The Incredible Leafy Seadragon
By Don Silcock
The great brown land down-under is home to many iconic and often strange looking creatures both above and below the water, but few are as unique and visually spectacular as the leafy seadragon!
Known colloquially as “leafies”, but more correctly as Glauert’s seadragon, they are endemic to the southern and western coasts of Australia but are mainly associated with South Australia where they have been adopted as the state’s marine emblem.
Timid creatures that grow to between 20 and 24 cm in length, they use their ornate leaf-like appendages as incredibly effective camouflage to blend in with their surroundings and become almost invisible to the untrained eye.
Belonging to the same family as seahorses and pipefish, Australian leafy seadragons are generally brown to yellow in body color, while their spectacular appendages are typically olive-tinted.
Leafies can also change their coloration as they need to, such as when they are in open water and take on the appearance of floating seaweed!
Habitat and Lifestyle
Leafy seadragons are most commonly found among patches of kelp and seaweed, usually in sandy areas and at depths of less than 30m, living a mainly solitary existence with a lifecycle of between 5 to 7 years.
Formerly it was believed that leafies stay in a specific habitat throughout that lifespan. However recent research has shown that occasionally they will migrate up to several hundred meters away from their primary locations, but seem to have a keen sense of direction and are able to navigate back to their primary spots again.
Their kelp and seaweed habitats provide ample supplies of small crustaceans such as sea lice, plankton and larval fish, which they suck up through their long, pipe-like snouts.
Leafy seadragons do not appear to have any specific predators – perhaps the ultimate compliment to their amazing camouflage!
Like all bony fish, leafies use their swim bladders to maintain position in the water column, while two small fins - one on their back close to the tail, provides forward movement while a second on the ridge of the neck allows them to steer and turn their bodies to change direction.
Although the incredible leaf-like appendages look like some form of fin, they actually play no part in how leafies move through the water and are simply there for camouflage.
The overall effect being that leafy seadragons seem to float majestically through the water!
The leafy seadragon breeding season is during the warmer months of the southern hemisphere, starting late in the Australian spring around October and ending in late February as the summer comes to a close.
It is all temperature dependent and triggered by warmer coastal water, but when it happens the males give up their solitary lifestyle to court the females and when mating occurs, the females deposit between 250 to 300 bright-pink eggs onto the spongy “brood patch” on the underside of the male’s tale. The males then incubate the eggs, carrying them for between 6-8 weeks until they are ready to hatch and change color from pink to purple or orange.
The eggs hatch at a rate of 2 to 3 at a time and the male assists the hatching by shaking his tail and rubbing it up against seaweed and rocks – a process that typically takes many hours.
When they emerge from their eggs the young seadragons are between 4 and 7mm in length and completely on their own, surviving initially by living off the still-attached egg capsule until their snouts are developed enough to start hunting. leafies are fully grown after about two years and ready to mate, but it is estimated that only about 5% of the hatchlings survive to reach that stage of maturity.
Threats to Survival
There are two main threats to the survival of leafy seadragons - bad weather and rogue divers poaching them for the aquarium trade and private collectors!
Unlike their cousins the seahorse, leafies have no tail and therefore no way to attach themselves to the kelp and seaweed in their habitats, so harsh weather conditions and the inevitable big waves, can sweep them from their safe havens and wash them up on the shore.
While storms and big seas are part of nature and, as such, are factored into the overall ebb and flow of the leafy seadragon reproductive cycle there is no doubt that global warming induced changes to Australian weather patterns are impacting these delicate creatures.
However, the bigger threat is the insidious practice of poaching leafies for the aquarium trade where their superb presence in the water makes them so highly prized they are believed to fetch prices of up to $15,000!
Poaching had such a dramatic impact on the overall numbers of leafy seadragons that by the early 1990’s they had been formally protected in the states of South Australia, Victoria, and Western Australia. Plus, by the end of that decade, they were provided with national protection by the Australian Government.
But… despite those actions, the leafy Seadragon has been classified as “Near Threatened” by the IUCN since 2006 and anecdotal indications by experienced South Australian divers is that before poaching really became bad it was quite common to see up to 30 leafies at the most popular sites.
These days it’s a good day if 5 are encountered and so there is clearly a long way to go before these iconic creatures are restored to their former status!
Where to See the Australian leafy seadragon
The jetties and bays of South Australia, plus the state’s very scenic Kangaroo Island are the best places to see leafies – with Rapid Bay, Victor Harbor and Edithburg probably the best locations.
Both Rapid Bay and Victor Harbor are about 85km south of the state capital Adelaide and are very popular dive sites, while Edithburg is on the south-east corner of the Yorke Peninsula and about 50km west of Adelaide across the Gulf St Vincent but some 225 km away by road.
All three are shore dives with easy access in good weather and I have personally had the most success at Edithburg, although I must say that I was guided and doubt I would have been able to find them on my own.
How to See the Australian leafy seadragon
Because the leafy seadragon’s camouflage is so effective they are surprisingly difficult to spot, even when they are right in front of you, so unless you have unlimited time, patience and a particularly strong sense of humor – you will probably be best served by using a guide.
Several years ago, the choices for guides were quite limited, but these days a quick check with Dr. Google shows that a lot of dive shops and various individuals offer “leafy seadragon tours”.
leafy seadragon Etiquette…
Leafies are very delicate creatures that are very territorial and easily stressed, so great care is needed when interacting with them – particularly if the males are carrying eggs! Under no circumstances should they be moved up and down in the water column because their swim bladders are easily damaged by sudden changes in pressure.
Similarly, leafies do not have any eyelids and are believed to quite sensitive to bright light and therefore should not be exposed to video lights over an extended period or excessive use of strobes.
Overall the leafy seadragon is an impressive example of Australian marine biodiversity and encounters with them are truly memorable, but they must be respected and treated with great care!
About the author:
Don Silcock is based in Bali, Indonesia and has dived extensively in Papua New Guinea, Indonesia and many other countries in the Indo-Pacific region. His website is full of information on those locations.