Leslie Massey
Sea stars, also known as starfish, are found in a variety of habitats across Australia, from the intertidal surf beaches of Sydney to the deepest oceans. Sydney is home to a diverse range of echinoderms, with over 120 species, including sea stars. Sea stars are also found in Western Australia, with numerous species present in the state's marine parks. South Australia boasts a range of sea star species, from the tiny one-centimetre stars to large species spanning about 50 cm. The Northern Pacific sea star, a non-native species, has become established in Tasmania and Victoria, posing a significant threat to native marine life.
| Characteristics | Values |
|---|---|
| Location | South Australia, Western Australia, Sydney, Tasmania, Victoria |
| Marine Parks | Montebello Islands Marine Park |
| Species | Biscuit star, Six-armed cushion star, Granular sea star, Northern Pacific seastar, Crown-of-Thorns Starfish, Velvet sea star |
| Habitat | Reefs, seagrass beds, intertidal rocks, intertidal surf beaches, deepest oceans, estuaries, muddy, sandy or rocky sheltered areas of intertidal zones |
| Size | 1 cm to 50 cm across |
| Colour | Dark purple, maroon, orange |
| Diet | Red algae, seaweeds, sponges, sea squirts, worms, bivalves, gastropods, molluscs, clams, mussels, scallops, dead fish, fish waste |
| Behaviour | Carnivorous, scavengers, can regrow limbs |
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What You'll Learn
Sea stars are found in Sydney, New South Wales
Sea stars, also known as starfish, are found in Sydney, New South Wales, Australia. They are a distinctive group of invertebrate animals, often identified by their star-shaped profiles with five or more tapering arms radiating from their central bodies. Some species, however, have a more cushion-like pentagonal shape with reduced arms. Sea stars are classified as echinoderms, which are spiny-skinned marine animals that include sea urchins, feather stars, brittle stars, basket stars, and sea cucumbers.
Sydney is known to have over 120 species of echinoderms, and approximately 30 species of sea stars have been recorded in the region. These sea stars are typically found at depths of up to 30 metres, from Gosford in the north to Bundeena in the south. They are ecologically and commercially significant, as seen by the impact of the invasive Crown-of-Thorns Starfish on the Great Barrier Reef and the introduction of the Northern Pacific Seastar to parts of Australia.
Sea stars in Sydney exhibit basic body symmetry and possess an internal calcareous skeleton and a water vascular system composed of fluid-filled canals. These canals often manifest as external tube feet, which the sea stars use for locomotion. While sea stars share these characteristics, body shape and other features differentiate them into the class Asteroidea.
The Sydney Seastar Project assists in identifying sea stars encountered in the region and provides up-to-date information on the species occurring in the area. This project is a collaborative effort involving institutions such as the Australian Museum in Sydney, the Academy of Natural Sciences in Philadelphia, and the Natural History Museum in London.
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They are also found in Tasmanian coastal waters
Sea stars are found in Tasmanian coastal waters, where they are considered an invasive species. The Asterias amurensis, also known as the Northern Pacific seastar, was first seen in Tasmanian waters in 1986. It is native to the coasts of northern China, North Korea, South Korea, Russia, Japan, Alaska, the Aleutian Islands, and British Columbia in Canada. It is listed as one of the world's 100 worst invasive species and can be transmitted to waters around the world through seawater in the live fish trade, recreational boats, ballast water, and the hulls of ships.
The Northern Pacific seastar is a serious pest of native marine life in Australia and is a major factor in the decline of the critically endangered spotted handfish, as it preys on the handfish eggs. 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. The species is known to have a broad diet and a ravenous appetite, which could force local communities and commercial shellfish in Tasmanian waters to fight for their survival.
In Tasmania, the Northern Pacific seastar was found to prey on the egg masses of the spotted handfish and the ascidians on which they spawn. It is preyed upon by the native spider crab Leptomithrax gaimardii in the Derwent Estuary, and laboratory studies have shown predation by Coscinasterias muricata. The only other known predator of the Northern Pacific seastar is the sunstar Solaster paxillatus, which eats this species in Japan.
Community efforts to reduce the population of the Northern Pacific seastar in Tasmania have been made since it became established in the Derwent River. In 1993, volunteer divers collected over 30,000 seastars, but many of the captured seastars were cut up and thrown back into the sea, where each remaining part was able to regenerate and grow into a new organism. To protect commercial shellfish leases, specially designed traps (made in Tasmania) are used. These traps are similar to lobster traps and are baited with fish scraps, but they are not effective in catching all the seastars in Tasmanian waters.
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They are found in South Australia, in reefs and under intertidal rocks
Sea stars are found in a variety of habitats in Australia, from intertidal surf beaches to the deepest oceans. They are found in South Australia, in reefs and under intertidal rocks. South Australia is home to a variety of sea star species, ranging from one of the smallest species, which grows up to one cm, to large species that span about 50 cm across.
One of the most common sea stars found in South Australia is the biscuit star, which grows to about 10 cm across and has a wide range of colours and patterns. They are found on reefs and other hard surfaces, from the intertidal zone down to depths of about 40 meters. Biscuit stars are often found near sponges and sea squirts, which are their preferred food.
Another sea star species found in South Australia is the six-armed cushion star, which is usually less than 10 cm across and can be found in shallow reefs, seagrass beds, and under intertidal rocks. Its arms are typically coloured dark purple or maroon, with bright orange tube feet. The six-armed cushion star feeds on red algae, small seaweeds that grow on seagrasses, and various invertebrates such as sponges, sea squirts, and worms.
The granular sea star is another species found in South Australia. It is a five-armed, reef-dwelling sea star that grows to about 20 cm across. Granular sea stars have wart-like lumps called tubercles on their arms and feed on sea squirts and bivalve molluscs. Like some other sea stars, they have the ability to drop their arms when stressed and regrow them.
Velvet sea stars, with the scientific name Petricia vernicina, are found across southern and south-eastern Australia, as well as around islands off the eastern coast. They are also known as 'Patrick' by divers, due to their resemblance to the character from SpongeBob SquarePants.
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They are found in Western Australia, in marine parks
Sea stars are found in a range of habitats in Australia, from intertidal surf beaches to the deepest oceans. They are distributed throughout the world's temperate and tropical seas, and this includes Western Australia, where they can be found in marine parks.
Western Australia's marine parks are home to numerous species of sea stars. The Montebello Islands Marine Park, for instance, is home to 170 species of sea stars, as well as sand dollars, heart urchins, and sea cucumbers. Sea stars are common and can breed quickly when conditions are right. However, they have not been extensively studied, and many species in Western Australia's marine parks remain unknown to scientists.
In Western Australia, you can find sea stars in the intertidal zone, on reefs, and under rocks. They can also be found in the waters of the southern and southeastern parts of the country, as well as around islands off the eastern coast. Sydney, in particular, is known for its diverse echinoderm population, with over 120 species.
If you're interested in seeing sea stars in Western Australia's marine parks, you can do so by snorkelling. Remember to handle the sea stars gently and return them to the spot where you found them. It is illegal to collect sea stars from most marine parks in Western Australia, even if they are dead.
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They are found in Victoria, in Port Philip Bay
Sea stars are found in Victoria, in Port Philip Bay. The Northern Pacific seastar, a species native to the coasts of northern China, North Korea, South Korea, Russia, and Japan, has spread to Port Philip Bay, where it is now considered established. It is a voracious predator and scavenger with a prolific reproduction capacity, and its population in the bay numbers in the millions.
The Northern Pacific seastar is a marine pest in Victoria and is considered a serious threat to native marine organisms in Australia. It preys on the eggs of the critically endangered spotted handfish and on the sea squirts (ascidians) that form the substrate that the fish spawn on. The seastar's presence has been recorded in other parts of the state of Victoria, including as far north as Banks Strait and south to Recherche Bay, with the highest population densities in sheltered waters in southeast Tasmania, particularly the Derwent Estuary.
The seastar's introduction to Port Philip Bay is likely due to its spread from Japan, where it is also found. Once in the bay, the seastar benefited from a lack of native predators, with the only known native species to prey on it in the wild in Australia being the spider crab Leptomithrax gaimardii in the Derwent Estuary. Laboratory studies have also shown predation of smaller Northern Pacific seastars by Coscinasterias muricata, indicating a possible method of biocontrol for newly established populations.
The Northern Pacific seastar's rapid reproduction and ability to grow a full body from a single arm contribute to its success in establishing itself in new environments. It is often mistaken for native species, so it is important to be able to distinguish between the two. In addition to its impact on native fish stocks, the seastar's presence can also have economic implications, as it may compete with fisheries for resources.
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Frequently asked questions
Sea stars are found in a variety of habitats across Australia, from intertidal surf beaches to the deepest oceans. They can be found in the Sydney region, in depths of up to 30 meters, and in Western Australia, where numerous species inhabit marine parks. Sea stars are also found in South Australia, with some species growing up to 50 cm across.
Sea stars are often referred to as starfish, but they are not actually fish. Sea stars are echinoderms, which means they have spiny skin and are related to sea urchins, sand dollars, and sea cucumbers.
Yes, sea stars are common in Australia and can be found in many marine environments. Sydney alone has over 120 species of echinoderms, which include sea stars.
Sea stars generally take the shape of a star or pentagon and typically have five arms, although species with six, seven, ten, or more limbs also exist. They vary in size and are often brightly coloured. If you find one while snorkelling, you can pick it up and examine it closely, but be sure to put it back where you found it.
