopa +25 asteeseen asti.[1]
A. amurensis lisääntyy sekä suvullisesti että suvuttomasti. Suvullista lisääntymistä tapahtuu talvella, jolloin naaras voi laskea 10–25 miljoonaa munaa. Suvuton lisääntyminen tapahtuu jakautumalla: jokainen osa, jossa on vähänkin keskikiekkoa, voi kasvaa uudeksi yksilöksi.[2]
Asterias amurensis on Asteriidae-heimoon kuuluva suurikokoinen meritähtilaji. Lajia tavataan eri puolilla Tyyntämerta. Se on alun perin kotoisin Tyynenmeren pohjoisosista, mutta on levinnyt etelämmäs. Sitä pidetään nykyisin yhtenä maailman sadasta haitallisimmasta vieraslajista.
Tämä meritähti voi kasvaa halkaisijaltaan 40–50 cm:n mittaiseksi. Keskikiekko on suhteessa sakaroihin pieni. A. amurensis on yleisväriltään keltainen, sakaroissa on punaisia tai violetinsävyisiä kuvioita. Tähden alapinta on tasaisenkeltainen ja pienten nystermämäisten piikkien peittämä.
A. amurensis elää suojaisissa, matalissa vesissä eikä sitä tavata niissä koralliriuttojen osissa, joita aallot runtelevat. Se menestyy parhaiten, kun veden lämpötila on 7–10 °C, mutta sietää Australian 22-asteista vettä, jopa +25 asteeseen asti.
A. amurensis lisääntyy sekä suvullisesti että suvuttomasti. Suvullista lisääntymistä tapahtuu talvella, jolloin naaras voi laskea 10–25 miljoonaa munaa. Suvuton lisääntyminen tapahtuu jakautumalla: jokainen osa, jossa on vähänkin keskikiekkoa, voi kasvaa uudeksi yksilöksi.
Asterias amurensis est une espèce d'étoiles de mer devenue invasive dans le sud de l'Australie.
C'est une étoile régulière à 5 bras, à la cuticule généralement violette. Elle peut mesurer jusqu'à 50 cm de diamètre[1].
Face orale
gros plan.
On rencontre cette étoile dans le nord du Pacifique tempéré, du Japon à l'Alaska[1].
Importée par ballast à l'état larvaire, elle est devenue invasive dans le sud de l'Australie, où elle met en danger l'écosystème côtier[2].
Asterias amurensis est une espèce d'étoiles de mer devenue invasive dans le sud de l'Australie.
Asterias amurensis is een zeester uit de familie Asteriidae. De wetenschappelijke naam van de soort werd in 1871 gepubliceerd door Christian Frederik Lütken.[1]
De kleur is grotendeels geel; aan de bovenzijde zijn oranje vlekken aanwezig die ook het gehele lichaam kunnen bedekken.
De soort wordt van nature gevonden in het noorden van de Stille Oceaan, maar heeft zich door menselijk toedoen ook in Australische wateren gevestigd. Doordat hij aanzienlijke ecologische en economische schade kan aanrichten, wordt de soort door een commissie van de IUCN tot 's werelds ergste invasieve soorten gerekend[2] Gevreesd wordt dat de soort op termijn gelijkaardige schade kan veroorzaken in Europa.
Bronnen, noten en/of referenties
Wikimedia Commons'ta Asterias amurensis ile ilgili çoklu ortam belgeleri bulunur. 
Wikispecies'te Asterias amurensis ile ilgili detaylı taksonomi bilgileri bulunur. Asterias amurensis, Asteriidae familyasında sınıflandırılan bir denizyıldızı türüdür. Asıl olarak Çin'in kuzey kıyıları, Kore, Rusya ve Japonya'da bulunur.[1] Bu denizyıldızı türü Tazmanya, Avustralya'nın güneyi, Alaska, Aleut Adaları, Avrupa'nın bir bölümü ve Maine eyaletine sokulmuştur.[1] Denizyıldızının limanlardaki popülasyonları gözönüne alındığında bu sokulmanın nedeninin gemilerin sintine suyu ile denizde bulunan larvaları taşımaları olduğu düşünülmektedir. Özellikle Avustralya'da en yayılmacı türlerden biri hâline gelmiştir.[2]
Çoğu denizyıldızı gibi beş kollu olan bu tür genellikle mor renklidir. Boyu 50 cm'ye ulaşabilir.
Asterias amurensis, Asteriidae familyasında sınıflandırılan bir denizyıldızı türüdür. Asıl olarak Çin'in kuzey kıyıları, Kore, Rusya ve Japonya'da bulunur. Bu denizyıldızı türü Tazmanya, Avustralya'nın güneyi, Alaska, Aleut Adaları, Avrupa'nın bir bölümü ve Maine eyaletine sokulmuştur. Denizyıldızının limanlardaki popülasyonları gözönüne alındığında bu sokulmanın nedeninin gemilerin sintine suyu ile denizde bulunan larvaları taşımaları olduğu düşünülmektedir. Özellikle Avustralya'da en yayılmacı türlerden biri hâline gelmiştir.
Має широкий центральний диск, від якого відходять 5 широких, сплющених, з тонкими, майже гострими, бічними краями, загострених на кінцях променів, розмах яких у великих форм досягає 30 см. Черевна сторона дуже плоска. Спинні голки дрібні, зазвичай тупо-конусоподібні, одиночні. Найбільші з них іноді розташовуються по середній лінії променя. Забарвлення дуже мінливе, варіює від охристого до темно-фіолетового, але переважають жовтувато-бурі, іноді рожево-бурі форми.
Зустрічається на північному заході Тихого океану біля берегів північного Китаю, Кореї, Росії і Японії. Цей вид був випадкового завезений в океанічних областях Тасманії, Австралії, Аляски, Алеутських островів, частини Європи і штату Мен .
Зустрічаються на літоралі до глибин 30-40 м, глибше рідкісні. Воліють піщані і кам'янисті ґрунти. На літоралі трапляються серед каменів і заростей водоростей. На великих зарослях водоростей молодь утворює величезні скупчення («дитячі садки»), дрібним бісером покриваючи поверхню макрофітів. Ця морська зірка нерідко зустрічається у забруднених людиною бухтах, де інші види зірок вже не виживають. Це хижаки, що нападають на молюсків (гребінці, устриці, мідії) та інших голкошкірих, і трупоїди. У місцях великих скупчень нерідко спостерігається канібалізм. Іноді під водою можна спостерігати своєрідні «кулі» з багатьох астерій, що обліпили жертву вивернутими шлунками.
Період нересту розтягнутий і зазвичай складається з двох етапів: червень-липень і вересень. Астерії утворюють щільні нерестові скупчення. Цікава нерестова поведінка цих зірок. Самки піднімаються над ґрунтом на променях і їх статеві продукти скупчуються між променями у вигляді невеликих (2-3 см) помаранчевих горбків. Самці повзають навколо самок, злегка піднімаючи центральну частину і викидають свої статеві продукти білого кольору. Потім зірки обох статей починають повзати в районі нерестовищ, одночасно перемішуючи статеві продукти і охороняючи їх від риб і різних ракоподібних. Такий тип поведінки також можна назвати турботою про потомство. Личинка планктотрофна (тобто живиться планктоном).
Asterias amurensis, còn được gọi là Sao biển Bắc Thái Bình Dương, là một loài sao biển có nguồng gốc ở bờ biển phía bắc Trung Quốc, Hàn Quốc, Nga và Nhật Bản.[1] Loài này đã được giới thiệu đến các khu vực đại dương của Tasmania, Nam Úc, Alaska, quần đảo Aleutian,một phần của châu Âu, và Maine.[1]
Bài viết về chủ đề sinh học này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Asterias amurensis, còn được gọi là Sao biển Bắc Thái Bình Dương, là một loài sao biển có nguồng gốc ở bờ biển phía bắc Trung Quốc, Hàn Quốc, Nga và Nhật Bản. Loài này đã được giới thiệu đến các khu vực đại dương của Tasmania, Nam Úc, Alaska, quần đảo Aleutian,một phần của châu Âu, và Maine.
Asterias amurensis Lütken, 1871
Амурская морская звезда[1] (лат. Asterias amurensis) — вид морских звезд из отряда Forcipulatida.
Имеет пять лучей, спинная сторона выпуклая, её цвет синий, сиреневый или красноватый, брюшная сторона плоская, бледно-жёлтая. Диаметр до 30 см.
Населяет северную часть Тихого океана. В российских водах многочисленна в Японском море, Татарском проливе, у берегов южной части Сахалина и на юге Курильской гряды. Населяет глубины от 50—60 метров до прибрежной полосы.
Кормится двустворчатыми моллюсками (мидиями, морскими гребешками).
Нерестится два раза в год — в мае—июне и августе—сентябре. Одна особь вымётывает в среднем 12 миллионов икринок, из которых развиваются двусторонне-симметричные личинки бипиннарии, а затем брахиолярии. Личинки питаются микроводорослями.
Обладает ядовитыми свойствами и способна вызвать отравление при употреблении в пищу.
Вредитель марикультурных хозяйств. На стадии личинки она способна проникать в садки даже с мелкой сеткой.
Амурская морская звезда (лат. Asterias amurensis) — вид морских звезд из отряда Forcipulatida.
多棘海盤車（學名：Asterias amurensis）是一種原産於中國、日本、韓國和俄羅斯沿岸的海星。[1] 後來被船隻攜帶，引入了塔斯馬尼亞島、阿拉斯加、歐洲和緬因州附近海域。[1] 在許多地區它都是入侵物種，更是世界百大外來入侵種之一。[2]
多棘海盤車對入侵地的生態和經濟都有重大影響，它既捕食幼年雙殼綱生物從而對當地經濟捕撈產生影響，也造成了一些瀕危物種的數量衰退。[3] 即使是在原產地日本，當地海洋養殖業每年也還會花去上百萬美元來控制多棘海盤車的擴張。[3]
多棘海盤車（學名：Asterias amurensis）是一種原産於中國、日本、韓國和俄羅斯沿岸的海星。 後來被船隻攜帶，引入了塔斯馬尼亞島、阿拉斯加、歐洲和緬因州附近海域。 在許多地區它都是入侵物種，更是世界百大外來入侵種之一。
多棘海盤車對入侵地的生態和經濟都有重大影響，它既捕食幼年雙殼綱生物從而對當地經濟捕撈產生影響，也造成了一些瀕危物種的數量衰退。 即使是在原產地日本，當地海洋養殖業每年也還會花去上百萬美元來控制多棘海盤車的擴張。
キヒトデ(黄海星、黄人手、学名Asterias amurensis)は、棘皮動物門ヒトデ綱の生物。一般に「ヒトデ」と呼ばれる生物群の中で、日本でもっとも普通に見られる種の一つのため、かつては単にヒトデと呼ばれた。
やや平たい長三角形の腕を、一般的に5本放射状に伸ばすが、個体により4本や6本のものも存在する。体表にはイボ状の棘が密生している。体色は白色から黄色、濃褐色まで個体差が大きい。北太平洋沿岸に広く分布する。近年は船舶のバラスト水により移動し、オーストラリア沿岸にも増殖が認められ、漁業に被害を与えている。肉食であり、魚介類の死骸のほかアサリなどの貝類を捕食する。輻長は大型個体では20cmを超える大型のヒトデである。体内にサポニンを含むため他の生物に捕食されにくい。
キヒトデの腹面
キヒトデの管足
元々の生息地は北太平洋で、日本、中国北部、朝鮮半島からロシアの沿岸。オーストラリア南部にも移入種として分布する。水温7-10℃を好むが、0-25℃に耐えることができる。塩分濃度18.7-41‰、深度220m以浅に生息する[1]。日本では北海道以南の浅海から海岸の岩礁から砂泥底に広く生息する。
有性生殖と分裂による無性生殖を行うことができる。オーストラリアでの有性生殖は6-10月で、雌は2千万個の卵を放出する。孵化した幼生は着底まで120日間のプランクトン生活を過ごす。およそ12か月、直径10cmで性成熟する[1]。
本種の「標準和名」は文献によって「ヒトデ」「キヒトデ」「マヒトデ」などが使用されている場合がある。これは、1980年代頃まではヒトデが本種の和名として使用されていたが、ヒトデ綱の総称としてもしばしば「ヒトデ」（＝ヒトデ類）が使用されて紛らわしいため、発生学者などらによりキヒトデと呼ばれ始め、さらに本種の体色は上記の写真のように黄色とは限らないことからマヒトデが提唱されたという複雑な経緯を持つためである[2]。
日本では、他のヒトデ類とともにホタテガイやアサリなどの漁業資源を捕食する。北海道の厚岸湾でアサリ漁が壊滅的な打撃を受けたのはキヒトデのせいだと考えられている。また、貝や蟹を狙った篭漁でヒトデが大量に混獲されるのも問題である[3]。一部地域で食用にするものの、有用度が低いため廃棄するしかなく、邪魔者として扱われている[4]。
1980年代にオーストラリアのタスマニア島沿岸に定着したキヒトデは、1990年代半ばまでに各地で増殖した[5]。生息場所の蟹、ウニ、ホヤ、他のヒトデを食べて在来種に大打撃を与え、さらに養殖のイガイ、カキ、ホタテガイにも被害を与えた[6]。ニュージーランド政府はオーストラリアからのキヒトデ侵入を警戒してバラスト水排出に規制をかけている[7]。世界の侵略的外来種ワースト100 (IUCN, 2000) 選定種の一つである。
Fphilip V. Mladenov著『海洋生物学 地球を取りまく豊かな海と生態系』、丸善出版、2015年。原著 Marin Biology: A Very Short Introductyion, Oxford University Press, 2013.
