Estuarine Stonefish

The Estuarine Stonefish, Synanceia horrida, has a formidable reputation of being the most venomous fish in the world, it also has a suitably menacing visage to go with its Latin name “horrida”. They have a large head with protruding eyes and mouth, they also have sunken cheeks giving them a skeletal appearance. Their mottled bumpy skin can change color to blend into their surroundings and allow them to disappear when hunting their prey or when hiding from predators. The mucus on their skin and their sedentary ambush behavior encourages algae to grow all over their body, further enhancing their camouflage.

In Australia “Horrida”, which can grow up to 60cm in length, generally inhabit coastal reefs, lagoons and estuaries along the northern reaches of the continent. They make depressions in the mud, sand or loose coralline gravel by digging with their large pectoral fins. “Horrida” lies motionless in the mud during the day, waiting to ambush small fish and crustaceans that wander into their reach. When their prey gets quite close, “Horrida” snap open their mouth and lunge forward in a fraction of a second, engulfing their hapless victim. “Horrida” is reputed to have one of the fastest attacks in the animal kingdom.

Unlike reptiles, insects and arachnids, which use their venom for offensive purposes, “Horrida” only use their venom as a defensive tool. “Horrida” cannot readily escape their predators, as they are relatively poor swimmers. So they have to rely on camouflage and the strong deterrent of their venom to get themselves out of tricky situations. Like most Venomous marine animals, they are very reluctant to use their venom as it is one of their only forms of defence. Once used it takes some time to regenerate so they must use it sparingly.

When Humans and “Horrida” interact it is usually a negative experience for one or the other. If you happen to stumble upon one in the wild, please respect it and keep a good distance away. The last thing you want to do is to scare one into a defensive frame of mind. The sting from “Horrida” is instantly incredibly painful, radiating up the affected limb. The pain is always associated with rapid swelling and sometimes necrosis at the sting site. The toxin can damage muscle in the immediate area and go on to affect the heart and respiratory system. The sting can cause death in extreme cases.

The best way to deal with a sting is immediate first aid. Stay calm and still, immerse the injured area in hot water (test it with a non-affected limb first, as the toxin numbs the affected area you may further injure yourself with a burn) this will dull the pain. Always go to the hospital to be treated with anti-venin. On the other side of the coin “Horrida” are caught and sold for their meat in Hong Kong, and made into “okoze” sashimi in Japan.

Here at Sydney Aquarium, I have gotten to know our resident “Horrida” “Stoney” over many years. I must say I have grown to see the nicer side of him through many great positive interactions. I still always chuckle to myself when I feel the jolt of surprise as “Stoney” snatches the fish or prawn I am offering him from the end of the feeding stick. He’s so quick that in ten years I can’t really say I have ever seen him actually take it. All I can say is it was there in front of his mouth then it was gone.

🙂

One of our dugongs munches on lettuce

For years I have been working with animals and always tried to explain to questioning family and friends the fact that there is so much more to looking after animals than the obvious cleaning up after them. Well, now even that is much more interesting than you would think. Sydney Aquarium is lucky enough to be home to 2 adult Dugongs, Pig our male and Wuru our female. Being shy and elusive animals in the wild has meant that dugongs are a very difficult species to study. As a result, easier and less invasive methods have had to be developed to tell us what is happening with these animals.

There is very little information on the wild reproductive behaviour of dugongs and the little information collected over the years has only ever given a snapshot of one animal at one moment in time. Just like in humans, male and female dugongs produce the same hormones, particularly testosterone, oestrogen and progesterone. These hormones change depending on whether the animal is mature, immature, going through a reproductive cycle or pregnant. Adding to the list we also have corticosterone or cortisol, a stress hormone that can also be measured in most animals. These hormones and their changes show up very quickly in blood samples but getting blood from a Dugong is not the easiest thing to do. So how do you monitor breeding cycles in Dugongs? Put quite simply….you collect their poo.

During our regular cleaning dives, divers are on the lookout for a Dugong swimming past taking a nice dump. They have to be quick as some of the fish seem to enjoy the digested lettuce, the main diet of our Dugongs, and getting a fresh sample and knowing who it came from is important. The faeces and dried, bagged, labelled and frozen. Once we have enough bags or there has been some unusual changes in feeding or behaviour between the two Dugongs, we send the samples off to be tested. The samples are dried in an oven (perhaps not the same one you cook your dinner in) and the dry, powdered poo is tested to measure the levels of the different hormones in each sample.

The only thing we need to keep in mind is that a Dugongs digestive system is slow, taking about a week for their food to pass from one end to the other. This also means that the different hormones and the changes will also take longer to show up in the faecal samples than what they would in a blood sample. If the results come back and show a sudden spike in oestrogen in Wuru on a particular date, we need to then look at what happened a week earlier and try to match up any changes we see in feeding, behaviour or interaction between the two Dugongs to the start of her breeding cycle.

Being able to measure hormone levels in the Aquarium’s dugongs over many years, has meant we now have a wide range of hormone levels for a male and female, starting from juveniles, right through to sexually mature animals. Once we can put all of our feeding and behavioural observations together with the actual hormone changes, we can start to predict breeding cycles, know when there will be sudden drops in feeding and know when Pig might be a little more aggressive than usual. Being a species that is rarely kept in captivity (only 6 animals on display around the world) and with so little information known about them, most of what we are experiencing with our animals is providing new information about this fascinating species. This information can then be applied to behavioural studies of wild populations of Dugongs, enhancing the little information about reproductive behaviour that exists, and potentially aiding in conservation efforts, as Dugong numbers are in decline worldwide.

Andrew 🙂

When people think about aquatic animals, the first things that come to mind are big sharks, coral reefs and brightly coloured fish like Nemo or Dory. Few people actually spare a thought for the aquatic life in our Australian freshwater environments. It’s not that surprising, Australia is well known for its harsh environmental conditions and its long drought periods, neither of which you would associate with lush aquatic life. However, Australia has quite a large range of freshwater fauna- fish, turtles, semi-aquatic lizards and crayfish. In fact there are just as many native crayfish species as there are native freshwater fish species in Australia. The largest of all these to inhabit the mainland of Australia is the Murray River Crayfish (Euastacus armatus). This particular species is the second largest species of freshwater crayfish in the whole world….and I personally think, the most spectacular.

The Murray Cray is also often called a ‘Spiny Cray’ or a ‘Murray River Crayfish’ and in some parts of Australia, it’s simply called a ‘lobster’. This particular species is olive green to black in body colour and identified by their large, strong white pincers (chelae). In small individuals, the chelae are green to yellow. The body, tail and chelae are all covered in short white robust spikes. It’s probably the most heavily armoured of all Euastacus species. It can grow over 2.5kg with the carapace reaching over 17cm, but are commonly seen at 9cm to 13cm carapace. Occasionally a specimen over 3kg is caught, that’s a big cray!

The Murray Cray is freshwater and endemic to Australia. Like the name suggests, it is found in the Murray Darling River as well as the Murrumbidgee River and its tributaries. This particular cray has quite a large geographical range. It is known to occupy the warmer, lower levels of the Murray Darling Basin although they do prefer the cooler, faster flowing parts of the main river. The Murray Cray can live at altitudes from close to sea level to 700m above sea level. Many crayfish, including this one, create extensive burrows in which they live. These burrows are found in or connected to open waters or the water table and are constructed in soft stream banks.

Once upon a time individuals caught in the Murray River may have been as old as 50 years. It is highly unlikely that with the pressure of fishing, they are now able to reach this age. Sexual maturity is not reached until individuals get to 15-20cm long which is around 6 to 9 years old. Often males reach maturity sooner and at a smaller size. When sexual maturity is reached, females lay between 600-1000 eggs. There appears to be a relationship between the number of eggs carried and the size of the female; the lager the female, the more eggs that are likely to be carried. Breeding for these crustaceans will take place from late autumn to early winter. The mother will carry them around in her tail until October. During this time, females tend to hide and may lie on their back to ‘fan’ their eggs. Once the eggs have hatched, they remain attached to the female until they moult 3 times and reach their adult state (see image below).

The Murray Cray is an opportunistic omnivore. They eat loads of detritus, rotting or decaying plant and animal matter but are also considered to be active hunters. Here at Sydney Aquarium, the Murray Cray if fed a variety of foods. Just like us, animals need to keep their diet varied to ensure they get all the nutrients they need to stay healthy. Our cray gets fed white bait for a strong healthy shell (carapace), as well as bits of carrot, mussels and also black worms. In an attempt to keep her happy and occupied, I try to hide her food in different spots so she has to seek it out. However, it never takes her too long to locate the food source, especially if she is hungry.

Being a crustacean, crayfish must from time to time moult. The frequency of moults that occur in a year will determine its age. The younger the crayfish, the more frequent the moulting process. For example, younger adults will moult 4 to 5 times a year, older individuals once or twice a year.

Every morning when I head over to the freshwater section I am always keen to see what our crayfish is doing and what she has been up to overnight. I forgot to mention that they are most active at night. Quite often she will excavate a new section of the tank to make a nice new home for herself. She is quite strong and it doesn’t take much effort for her to turn the tank into a mess. Some mornings I find myself spending a large portion of time fixing things she has moved, or airlines she has destroyed.

A lid was constructed for her tank because on the odd occasion she has escaped from her exhibit and been found crawling around on the floor (to the surprise of myself and other Aquarists). Being the curious creature she is and a great climber, she liked to explore the world outside her tank. Having a hard shell however and the floor being some distance from the tank, there was concern that she may crack her shell and hurt herself on the way down. Getting her back into the tank always had its challenges. She always put up a good fight, pincers ready to grab anything that came near her. Most of the time, I would lose a net or two in my attempt to get her back in.

The main threat for these crays is over fishing. As a result, there are now restrictions in place for recreational fishers, all of which vary from state to state. In New South Wales, restrictions include size and bag limit as well as taking crayfish with ‘berries’ (berries is the term used for a crustaceans carrying eggs). Added to this is a limited season in which you can collect them (start of May to end of August). The Murray Cray is considered vulnerable in the ACT and endangered in South Australia.

Amanda 🙂

Sydney Aquarium's Little Penguins having a nibble.

Little Penguins are the smallest of the 17 penguin species found throughout the world. They stand at only 30cm tall and weigh only 1kg when fully grown, compared to their largest Antarctic cousin, the Emperor Penguin which stands up to 120cm tall and can weigh 40kg.

The name “Little Penguins” is now used instead of “Fairy Penguins” as it is a more accurate translation of their scientific name “Eudyptula minor”

These flightless seabirds are superbly adapted to the marine environment with a streamlined body shape Little Penguins experience the least resistance while swimming underwater. Their wings have evolved into flippers with which they propel themselves through the water, while on land they can be seen standing upright, waddling on their very short legs. The legs are also used while swimming underwater to steer

The dark feathers on Little Penguins are a rich dark blue not black like other penguins, and white on the underside and throat. This type of colouration is called countershading and is a form of camouflage. When seen from above, the penguin would be hard to see against the dark ocean while when seen from below, the white feathers blend in with the bright sky.

Little Penguins have an average life expectancy of 6 or 7 years, although some have been known to survive for 20 years. Here at Sydney Aquarium the ages of our penguins range from 5 weeks to 13 years. The penguin exhibit opened at the aquarium in 1997 with only 4 birds and now has a healthy colony of 12 penguins.

Little Penguins are found along the southern coast of Australia from Fremantle to northern New South Wales and New Zealand. They use to be fairly common on the Australian mainland, but these days due to humans and introduced animals their colonies are generally restricted to offshore islands.

Sydney is lucky to have a colony of Little Penguins in the harbour. The population once numbered in the hundreds but these days the number has decreased to about 60 breeding pairs. This population is the only breeding colony on the NSW mainland.

One of the largest known breeding colonies of Little Penguins can be found on Penguin Island in Western Australia with an estimated 1200 penguins and 500 to 700 breeding pairs.

Penguins are found only in the southern hemisphere so you will never see a penguin and a Polar Bear together in the wild.

The Little Penguins here at Sydney Aquarium dine primarily on fish such as pilchards and are fed at least twice a day. During the breeding season when our parent birds have chicks to raise this can be increased to 3 feeds.

In the wild Little Penguins feed by hunting fish, squid and other small sea animals, for which they travel and dive quite extensively. On average they dive no deeper than 2m and no longer than 20 seconds yet they are able to dive much deeper down to 60m and remain underwater for as long as 90 seconds.

Little Penguins may swim 15 to 30km a day searching for small fish to eat with studies recording one penguin travelling 100km in one day, but during breeding season they generally feed within 15km of the nesting site.

Little Penguins reach sexual maturity at the age of three to four years. They are monogamous and remain faithful to their partner over successive years though they will find another mate if their current one dies. They also tend to return to their nesting site where they hatched and continue to do so over successive years to breed.

Little Penguins usually nest in burrows and often set up their colonies in sand dune vegetation, among rocks and in caves. In Australia, the strongest colonies are on cat-free and fox-free islands.

The breeding season for Little Penguins usually starts between June and September when they lay one or more clutches of two eggs. Both parents sit on the eggs over a period of five weeks after which two chicks often hatch, but usually only one is raised unless food is abundant. For the first 15 days of its life, one parent will remain with the young chick while the other goes in search of food. After this, the chick is left alone while both parents go fishing. Chicks leave the nest to go to sea once they reach the age of 8 or 9 weeks.

Since 1997 Sydney Aquarium has successfully breed and raised over 45 Little Penguins. Some of these have been used to boost the current population while others have been moved to other institutions as part of a breeding program.

In 1996 Sydney Aquarium was involved in a Little Penguin Breed and Release Program with NSW National Parks and Wildlife. This involved the release of five penguin chicks, bred at the Aquarium, into the Sydney Harbour colony, with their establishment in the colony still being monitored.

Sadly a penguins’ greatest threat is humans. Their numbers have declined since European settlement. They die from our discarded plastic rubbish and fishing line, oil spills, cars and boat strikes. Other impacts include people trampling their nest sites, loss of suitable habitat and destabilisation of fore dunes (which may prevent penguins from accessing nest sites).

On land introduced animals such as foxes, cats and dogs have had a severe impact on birds nesting on the mainland and colonies are now largely confined to offshore islands.

At sea their are many dangers for Little Penguins such as natural predators like sea lions, sharks and birds of prey too rough weather and fish shortages.

Lastly, some important penguin facts…

WHAT DO PENGUINS HAVE FOR LUNCH?   “ICEBURGERS”

WHAT DO YOU CALL A PENGUIN IN THE DESERT?   “LOST”

WHAT KIND OF FISH DO PENGUINS CATCH AT NIGHT?   “STARFISH”

🙂

Sydney Aquarium's Blue Ringed Octopus

Sydney Aquarium currently houses the world’s most venomous octopus – the blue ringed octopus.

There are thought to be four species of Blue ringed octopus, three of which are found in Australian waters. The octopus on display is Hapalochlaena fasciata, and occurs in shallow waters from southern Queensland to southern New South Wales. This species can be found in Sydney harbour. Blue ringed octopus can be found amongst rocks, crevices and rockpools of sheltered inshore areas. They occupy the intertidal zone down to depths of 30 meters.

Blue ringed octopuses are a mottled yellowish-brown colour with dark brown bands and irregular faint blue circles and lines across the body. When threatened, these lines and rings become a vibrant blue colour.

Blue ringed octopuses are very small – rarely exceeding 15cm across outspread tentacles, and have a very short lifecycle. They reach maturity at four months of age, and generally live for only 1-1.5 years.

Blue ringed octopuses are very shy and are masters of camouflage. They generally will be found in small crevices, in shells, and underneath rocks in loose sand and rubble. They are able to change the colour and texture of their skin to match their surrounding environment exactly. This makes this animal extremely hard to find in the wild, and quite hard to spot on display here at the aquarium sometimes!

Venom

Blue ringed octopuses have powerful venom used for defense and for capturing prey. They feed primarily on small crabs, and occasionally on small fish and shrimp. The mouth of the octopus contains a beak like jaw. Prey is bitten, and the venom enters the wound as saliva, rather than being injected. The venom can also be released into the water around the prey item, paralyzing the prey.

The venom contains a neurotoxin called tetrodotoxin. This toxin is also found in other animals such as puffer fish, poison arrow frogs, some newts and salamanders, but the blue ringed octopus is the only animal that uses it in the form of venom. Tetrodotoxin is produced by bacteria that live in the salivary glands of the blue ringed octopus.

Tetrodotoxin shuts down signaling in nerves. The toxin interferes with the signals travelling from the brain to the muscles of the diaphragm and the chest wall and leads to respiratory failure. There is little or no effect of tetrodotoxin on the heart or brain.

One bite from a blue ringed octopus reportedly contains enough venom to kill 26 adult people!

Symptoms

People that have been bitten by a blue ringed octopus will feel numbness or tingling around the face and neck within a few minutes. This may be followed by difficulty in seeing, speaking and breathing. Victims may also experience vomiting, abdominal pain, weakness and lack of coordination. This progresses to paralysis which may last from four to twelve hours. If EAR (expired air resuscitation) is not given when breathing difficulty and paralysis begin, the victim will fall unconscious and die from a lack of oxygen to the brain. Death can occur within thirty minutes.

The victim may be completely paralysed and unable to respond, sometimes with fixed dilated pupils, but may still be aware of their surroundings, and have reported that they have been able to hear everything around them.

The symptoms can vary in severity, with children being most at risk because of their small body size. If the victim lives through the first 24 hours they generally go on to make a full recovery with no lasting side effects.

First Aid

Immediately apply a pressure immobilization bandage to the area of the bite. The bite is often painless and may go unnoticed by the victim. Reassure the victim, monitor their breathing and transport the victim to a hospital immediately. Perform mouth to mouth resuscitation if their breathing stops and continue until medical assistance is found. There is no antivenom available for tetrodotoxin.

Safety

The blue ringed octopus is the most venomous octopus in the world. It is a shy animal that only attacks when provoked. It is often found hiding in seashells and in rockpools. If one is found do not attempt to touch or move the animal.

To see our blue ringed octopus here at Sydney Aquarium, look for the wall tanks on the left-hand side, immediately after the Shark Nursery exhibit (formerly the Sydney Harbour tank).

🙂

Ever wondered if there is alien life out there? Well never-mind looking in outer space, we have some of the strangest, weirdest and positively alien creatures living right here on earth! To find them we must journey to inner space, the mysterious ocean world where earth’s very own alien species reside – the Octopus.

Now before you think they are not alien enough for you, let me tell you a little more about them. Firstly, octopus come from a class of animals known as cephalopods, a term formed from two Greek words, which literally means “head” and “foot”. This unusual name tells us about how these animals are constructed, basically with their foot coming straight off their head. Cephalopods include the octopus, squid, cuttlefish and the primitive nautilus.  There are over 700 discovered species of cephalopods living today and they are found in all the world’s oceans, from the tropics to the icy waters of the poles; and from coastal shores to the abyssal depths, some found as deep as 800m!

But of course you need more than that… 

Humans have red blood and all blood is red… right? Wrong, not with the octopus, these little aliens have green blood! The green colour is cause by the copper in their system, which they use instead of iron to aid them in transporting oxygen. Unfortunately copper is not as efficient as iron so the octopus compensates for this, with yet another alien feature – they have 3 hearts. 

Speaking of different colours; cephalopods can change colour faster than any other animal on the planet! With special colour changing cells called chromatophores which are linked to their nervous system, they can pulse and flash colours to confuse prey, dazzle predators and communicate emotions. Strangely, despite their amazing ability to change colour, most cephalopods are colour blind.

Cephalopods can also disappear before your very eyes! Using clouds of black ink and fast jet propulsion, octopus and their cousins can make a quick getaway. Some species even squirt the black ink out in a shape similar to themselves, to distract predators while they escape.

Still not alien enough for you? How about the belief that aliens are intelligent…?

Well, of course, so are our amazing cephalopods. Their intelligence has been the focus of much research over the years they are considered by many scientists to be the smartest invertebrate on the planet.  Octopus have been found capable of learning and have special parts of the brain dedicated to memory. They can solve complex puzzles and some have even puzzled their researchers in return, by creeping out of their tanks at night to steal fish from the adjacent tanks, then sneaking back into their tank to maintain their innocence the next morning. In fact octopus are so clever, they have not only 1 brain – or even 2 which would be amazing – but 9 brains! One central brain and one for each of their tentacles. Some recent research even suggests it may be possible that octopus can dream. Our octopus here at the aquarium has a whole box full of toys or food puzzles to continually challenge his brain, such as a glass jar which he has to learn to open to get his dinner.

Sadly, all these brains are very short lived, with octopus and their relatives living only a few short years. Most cephalopods have a lifespan of only 18 months, a few rare species living a lucky 4 years, but no longer. 

With all this in mind, don’t let all the strangeness of these earthly aliens scare you away from them, for they are one of the most endearing creatures you will ever meet. Each individual has their own unique personality but they are each of them just as loveable as the next.  Okay, so they don’t have fluffy fur, or big round eyes, but to shake hands with an octopus is an unforgettable experience! Whether you be having a water fight, playing tug of war, or just watching their curious antics it is indeed very hard not to love the octopus.  The more you learn about cephalopods, the more wondrous they become.

Behold Zorro – our resident alien

So, aliens on Earth…? You be the judge, come and visit “Zorro” our latest representative of the “other world” here at Sydney Aquarium.

Amy 🙂

Come on, just a bit closer. That’s it, just a little bit more – don’t be scared now.  Yes down here. Just a moment of your time if you would…

Now before rushing off to see all those “big things” – fish, rays, sharks, dugongs, penguins and the host of other much talked about creatures on display at the Sydney Aquarium – I need you to consider me. Why – because whilst I never get put on those glossy posters and fancy adds with the rest of the super cool pin-up crew, I’m still very special in my own way.  I’m “The Caprellid” – hear me roar.

So what is a Caprellid?

We are very small – usually less than 1cm – marine crustaceans (you know like crabs and lobsters). We are typically pale amber or white in colour and found in a diverse range of habitats from shallow estuarine waters as cold as -2 C to the heated waters of deep ocean hydrothermal vents. We spend the majority of our entire life attached to some form of substrate — usually seaweeds and or non-mobile invertebrates such as barnacles and mussels as well as man-made structures such as wharfs, ropes, and nets used in aquaculture.

What do I do?

We have a habit of using our hind legs to cling on whilst our body extends vertically up into the water with our claws spread wide as we bend side to side waving through the water – waiting for some food to drift by – or just chilling out. If I had a willing human available to demonstrate our behavior, I would ask them to stand with a bit of a hunch then hold up both hands and wave them whilst shifting their hips from side to side – sort of like a rhythmically gyrating praying mantis in the groove at Woodstock.

What do I eat?

Well I’m an omnivorous opportunist, meaning that I eat just about anything that passes by and will fit in my mouth, from single celled algae to worms and larval fish. Try as I may though, I just can’t seem to bulk up – hence my nick name “Skeleton Shrimp” – whilst notably unbecoming, truth be known it’s a pretty good description for me.

Who’s looking to eat me?

Unfortunately some fish like to dine on us, but looking at the big picture from a philanthropic perspective this is where we play such a crucial link in the food chain -between those single celled algae and the fish that predate on us.

How do we reproduce?

Many moons ago I found a suitable ladyfriend (Cassie) to mate with – she was gorgeous. We spent countless hours swaying harmoniously in the current together – good times. She told me that she had a perfect brood pouch to hold our fertilized eggs till the day that they would emerge as ready to go mini me’s. However what she was reluctant to tell me was that she also had a bad habit of killing her partner with her venomous claw after mating– needless to say things never worked out between us.

“Good Times” – Ex-girlfriend Cassie (left) and I.

 

Til next you visit….

So next time, like I said before, STOP……Take a closer look, and you might see me or one of my mates just hanging around. Then you’ll be able to yell out to everyone in the aquarium and say: “I know what that is – WOW a Caprellid – how cool. Those show pony sharks and the like have got nothing on this little dude.”

Peace out – The Caprellid

 

Here at Sydney Aquarium, we are lucky enough to be able to house, display and care for some of Australia’s most beautiful and unique aquatic life. Often, when I ask visitors about their favourite animals at the aquarium, it is not uncommon to hear them remarking about some of the larger more ‘impressive’ animals, like the sharks, dugongs and turtles just to name a few. However, today I thought I would draw your attention to one of my favourite animals which calls the aquarium home. Smaller and less-obvious, but definitely an impressive, not to mention beautiful creature…the leafy sea dragon.

The leafy sea dragon is a master of camouflage, so it is no surprise that I often see people staring in to its tank wondering what is inside. It’s not until they take a closer look at the piece of seaweed which floats around the tank, that they realise that they have been looking at the leafy sea dragon the whole time! The sea-dragon’s body is covered in leaf like appendages which have the ability to change colour dependent on the animals age, diet, location and even stress levels. Not only does the leafy sea dragon look like a piece of seaweed, but it also acts like one too. ‘Leafies’ (as they are commonly called) move very slowly and gracefully, gliding and tumbling through the water like a piece of seaweed floating in the current. Their many appendages are used merely for decoration, and their bodies are actually quite rigid. It is a surprise to many people that leafy sea dragons use neither of these things to propel themselves through the water. Leafy sea dragons move around by using translucent fins found on the side of their head and along their spine, which are almost invisible to see, unless you are looking very closely for them.

Leafy sea dragons are one of two species of sea dragon found in Australia, and are found along the coast of Western and South Australia. They grow to around 45cm in length and hide in areas which contain sea grasses and kelp. Leafy sea dragons despite their laid back appearance are fierce predators of larval fish and small crustaceans (amphipods). I often stand and watch fascinated as our leafie swims around its tank sucking up hundreds of mysids one by one.

One of the most interesting things about the leafy sea dragon, is the way in which it reproduces. Like their relatives the sea horses, the males brood and incubate the eggs, and give birth to the young. Female sea dragons will lay around 100-250 eggs on the underside of the males tail, attaching them to an organ known as the brood patch. Here they are provided with oxygen, and left to develop for around 4-6 weeks. These pink eggs will then hatch, and the male sea dragon gives birth to completely independent young. While there are very few (if any) natural predators to an adult leafy sea dragon (due to their outstanding camouflage), only around 5% of the males brood will survive to maturity.

Despite their exceptional ability to hide from predators, leafy sea dragons are listed as a near threatened species. Unfortunately many sea-grass habitats in which they reside are being degraded and destroyed as a result of pollution and excessive run-off from nearby areas. And it is also no surprise that due to their spectacular appearance, leafy sea dragons are often the target of illegal collectors.

If you ever happen to be lucky enough to be diving or snorkelling in areas where leafy sea dragons are found, or even visiting us here at Sydney aquarium, take some time out to slow down and have a good look for these amazing animals. I can guarantee that when you finally spot one you will be captivated by their beauty, and will not be disappointed.

🙂

Many people who walk through the Great Barrier Reef section of Sydney Aquarium have already heard of the symbiotic relationship the “Clownfish” has with the anemone.

The Clownfish picks off any small invertebrates as food that could potential harm the anemone and provides nutrients to the anemone by depositing fecal matter within the anemone. Any normal fish would most likely be stung, but the Clownfish is covered by a mucus membrane that the anemone does not recognize as food, it therefore provides a safe-haven for the Clownfish, protecting it from surrounding predators.

What we might not know is that all Clownfish are born as males, and can later change their sex to female. Generally a group of Clownfish will consist of a “harem”, one large reproductive female and one smaller reproductive male surrounded by even smaller non-reproductive males. If the female dies the reproductive male will change sex and become the female leaving the role of the reproductive, mature male to be taken up by the largest non-reproductive male in the group. A rather, unusual but very successful life strategy, that can be seen here at Sydney Aquarium.

So the answer to the question; Is Nemo a girl or a boy? It would most likely be that Nemo is a boy as he is a juvenile Percula Clownfish (Amphiprion percula). But he has the potential to join a small group of Percula Clownfish and take on the role as the girl or reproductive female.

If you were Nemo what would you do? Remain a boy or become a girl? Next time you make your way down to Sydney Aquarium have a look at our Tropical Marine displays that are home to a variety of different Clownfish, see if you can pick the female from the males.

🙂

The platypus (Ornithorhynchus anatinus) is a very unique animal found only in inland water bodies of eastern Australia.

It is one of three monotremes (egg-laying mammals), the other two being the long-beaked and short-beaked echidnas. With distinctive mammalian traits such as warm bloodedness, the habit of suckling its young with milk and the presence of fur, it also has reptilian traits such as laying eggs. Other interesting features of this amazing animal are its adaptations to its specialised mode of life; the duck-like bill, dorsal nostrils, paddle-like tail and webbed feet.

At Sydney Aquarium, we have 3 female platypus. Their names are Jackie, Nayda and Zoe. Each animal has its own unique behavioural traits. Jackie is recognised for her somersaults, Nayda lounges around inside the pots of plants and Zoe likes a good game of hide and seek. On the underside of their bill is their own unique pattern which stays with them for life, similar to that of a human finger print. These individual traits are all used as forms of identification for the aquarists who look after the animals every day.

The platypus are fed a variety of insect larvae, worms and crustaceans, eating up to a third of their body weight in a day. This would equate to approximately 20 kilos of food/day for an averaged size human. The animals are weighed once/week to monitor any changes in body condition. Handling allows for future veterinary procedures, if required. This ongoing conditioning results in a less stressed animal whenever any handling is required.

Platypus are notoriously secretive, which can make viewing of the platypus difficult in a captive situation. However it is important for all captive animals to have areas for foraging and hiding, similar to that of their natural environment. This assists in the balance of group dynamics by way of providing feeding and resting areas for each animal. Here at the aquarium, our girls have adapted well to their home and as a result can be viewed throughout the day, allowing people a sneak peak at one of Australia’s most secretive and unusual creatures.

Stay tuned for more blogs coming soon!