Recently, I watched a Painted Dragonet in Bayside fossil beds. Dragonets are in a family of fish that don’t have any scales. Instead, their skin produces a mucous covering. They are also called ‘Stinkfish’ but this belies their beauty. The name was given by fishers, after the fishes’ reaction to being caught, handled and suffocated. Dragonets over-produce the foul-smelling mucous when stressed. Here, I’ll talk a bit more about the more appropriately named and fascinating Painted Dragonets in Port Phillip Bay. Every evening, they transform into the most beautiful fish imagineable.
What Painted Dragonets look like
Painted Dragonets are quite small, generally 7cm or less. They live on the seabed and don’t move like other fish. You’ll often find them by looking out for rapid, inch-like darting movements across the seafloor. They like to hide in plain sight on sand between rocks and rapidly change colour to camouflage themselves against their background. If disturbed, they’ll often duck in under a rock or seaweed, emerging a short time later. On the whole they aren’t that timid, which makes them a nice subject to photograph.
Elsewhere in the world, dragonets are associated with their bright colours and flamboyance and according to the scientists that named them, Painted Dragonets are in a class of their own. Eucallionymus papilio translated is Eu = true; kallion, comparative of kallos = beautiful and papilio = butterfly. This is a beautiful butterfly dragonet. During courtship, the males roll out patterned fins – a behaviour we went to see (see below).
The following gallery shows some of the extraordinary variation in patterning. These were all taken in Bayside. The fish are able to change colour very quickly as they move across the sediment.
Habitat and behaviour of Painted Dragonets in Port Phillip Bay
I find them particularly interesting because of their dependence on specific habitatsWhat is habitat for animals and people? Habitat, hence the word "habitable" describes the natural surroundings in which any animal (or human) lives, that houses basic needs, such as food and shelter. Vegetation, for example, is habitat for animals. On its own, habitat is not necessarily stable or sustainable, which is why it differs from an ecosystem. Habitat in disrepair More in the Bay. By the way, the habitat descriptions across the internet are wrong. They aren’t mostly found in seagrass beds and on soft, muddy areas. Also, they occur right up to the low water mark, sometimes in just a few centimetres of water. Once you know what to look for (and where), they are quite common.
Dragonets seem to occur most commonly in areas where there is a net erosion of seabed material but in areas where there is significant settlement of finer sediment. For example, they seem common at the fossil beaches around Beaumaris. You can imagine, at these places, there are a lot of seafloor rocks exposed between tides and storms. Yet these places also tend to have significant clear water, suggesting settlement occurs quite rapidly. Painted Dragonets spawn by dancing with each other in the water column at sunset, releasing eggs and sperm into the water. The fertilised eggs are free-floating so it makes sense why they’d mostly occur in areas with relatively calm water where material settles. Otherwise, the eggs would have been swept out to sea long ago.
Settlement Zones
For reasons I’ll explore further in a later blog, we tend to underestimate the importance of these places. Our marine parks are more likely to be in reef zones, like Ricketts Point. Settlement occurs where there are back-eddies. That’s to say, where currents reverse around a promontory or scalloped shoreline, leading to a slowing of water velocity. These places can be where there were traditionally creek lines running into the sea, which build sand banks either side, creating natural deposition zones. Here, the sediment can be finer but the calmer water mitigates for turbidity. They might not look as pretty as reefs but they tend to be more species diverse but consequently, also more fragile habitats.
Evolution and distribution
Our Painted Dragonets are in a genus all of their own, which immediately makes them a little bit special. On an evolutionary scale, the dragonet family of fish (Callionymidae) are quite young and probably evolved between about 14 – 2 million years ago. This was long after the Australian continent drifted apart from southeast Asia, so presumably our Painted Dragonets evolved from a sister species further north. Today, they are found mostly along the southern coast of Australia.
Here are some photos of some of the cousins of dragonets from southeast Asia and the Pacific.
Crepuscular Painted Dragonets displaying
Dragonets are crepulscular, which means active at dawn and / or dusk. This is a common behaviour among their family of fish. It’s at this time that we headed out to fossil beach, Beamauris, in the hope of finding them displaying.
The larger males are mostly absent during the day. Shortly before sundown, however, they come out and display with intent. I watched one male for almost an hour. He did a circuit of his territory searching for females. As he went, he would gulp mouthfuls of sediment and chew on it, expelling the waste out through his gills. Now and again, his activity would sharpen and he would hover up on to a rock. Then he’d start racing across the substrate in quick movements. Sure enough, ahead of him, a small female would be present.
Once a female is found, he would instantly transform into an altogether different fish. He’d erect his dorsal finery, spread his tail and sway side to side. The fins are covered in boldly striped purples, blues and yellows. The eye, face and tail is dotted with similar colours. We also found two larger fish together and they were both displaying, offering the chance to take this photo. I’m sure you’ll agree, this is a fish that warrants a little more regard. Painted Dragonets in Port Phillip Bay are common, exquisitely patterned and deserve a place among the icons of our precious coastline.
