Damon Mcknight
The Northern Pacific seastar (Asterias amurensis), also known as the Japanese common starfish, is an invasive species in Australia. It was first seen in Tasmanian coastal waters in 1986 and has since been found in various locations across the country, including Port Phillip Bay and Henderson Lagoon in Tasmania. The species is native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, and British Columbia in Canada. The Northern Pacific seastar is a voracious predator that consumes a variety of marine organisms and is considered a serious pest in Australia, impacting native species and industries such as aquaculture and commercial shellfish.
| Characteristics | Values |
|---|---|
| Native region | Northern China, North Korea, South Korea, Russia, Japan, Alaska, the Aleutian Islands, British Columbia in Canada |
| Australian regions | Derwent Estuary, Port Phillip Bay, Henderson Lagoon in Tasmania, Victoria, NSW |
| Water temperature | 7°C to 10°C (can adapt to 22°C) |
| Habitat | Shallow waters, estuaries, seagrass, mussel beds, rocky reefs, bedrock, kelp forests, mud, sand, pebbles, rock, flotsam, nets, artificial substrates |
| Speed | 20 cm/minute |
| Diet | Bivalves, gastropod molluscs, barnacles, crustaceans, sea worms, echinoderms, ascidians, sea urchins, sea squirts, other seastars, dead fish, fish waste, clams, mussels, scallops |
| Reproduction | Females carry 10-25 million eggs |
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What You'll Learn
- Northern Pacific seastars are invasive in Australia
- They are native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, Canada, and more
- The species was first seen in Tasmania in 1986
- They are considered a serious pest of native marine organisms in Australia
- Northern Pacific seastars are voracious predators
Northern Pacific seastars are invasive in Australia
The Northern Pacific seastar (Asterias amurensis), also known as the Japanese common starfish, is an invasive species in Australia. Native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, the Aleutian Islands, and British Columbia in Canada, the species has been introduced to southern Australia, with a significant population in Tasmania and Victoria.
Northern Pacific seastars are listed as prohibited matter under the NSW Biosecurity Act 2015 due to their impact on native fauna and the environment. They are considered a serious pest of native marine organisms in Australia and are known to prey on bivalves, gastropods, molluscs, barnacles, crustaceans, sea worms, echinoderms, ascidians, sea urchins, sea squirts, and even other seastars. Their preferred foods are clams, mussels, and scallops, but they will also scavenge on dead fish and fish waste.
The species typically inhabits shallow, sheltered waters, including seagrass, mussel beds, artificial structures like marinas and ports, rock pools, and rocky reefs. They are frequently found in estuaries and on muddy, sandy, or rocky sheltered areas of intertidal zones. Northern Pacific seastars can tolerate a wide range of temperatures and salinities, which has contributed to their success in Australian waters.
The introduction of Northern Pacific seastars in Australia is believed to be primarily through the transport of free-swimming larvae in ballast water for ships. The larvae are sucked in with the water in one port, such as those in Japan, and then released in another port, such as those in Tasmania. The seastars have also been transmitted via seawater in the live fish trade, recreational boats, and on the hulls of ships.
The invasion of Northern Pacific seastars poses a significant threat to native species in Australia. In Tasmania, they have been linked to the decline of the critically endangered spotted handfish, as they prey on both the handfish eggs and the sea squirts that form the substrate for the fish to spawn. Efforts to control the seastar population in Tasmania, such as physical removal and volunteer collection, have been ongoing but challenging, as even small parts of the cut-up seastars can regenerate into new organisms if the central disc remains intact.
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They are native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, Canada, and more
The Northern Pacific seastar (Asterias amurensis), also known as the Japanese common starfish, is a species native to the coasts of several East Asian and North American countries. Its native range includes the coastal waters of northern China, North Korea, South Korea, far eastern Russia, Japan, Alaska, the Aleutian Islands, and British Columbia in Canada.
In Japan, the Northern Pacific seastar is found on both coasts, from Hokkaido to northern Kyushu, and in the Seto Inland Sea. It is abundant at a depth of 20 metres, but its population decreases at 50 metres, where it is replaced by another seastar species, Distolasterias nipon. The species is also found in the Peter the Great Gulf in Primorsky Krai, in the Chukotka Autonomous Okru in the eastern Chukchi Sea, and in the Kamchatka and Kuril Islands of Russia.
In South Korea, the Northern Pacific seastar is found on both the Pacific and the Sea of Japan coasts, including Dokdo, Geoje Island, Jangmok, and Tongyeong. The species was also collected in British Columbia, Canada, in 1887, northeast of Vancouver Island, although records from Canada and Alaska may represent accidental human introductions.
The Northern Pacific seastar typically preys on large bivalve molluscs and, in turn, is preyed upon by other species of starfish. It prefers shallow sheltered areas and is often found in estuaries and bays. The species can tolerate a wide range of temperatures and salinities and can survive in a temperature range of 0–25°C, with an optimum range of 7–10°C.
While native to East Asia and parts of North America, the Northern Pacific seastar has become an invasive species in Australia, where it was first observed in Tasmanian coastal waters in 1986. It has since colonised waters in the Derwent Estuary, Port Phillip Bay, and Henderson Lagoon in Tasmania, impacting native species such as the critically endangered spotted handfish.
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The species was first seen in Tasmania in 1986
The Northern Pacific seastar (Asterias amurensis), also known as the Japanese common starfish, is an invasive species in Australia. It was first seen in Tasmanian coastal waters in 1986. The species is native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, the Aleutian Islands, and British Columbia in Canada. It has colonised Australian waters in the Derwent Estuary, Port Phillip Bay, and Henderson Lagoon in Tasmania.
The Northern Pacific seastar is a voracious predator that consumes bivalves, gastropod molluscs, barnacles, crustaceans, sea worms, echinoderms, ascidians, sea urchins, sea squirts, and other seastars, including those of its own species. Its preferred foods are clams, mussels, and scallops, but it will also eat dead fish and fish waste. The species is a serious pest of native marine organisms in Australia and is listed as a pest species of national priority due to its impacts on aquaculture, commercial shellfish industries, and the critically endangered spotted handfish.
In Tasmania, volunteer divers have been working to reduce the seastar population in the Derwent River since it became established there. Efforts in 1993 resulted in the collection of more than 30,000 seastars. However, many of the captured seastars were cut up and thrown back into the sea, and it was later discovered that each remaining part was able to regenerate and grow into a new organism as long as it had a portion of the central disc intact.
The Northern Pacific seastar is currently listed as prohibited matter under the NSW Biosecurity Act 2015. It is considered a major threat to native fauna and the environment in Australia and is the subject of ongoing efforts to control and eradicate it.
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They are considered a serious pest of native marine organisms in Australia
The Northern Pacific seastar (Asterias amurensis) is an invasive species in Australia, native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, the Aleutian Islands, and British Columbia in Canada. It was first seen in Tasmanian coastal waters in 1986 and has since colonised Australian waters in the Derwent Estuary, Port Phillip Bay, and Henderson Lagoon in Tasmania.
In Australia, the Northern Pacific seastar is considered a serious pest of native marine organisms. It is a voracious predator, consuming bivalves, gastropod molluscs, barnacles, crustaceans, sea worms, echinoderms, ascidians, sea urchins, sea squirts, and even other seastars. Its preferred foods are clams, mussels, and scallops, but it will also scavenge dead fish and fish waste. This seastar's predation has been linked to the decline of the critically endangered spotted handfish in Tasmania. It preys on the handfish eggs and the sea squirts (ascidians) that form the substrate for the fish to spawn.
The Northern Pacific seastar's ability to tolerate a wide range of temperatures and salinities has allowed it to invade estuaries and muddy, sandy, or rocky sheltered areas of intertidal zones. It is often found in seagrass, mussel beds, artificial structures like marinas and ports, rock pools, and rocky reefs. The species prefers water temperatures of 7°C to 10°C but has adapted to Australian waters of around 22°C.
Due to its impacts on native species, aquaculture, and commercial shellfish industries, the Northern Pacific seastar is listed as a pest species of national priority in Australia. It is included in Australia's Priority Marine Pest List, and efforts to reduce its population in Tasmania, such as physical removal, have been ongoing. The seastar's larvae are also susceptible to immersion in freshwater, which has been proposed as a potential control method.
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Northern Pacific seastars are voracious predators
The Northern Pacific seastar (Asterias amurensis), also known as the Japanese common starfish, is an invasive species in Australia. It was first seen in Tasmanian coastal waters in 1986 and has since colonised the Derwent Estuary, Port Phillip Bay, and Henderson Lagoon in Tasmania. The Northern Pacific seastar is a voracious predator, consuming a variety of marine organisms, including bivalves, gastropod molluscs, barnacles, crustaceans, sea worms, echinoderms, ascidians, sea urchins, sea squirts, and even other seastars. Its preferred foods are clams, mussels, and scallops, but it will also scavenge dead fish and fish waste. This seastar is considered a serious pest in Australia, impacting native species, aquaculture, and commercial shellfish industries.
The Northern Pacific seastar is a highly adaptable species, able to tolerate a wide range of temperatures and salinities. It is typically found in shallow, sheltered waters, but has also been observed in other habitats such as rocky reefs, kelp forests, mud, sand, and artificial structures. In its native range in Japan, it has been found at depths of up to 200 meters. The species prefers water temperatures of 7°C to 10°C, but it has successfully adapted to Australian waters, which can reach around 22°C.
The seastar's ability to tolerate a wide range of conditions has contributed to its success as a predator. It is a generalist feeder, able to take advantage of a variety of food sources. Its preferred prey are bivalves, which include clams, mussels, and scallops. By consuming these filter feeders, the seastar reduces competition for resources and increases its own access to food. In addition, the Northern Pacific seastar exhibits cannibalistic behaviour, feeding on other seastars, including those of its own species if other food sources become scarce.
The reproductive strategy of the Northern Pacific seastar further highlights its predatory nature. During spawning season in Australian waters, which occurs between July and October, the female seastar can carry 10 to 25 million eggs. This high reproductive output ensures the survival of at least some individuals, even in the face of predation or other environmental challenges. The seastar's ability to quickly regenerate lost arms, as long as a portion of the central disc remains, also contributes to its resilience and success as a predator.
The Northern Pacific seastar's impact on native species in Australia is significant. It is listed as a pest species of national priority and is considered a major threat to native fauna and the environment. In Tasmania and Victoria, it has been reported to impact native bivalve populations and other small invertebrates. Additionally, the seastar has been implicated in the decline of the critically endangered spotted handfish (Brachionichthys hirsutus). It preys on the handfish eggs and the sea squirts that form the substrate for the fish to spawn, further endangering this already vulnerable species.
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Frequently asked questions
Northern Pacific seastars are found in Tasmania, Victoria, and New South Wales. They have been spotted in the Derwent River, Derwent Estuary, Port Phillip Bay, and Henderson Lagoon in Tasmania. They are also present in the waters of Port Phillip Bay, where they are considered a pest.
No, Northern Pacific seastars are not native to Australia. They are an invasive species that were first seen in Tasmanian coastal waters in 1986. They are native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, the Aleutian Islands, and British Columbia in Canada.
The Northern Pacific seastar is listed as prohibited matter under the NSW Biosecurity Act 2015. It is considered a major threat to native fauna and the environment and is included in Australia's Priority Marine Pest List. Efforts to reduce their population in Tasmania have been made by volunteer divers since they became established in the Derwent River.
