Weedy sea dragons, also known as common sea dragons, are endemic to the waters off of the southern coast of Australia. Individuals of this species have been sighted off the eastern coast of Australia in New South Wales, as far north as Port Stephens; along the southern coast; and up around the western coast of Australia as far north as Geraldton, West Australia. (Dawson, 1985)
Biogeographic Regions: australian (Native )
Phyllopteryx taeniolatus can be locally common in NSW, VIC and TAS. In Victoria it can often be seen in shallow areas of Port Phillip Bay (surrounded by the city of Melbourne) and Western Port. In NSW it is often found on sheltered reefs in waters exceeding 15 m, but is also found in shallower waters in large open bays (Kuiter 2000a). In TAS large numbers have been observed at a number of sites in the D’Entrecasteaux Channel, particular in the Blackman’s Bay/Kingston area (Martin-Smith and Davey, unpublished data).
Follow the link below for map of the known range of P. taeniolatus.
A weedy sea dragon reaches 45cm in length and has a narrow body with a long, tubular snout. It has two spines above its eye, one spine in front of the eye, and a varying number of leafy appendages, either paired or single, along its body. These purple appendages have a black border, and provide the fish camouflage in its habitat because they resemble floating seaweed. The bodies of these fish are usually red with yellow spots and seven purplish blue stripes near the head. Weedy sea dragons are not sexually dimorphic and have no subspecies, but do have a close relative: Phycodurus eques, the leafy sea dragon. The leafy sea dragon is found in the same geographic range, and differs in appearance only because it has many more appendages. (Scott, 1962)
Other Physical Features: bilateral symmetry
Phyllopteryx taeniolatus can be found in rocky reefs, sea weed beds, sea grass meadows, and kelp gardens. In all of these areas, their leafy appendages provide protection by means of camouflage against the sea weed. While this may seem like a broad range of habitat, sea dragons have very specific requirements. The water must be between 12 and 23 degrees Celsius, and 10-50 meters deep, although they most often are found between 8 and 12 meters deep. (Australian Museum, 1999)
Aquatic Biomes: reef
Habitat and Ecology
The extent to which the species occurs over seagrass meadows is unknown and needs investigation. The other large syngnathid from southern Australian waters, the Leafy Seadragon, was not considered to be associated with seagrass until recently. For that species, ultrasonic tracking of individuals demonstrated that they were at least as likely to occur over seagrass as over algae. Although this may not be true for Weedy Seadragons, it is important to establish any use of seagrass meadows because seagrasses are known to be adversely affected by pollution in southern Australia; habitat use is therefore important in the consideration of potential threats (see Threats, below).
The breeding season for Weedy Seadragons is early summer and there is one brood per season. Males carry the eggs externally below their tail and the skin forms a cup on each egg during deposition. Incubation time is about eight weeks and up to about 250 young hatch. Some individuals mature in one year, but most usually breed in their second year when fully grown (Kuiter 1993). Baker (2000a) reports that brooding males have been observed in NSW from mid-winter to mid-summer, but never from February to June, despite sightings of over 350 seadragons during this period.
In the Sydney area and in southern NSW, aggregations of between 20 and 40 seadragons have been observed, respectively (Baker 2000a).
Phyllopteryx taeniolatus feeds on mysids and other small crustaceans and attains about 45 cm in total length (Kuiter 1993).
Recorded at 50 meters.
Water temperature and chemistry ranges based on 2 samples.
Depth range (m): 0.5 - 78
Temperature range (°C): 16.490 - 18.371
Nitrate (umol/L): 0.171 - 0.347
Salinity (PPS): 35.625 - 36.070
Oxygen (ml/l): 5.271 - 5.446
Phosphate (umol/l): 0.141 - 0.152
Silicate (umol/l): 1.304 - 1.742
Depth range (m): 0.5 - 78
Temperature range (°C): 16.490 - 18.371
Nitrate (umol/L): 0.171 - 0.347
Salinity (PPS): 35.625 - 36.070
Oxygen (ml/l): 5.271 - 5.446
Phosphate (umol/l): 0.141 - 0.152
Silicate (umol/l): 1.304 - 1.742
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Weedy sea dragons have no teeth, but instead feed by way of suction. Their pipe-like terminal mouth has an intricate system of bones pulled by muscles to create a strong suction force that is directed at food. Their prey include mysid shrimp, sea lice, and larval fish. (Scott, 1962)
Life History and Behavior
Perception Channels: tactile ; chemical
While it is not known at what age sea dragons reach sexual maturity, their reproductive strategies are well documented. Like their relatives the sea horses, the male sea dragons brood the eggs. When a male is ready to receive the eggs, which he indicates by wrinkling the lower half of his tail, the female deposits about 250 ruby colored eggs onto his brood patch. The brood patch is made of tiny cups of blood-rich tissue, and each cup holds and nourishes one egg. After eight weeks, the eggs hatch over a period of a couple days. After hatching, the young sea dragons spend two or three days in the yolk sac of the egg, where they continue to be nourished. After the young leave the yolk sac, they feed on copepods and rotifers, although only 60-120 of them will survive, while the others fall prey to sea anemones. The season of breeding is August through March, and during this time the males brood two batches of eggs. The young receive no parental care after they hatch because they are released into the external environment. (Dawson, 1985; Cronulla Dive Center, http://pixie.tig.com.au/~scuba/seadragon.html)
Molecular Biology and Genetics
Statistics of barcoding coverage: Phyllopteryx taeniolatus
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1
Weedy sea dragons are threatened by aquarium collectors and Oriental herbalists, who can sell their dried and powdered bodies for up to $200/gram. They are also killed by pollution and fertilizer run-off in their shallow, coastal habitats. Because of these threats, weedy sea dragons are a legally protected species in both New South Wales and Tasmania. (Australian Museum, 1999)
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: near threatened
IUCN Red List Assessment
Red List Category
Red List Criteria
There is no evidence of changes in population sizes, but its habitat has been adversely affected by pollution. The extent of degradation and loss of habitat has not been measured but, at this stage, probably represents a small proportion of the total extent of habitat available.
Some issues point towards criteria within the Endangered (EN) category, and these points are described below. None of the information provides compelling evidence for trends in occurrence or occupancy.
The extent of occurrence is estimated to be 2,000 km², which is below the 5,000 km² threshold for EN B1 and well below the 20,000 km² threshold for Vulnerable (VU). Total area of occupancy may be less than 2,000 km² (VU B2 threshold) but at this time is unknown. Criterion B2 therefore cannot be used.
Seadragons have been sighted at numerous locations within the range but it is impossible to determine how fragmented occurrence is. Therefore, sub-criterion B1a cannot be used at present.
EN B1b(iii) (continuing decline in area, extent and/or quality of habitat) is met. Seadragon habitats such as algal covered reefs are being adversely affected by human activities and loss in quality and quantity of habitat has been documented (Baker 2003). The threat to habitat is greatest near major urban centres (e.g., Sydney, Perth, Adelaide, Melbourne), where discharge of storm water and treated sewage leads to eutrophication and increased sedimentation. The threat to seadragons is lessened to an extent by the occurrence of seadragons at sites distant from these cities, provided that these areas are biologically connected through movement or dispersal.
In Tasmania, the macroalgae-covered reefs on which seadragons occur face another threat. Over the last 20 years, the sea urchin Centrostephanus rogersii, has become more common and increased its range around the state. The increase in sea urchins is considered to have resulted from harvesting of rock lobster, a known predator of urchins, and climate change. Grazing by urchins reduces the abundance of kelp and other macroalgae through the formation of urchin barrens. Furthermore, significant losses of giant kelp (Macrocystis pyrifera) have been documented over the past 20 years (Edyvane 2003), associated with increased water temperatures. The reduction in macroalgae could adversely affect seadragons although this has not been demonstrated.
In South Australia, a possible contraction in extent of occupancy has been mentioned (Baker 2003). Historical records exist from benthic surveys in Gulf St Vincent in the period 1965–1971, where reportedly “numerous weedies were observed” in northern Gulf St Vincent, adjacent to the city of Adelaide (S. Shepherd, pers. comm. to Baker, 2003). No sightings in this area have been reported to Dragon Search during the late 1990s and early 2000s. Admittedly the lack of recent sightings might be due to the lack of popular diving spots in the northern gulf, and the lack of systematic surveys in recent years (Baker 2003). However, the occurrence of seadragons might have been affected by significant habitat degradation and loss recorded since the 1960s in this part of the gulf. In particular, large areas of seagrass have been lost in waters deeper than 10 m south of a line between Ardrossan and Port Prime (Baker 2003). More rigorous monitoring of seadragon populations would assist in assessing changes in occupancy such as this.
In summary, the lack of trend data means that seadragons cannot be described as meeting any of the threatened categories at present, but it nearly meets Endangered under criterion B (currently only one sub-criterion (B1b(iii)) is met). Therefore it is assessed as NT. The greatest threat is habitat loss but at this stage the loss is limited to regions immediately around large cities, which in Australia are well separated.
Continued monitoring is required to establish population trends. Research is also needed to establish areas of occupancy.
- 1996Data Deficient
From the study by Sanchez-Camara and Booth (2004) near Sydney, NSW, using certain assumptions about the width of transects (recorded as 350 long, and assumed to be approximately 20 m wide), densities averaged 58 fish ha-1 at the 2 sites where most work was done. At a nearby site with fewer fish where less work was done, densities were about a quarter of these estimates. Densities at two sites in the Derwent estuary in TAS have been estimated using mark-recapture methods at 12–20 and 4–10 fish ha-1 (M. Davey and K. Martin-Smith, unpubl. data).
In making an overall population estimate, the following estimations and assumptions were made:
1. The sites at which Sanchez-Camara and Booth (2004) worked were chosen because relatively frequent sightings had been made there previously. An average density across the distribution would be lower, probably lower even than the third site used by Sanchez-Camara and Booth (2004) and the sites in TAS surveyed by Davey and Martin-Smith. A figure of 5 fish ha-1 was used (approximately 10% of upper estimate by Sanchez-Camara and Booth (2004)).
2. The coastline along which Weedy Seadragons occur is an estimated 20,000 km long (including TAS).
3. The species occurs most frequently in a thin strip of shallow water along the coastline, most frequently along the edge of reefs supporting stands of macroalgae. This strip is estimated to be, on average, 100 m wide, giving a total of 200,000 ha of occupancy.
At five fish per ha, the estimated total number of Weedy Seadragons is ~ 1,000,000. Confidence limits cannot be stated but the estimate is clearly based on very loose assumptions. The purpose of making such an estimate is to give perspective to the number of fish that might be removed from the wild (see Threats, below).
Mapping of habitat at sites far from major population centres and research into variability in habitat use at different sites is required to make the estimate of total population size more rigorous.
1. Weedy Seadragons lack a caudal fin and are weak swimmers; in conjunction with a lack of a dispersive egg phase, this potentially makes them vulnerable to habitat loss and degradation, which is the main threat to this species.
2a. Both algae-covered reefs and seagrass meadows have been adversely affected by human activities and loss in quality and quantity of habitat has been documented (Baker 2003). The degradation of habitat is worst near major urban centres (e.g., Sydney, Adelaide, Melbourne, Perth), where discharge of storm water and treated sewage leads to eutrophication and increased sedimentation. Losses of seagrass have been particularly severe along the metropolitan coasts and are well documented (Short and Wyllie-Echeverria 1996). Reefs have been more strongly affected by increased rates of sedimentation resulting from human activities such as sand dredging, land reclamation and coastal urban development (Baker 2003).
2b. Urchin consumption of kelp beds and loss of giant kelp in TAS through climate change.
3. The legal and/or illegal collection of wild specimens has little likelihood of causing long-term changes in population sizes, unless demand increases substantially. The small numbers taken could result in the reduction or loss of groups of animals at particular sites, but this is unlikely to result in measurable effects on populations. Weedy Seadragons have not been reported in surveys of incidental bycatch in trawl fisheries of southeastern Australia.
1. Protected Species in NSW under Fisheries Management Act 1994.
2. The Tasmanian Living Marine Resources Management Act 1995 prohibits the take of all syngnathids in Tasmania (by non-permit holders).
3. Protected Aquatic Biota in Victoria.
4. Subject to Export controls since 1st January 1998, in the Commonwealth Wildlife Protection (Regulation of Exports and Imports) Act 1982.
5. Listed as marine species under s248 of The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
6. No Australian Society for Fish Biology listing.
More information (Source: Martin-Smith et al. 2003)
All Australian pipehorses have been protected in Australian Commonwealth (federal) waters (greater than three nautical miles from the coast) since the beginning of 1998. As most pipehorses are caught in Commonwealth waters they are protected under the Environment Protection and Biodiversity Conservation Act 1999 wherein they are ‘listed marine species’. It is an offence to take, trade, injure or kill listed marine species except under permits issued by the Minister of the Environment. Such permits for exports of syngnathids are issued subject to a management plan, which must be approved by the executive agency, Environment Australia (within the Department of Environment and Heritage). Legal protection is variable for pipehorses caught in Australian State waters (less than three nautical miles from the coast), ranging from full to no protection.
Relevance to Humans and Ecosystems
This peaceful species does not in any way negatively affect the human species.
Members of this species have often been used in Asia as aphrodisiacs and other medicines. Also, many people go scuba diving off the coast of southern Australia specifically to see weedy sea dragons, which, therefore, promote tourism.
Weedy seadragon or common seadragon (Phyllopteryx taeniolatus) is a marine fish related to the seahorse. Adult weedy seadragons are a reddish colour, with yellow and purple markings; they have small leaf-like appendages that resemble kelp fronds providing camouflage and a number of short spines for protection. Males have narrower bodies and are darker than females. Seadragons have a long dorsal fin along the back and small pectoral fins on either side of the neck, which provide balance. Weedy seadragons can reach 45 cm in length.
The weedy seadragon is endemic to Australian waters of the Eastern Indian Ocean and the South Western Pacific Ocean. It can be found approximately between Port Stephens, New South Wales and Geraldton, Western Australia, as well as Tasmania.
The weedy seadragon inhabits coastal waters down to at least 50 m deep. It is associated with rocky reefs, seaweed beds, seagrass meadows and structures colonised by seaweed.
These fish are slow-moving and rely on their camouflage as protection against predation; they drift in the water and with the leaf-like appendages resemble the swaying seaweed of their habitat. They lack a prehensile tail that enables similar species to clasp and anchor themselves.
Individuals are observed either on their own or in pairs; feeding on tiny crustaceans and other zooplankton by sucking prey into their toothless mouths. Like seahorses, seadragon males are the sex that cares for the developing eggs. Females lay around 120 eggs onto the brood patch located on the underside of the males' tail. The eggs are fertilised and carried by the male for around a month before the hatchlings emerge. Seadragons, seahorses and pipefish are among the few known species where the male carries the eggs. The young are independent at birth, beginning to eat shortly after.
Mating in captivity is rare since researchers have yet to understand what biological or environmental factors trigger them to reproduce. In captivity the survival rate for weedy seadragons is about 60%.
The Aquarium of the Pacific in Long Beach, California and the Tennessee Aquarium in Chattanooga, Tennessee in the USA, and the Melbourne Aquarium in Melbourne, Australia are among the few facilities in the world to have successfully bred weedy seadragons in captivity, though others occasionally report egg laying. In March 2012 the Georgia Aquarium in Atlanta, USA, announced a successful breeding event of weedy seadragons. As of July 2012, the Monterey Bay Aquarium has also successfully bred and hatched out baby weedy seadragons on exhibit.
The weedy sea dragon is classified as Near Threatened (NT) on the IUCN Red List 2006. While the weedy sea dragon is a desired species in the international aquarium trade, the volume of wild-caught individuals is small and therefore not currently a major threat. Instead, habitat loss and degradation due to human activities and pollution threaten weedy sea dragons most. The loss of suitable seagrass beds, coupled with natural history traits that make them poor dispersers, put the future of sea dragon populations at risk. This species is not at present a victim of bycatch or a target of trade in Traditional Chinese Medicine, two activities which are currently a threat to many related seahorse and pipefish populations.
It is illegal to take or export these species in most of the states within which they occur. A database of seadragon sightings, known as 'Dragon Search' has been established with support from the Marine and Coastal Community Network (MCCN), Threatened Species Network (TSN) and the Australian Marine Conservation Society (AMCS), which encourages divers to report sightings. Monitoring of populations may provide indications of local water quality and seadragons could also become an important 'flagship' species for the often-overlooked richness of the unique flora and fauna of Australia’s south coast.
The weedy seadragon is in the subfamily Syngnathinae, which contains all pipefish. It is most closely related to the other member of its genus, the ruby seadragon (Phyllopteryx dewysea), and also the leafy seadragon (Phycodurus eques). Haliichthys taeniophorus, sometimes referred to as the "ribboned seadragon" is not closely related (it does not form a true monophyletic clade with weedy and leafy seadragons).
In the November 2006 issue of National Geographic magazine, marine biologist Greg Rouse is reported as investigating the DNA variation of the two seadragon species across their ranges.
This article incorporates text from the ARKive fact-file "Weedy seadragon" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.
- Bray, D.J. 2011, Common Seadragon, Phyllopteryx taeniolatus, in Fishes of Australia, accessed 26 Aug 2014, http://www.fishesofaustralia.net.au/home/species/3127
- "Dragon Search". Dragon Search. Retrieved April 2003.
- "Melbourne Aquarium". Melbourne Aquarium. Retrieved April 2003.
- Dept of Sustainability and Environment Victoria > The marine faunal emblem for the State of Victoria Retrieved 8 August 2011
- Froese, Rainer and Pauly, Daniel, eds. (2014). "Phyllopteryx taeniolatus" in FishBase. November 2014 version.
- "Western Australia Department of Fisheries". Western Australia Department of Fisheries. Retrieved April 2003.
- Morrison, S. & Storrie, A. (1999). Wonders of Western Waters: The Marine Life of South-Western Australia. CALM. p. 68. ISBN 0-7309-6894-4.
- Associated Press (12 June 2008). "Endangered sea dragon at Ga. aquarium pregnant". Newsvine. Retrieved 2 March 2015.
- Papercut Interactive. "Tennessee Aquarium". tnaqua.org.
- Melbourne Aquarium > Conservation Retrieved 6 April 2012.
- "Weedy Seadragons spawn for Hong Kong aquarist". AquaDaily. 2008-07-18. Retrieved 2009-02-01.
- Largest Brood of Weedy Sea Dragons Born at Georgia Aquarium Georgia Aquarium press release, 29 March 2012. Accessed 15 August 2013.
- Weedy Sea Dragons Born At Monterey Bay Aquarium Retrieved 5 August 2012
- "IUCN Red List". IUCN Red List. Retrieved May 2006.
- Martin-Smith, K. & Vincent, A. (2006): Exploitation and trade of Australian seahorses, pipehorses, sea dragons and pipefishes (Family Syngnathidae). Oryx, 40: 141-151.
- "Weedy Seadragon". Zoo Aquarium Association. Retrieved 6 Sep 2012.
- Wilson, N.G. & Rouse, G.W. (2010): Convergent camouflage and the non-monophyly of 'seadragons' (Syngnathidae:Teleostei): suggestions for a revised taxonomy of syngnathids. Zoologica Scripta, 39: 551-558.
- "Rare Ruby Seadragon uncovered in Western Australia". Western Australian Museum. Retrieved 19 February 2015.