The Northern Pacific seastar (Asterias amurensis) is an invasive species in Australia.
The Northern Pacific seastar (Asterias amurensis) is an invasive species in Australia.
This seastar is native to the coasts of northern China, North Korea, South Korea, Russia and Japan, and distribution of this species into other countries has increased. It is on the Invasive Species Specialist Group list of the world's 100 worst invasive species. They can be transmitted to waters around the world via seawater in live fish trade, via recreational boats, in ballast water, and on the hulls of ships. [1]
The species prefers waters temperatures of 7°C to 10°C, but it has adapted to Australian waters of around 22°C, and usually found in shallow waters of protected coasts. It is able to tolerate a wide range of temperature and salinity, so is frequently found in estuaries and on muddy, sandy or rocky sheltered areas of intertidal zones. [1]
Asterias amurensis was first seen in Tasmanian coastal waters in 1986. [2] Their presence has been recorded in the state from as far north as Banks Strait (between Cape Portland and Clarke Island [3] ) and south to Recherche Bay, with the highest population densities in sheltered waters in south-east Tasmania, particularly the Derwent Estuary. [4]
It then spread northwards, [4] and was detected in Port Philip Bay, Victoria, where it was observed to reach up to 12 million individuals over a two-year span, [1] and is now considered established there. It has also been seen in San Remo, Anderson Inlet, Waratah Bay, Tidal River and the Gippsland Lakes area, but measures are being taken to ensure that they do not get established in these areas. [4]
In Australian waters, spawning occurs between July and October, [1] and the female seastar can carry 10 to 25 million eggs. [4] It is a voracious predator, consuming bivalves, gastropod molluscs, barnacles, crustaceans, sea worms, echinoderms, ascidians, sea urchins, sea squirts and other seastars, including those of its own species if other supplies are exhausted. Its preferred foods are clams, mussels and scallops, but will also eat dead fish and fish waste. [1]
Although the species prefers shallow, sheltered areas, it has also been observed in other habitats, including on rocky reefs and bedrock, and, in its native range around Japan, at depths of up to 200 metres (660 ft). [4]
The Northern Pacific seastar is considered a serious pest of native marine organisms in Australia, and is a major factor in the decline of the critically endangered spotted handfish. It preys on the handfish eggs, and/or on the sea squirts (ascidians) [1] that help to form the substrate that the fish spawn on. [2] It is also considered a mariculture pest, as it settles on the lines used to grow scallops, mussels and oysters, as well as salmon cages. [1]
In 2005, a two-year study identified Asterias amurensis as "one of the ten most damaging potential domestic target species, based on overall impact potential (economic and environmental)", and as having a "reasonably high impact/or invasion potential". [1]
The species is listed on the National Introduced Marine Pest Coordinating System (NIMPIS), [4] a website which provides information on "the biology, ecology and the distribution of marine pests either established or that pose a risk of future introduction to Australia". [5]
A. amurensis is included in Australia’s Priority Marine Pest List, and in 2019 was listed as an Australian pest species of national priority, owing to its impacts on aquaculture, commercial shellfish industries and its impact on the critically endangered spotted handfish (Brachionichthys hirsutus). [4]
The only native species observed to predate on this seastar in the wild in Australia is the native spider crab Leptomithrax gaimardii in the Derwent Estuary. However, laboratory studies showed predation smaller ones by Coscinasterias muricata . This has been viewed as a possible future method of biocontrol of newly-established populations in Victoria. Immersion in freshwater has been shown to kill the larvae, and this is a potential method of control, and commercial harvesting of the animal where populations are established has been mooted, but there are problems associated with this idea, including the lack of a market for the fertiliser produced from them. Other methods considered and/or tried have been dredging, the use of quicklime (calcium oxide) to poison them, netting, trapping and manual removal; however, none of these has proven successful and effective, for a range of reasons. [4] Members of the public are encouraged to report sightings of the animal to the authorities. [6]
Marine biologists hope that diseases or sterile seastars may be introduced in the future. [2]
Volunteer divers have been trying to reduce the Tasmanian population of the seastar in the Derwent River since it became established there. Efforts of this kind in 1993 resulted in the collection of more than 30,000 seastars. [7] However, many of the seastars that were captured were cut up and thrown back into the sea, and it was later found that each part that was thrown back was able to regenerate and grow a new organism, so long as it had part of the central disc remaining. [8]
As of 2021 [update] a new push is being led by local diver Benni Vincent, who intends to organise two to three dives a month over a period of three to five years, concentrating on the areas where the populations are highest, as well as in areas where the handfish live. [2]
The River Derwent is a river located in Tasmania, Australia. It is also known by the palawa kani name timtumili minanya. The river rises in the state's Central Highlands at Lake St Clair, and descends more than 700 metres (2,300 ft) over a distance of more than 200 kilometres (120 mi), flowing through Hobart, the state's capital city, before emptying into Storm Bay and flowing into the Tasman Sea. The banks of the Derwent were once covered by forests and occupied by Aboriginal Tasmanians. European settlers farmed the area and during the 20th century many dams were built on its tributaries for the generation of hydro-electricity.
Asterias is a genus of the Asteriidae family of sea stars. It includes several of the best-known species of sea stars, including the (Atlantic) common starfish, Asterias rubens, and the northern Pacific seastar, Asterias amurensis. The genus contains a total of eight species in all. All species have five arms and are native to shallow oceanic areas of cold to temperate parts of the Holarctic. These starfish have planktonic larvae. Asterias amurensis is an invasive species in Australia and can in some years become a pest in the Japanese mariculture industry.
The Florida Keys National Marine Sanctuary is a U.S. National Marine Sanctuary in the Florida Keys. It includes the Florida Reef, the only barrier coral reef in North America and the third-largest coral barrier reef in the world. It also has extensive mangrove forest and seagrass fields. The Florida Keys National Marine Sanctuary, designated in 1990, is the ninth national marine sanctuary to be established in a system that comprises 13 sanctuaries and two marine national monuments. The Florida Keys National Marine Sanctuary protects approximately 2,900 square nautical miles of coastal and ocean waters from the estuarine waters of south Florida along the Florida Keys archipelago, encompassing more than 1,700 islands, out to the Dry Tortugas National Park, reaching into the Atlantic Ocean, Florida Bay and the Gulf of Mexico.
The spotted handfish is a rare Australian fish in the handfish family, Brachionichthyidae, classified as critically endangered on the IUCN Red List 2020. It has a highly restricted range, being found only in the estuary of Derwent River, Tasmania, and nearby areas, with the main threat to its existence being an invasive species, the Northern Pacific seastar.
Handfish are any anglerfish within the family Brachionichthyidae, a group which comprises five genera and 14 extant species. These benthic marine fish are unusual in the way they propel themselves by walking on the sea floor rather than swimming.
A cryptogenic species is a species whose origins are unknown. The cryptogenic species can be an animal or plant, including other kingdoms or domains, such as fungi, algae, bacteria, or even viruses.
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 formarobusta 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.
Styela clava is a solitary, subtidal ascidian tunicate. It has a variety of common names such as the stalked sea squirt, clubbed tunicate, Asian tunicate, leathery sea squirt, or rough sea squirt. As its common names suggest, S. clava is club-shaped with an elongated oval body and a long peduncle for attaching to a substrate. Although native to the northwestern waters of the Pacific Ocean, since the 1900s, S. clava has become an increasingly successful invasive species outside of its native range. It is edible.
Solaster paxillatus, the orange sun star, is a species of starfish found at varying depths in the northern Pacific Ocean. It is a natural predator of the starfish Asterias amurensis.
The San Francisco Estuary together with the Sacramento–San Joaquin River Delta represents a highly altered ecosystem. The region has been heavily re-engineered to accommodate the needs of water delivery, shipping, agriculture, and most recently, suburban development. These needs have wrought direct changes in the movement of water and the nature of the landscape, and indirect changes from the introduction of non-native species. New species have altered the architecture of the food web as surely as levees have altered the landscape of islands and channels that form the complex system known as the Delta.
Botrylloides violaceus is a colonial ascidian. It is commonly known as the chain tunicate, but has also been called several other common names, including: lined colonial tunicate, orange sheath tunicate, orange tunicate, and violet tunicate. Its native range is in the northwest Pacific from southern China to Japan and Siberia. Colonies grow on solid substrates and consist of individuals arranged in twisting rows. Outside its native range, it is considered an invasive species and is becoming more common in coastal waters of North America and other waters around the world, likely being spread by shipping industries.
Ballast water discharges by ships can have a negative impact on the marine environment. The discharge of ballast water and sediments by ships is governed globally under the Ballast Water Management Convention, since its entry into force in September 2017. It is also controlled through national regulations, which may be separate from the Convention, such as in the United States.
Canadian aquatic invasive species are all forms of life that traditionally has not been native to Canada's waterways. In Eastern Canada, non-native plant and animal species are a concern to biologists. Bringing non-native species such as invasive fishes into Canada can damage the environment and ecosystem by repressing native species due to food competition or preying. Invasive fishes enter the fresh waters of Canada in several ways including drifting, deliberate introduction, accidental release, experimental purposes and, most commonly, through the attachment on international boat hulls. Invasive species are the second biggest threat to fish and other marine life in Canada behind loss of habitat and degradation. The threat to native species is primarily caused by impacts on the food web; however, invasive species also bring dangerous pathogens and physically interfere with existing aquatic life. Invasive species include sea lampreys, zebra mussels, smallmouth bass, European green crab, vase tunicate, and sea squirts.
Didemnum vexillum is a species of colonial tunicate in the family Didemnidae. It is commonly called sea vomit, marine vomit, pancake batter tunicate, or carpet sea squirt. It is thought to be native to Japan, but it has been reported as an invasive species in a number of places in Europe, North America and New Zealand. It is sometimes given the nickname "D. vex" because of the vexing way in which it dominates marine ecosystems when introduced into new locations, however the species epithet vexillum actually derives from the Latin word for flag, and the species was so named because of the way colonies' long tendrils appear to wave in the water like a flag.
Ciona savignyi is a marine animal sometimes known as the Pacific transparent sea squirt or solitary sea squirt. It is a species of tunicates in the family Cionidae. It is found in shallow waters around Japan and has spread to the west coast of North America where it is regarded as an invasive species.
Arcuatula senhousia, commonly known as the Asian date mussel, Asian mussel or bag mussel, is a small saltwater mussel, a marine bivalve mollusk species in the family Mytilidae, the mussels. Other common names for this species include: the Japanese mussel, Senhouse's mussel, the green mussel, and the green bagmussel. It is harvested for human consumption in China.
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Nutgrove Beach is a popular beach destination along the River Derwent in Sandy Bay, Hobart, Tasmania. The north facing beach has views of kunanyi / Mount Wellington, Lords Beach, Wrest Point Hotel Casino, the Tasman Bridge, and the City of Clarence on the eastern shore. Nutgrove Beach neighbours Long Beach and Red Chapel Beach, and is within close proximity to the Sandy Bay Sailing Club and Lower Sandy Bay shops. The beach is dog-friendly and has bathroom facilities.
Taroona Beach is a popular beach destination along the River Derwent in Taroona, Hobart, Tasmania. The south facing beach looks directly out to Storm Bay and the Tasman Sea, with views of the Derwent estuary, the City of Clarence on the eastern shore, Opossum Bay, South Arm, the Alum Cliffs and northern tip of Bruny Island. Taroona Beach is situated between Hinsby Beach and Crayfish Point, home of the Fisheries and Aquaculture Centre for the Institute for Marine and Antarctic Studies. Taroona Beach contains a boat ramp and is backed by Taroona Park which contains bathroom facilities, a skate park, scout hall, the Taroona Tennis Club, and the Taroona Bowls and Community Club.