Critters in the cold


Squid during nightdive in Camp Cove (Photo: Greg Lecoeur)

I have been back in Perth for well over a month now and it had been close to two months without diving, so I was starting to get anxious to get back in the water. I don’t really have the time to go abroad at the moment, so I jumped on the opportunity to do a short trip to Sydney. A good friend (Greg Lecoeur) had an extended stopover before flying to Europe and asked me if I wanted to join him to find and photograph the elusive Weedy Seadragon (Phyllopteryx taeniolatus). Not only would it mean interesting dives, it also gave me the opportunity to catch up with another friend (the amazing Emma Camp) who does some great research at the University of Technology Sydney. The departure of the trip was a bit rushed but I managed to bring everything, except for my actual camera. Luckily both Emma and Greg are great underwater photographers, so I could enjoy the dives and get better pictures than I could ever take of them, win-win!

The waters around Sydney might be a lot colder than what I am used to, but they do offer some sweet diving and a lot of really interesting critters. The best known and most sought after critters in temperate waters in Australia are without a doubt the Seadragons. Seadragons are endemic to Australia (=found nowhere else) and only live in its southern, colder waters. Two species exist within reach of divers: The Weedy Seadragon (Phyllopteryx taeniolatus) and the Leafy Seadragon (Phycodurus eques). We went looking for the Weedy Seadragon, as the leafy variety is only found further south. I had been told where to look and that there were a lot more interesting critters to find, but when looking for critters it’s always a good idea to have a local guide. Through a friend I got in touch with a very keen local diver who knows the waters around Sydney better than anyone. Andrew (check his site here) kindly offered to take us diving and promised us dragons and much more.


Checking out a gorgeous Weedy Seadragon (Photo: Greg Lecoeur)

Our first dives were in the southern part of Botany Bay, Kurnell is known as one of the most reliable spots for seadragons. After the shock of hopping in 16 degrees cold water (I’m used to nearly double!) I managed to have a look around and appreciate the site. Descent visibility, kelp, rocks, sand and critters, what more do you need? After a mere 15 minutes Andrew delivered on his promise and showed us a beautiful seadragon. We would find a total of 7 that day! They really are amazing and stunningly beautiful animals. While they are related to seahorses and pipefishes, they are still very different. They are quite a bit larger and seem to be the result of a crazy drunk night between pipefishes, seahorses and some strands of kelp. Our presence did not seem to bother them at all, most of the ones we saw were happily pretending to be kelp and didn’t even stop feeding when we came in close for a good look.

Pygmy pipehorse

Find the critter, a Sydney Pygmy Pipehorse (Photo: Greg Lecoeur)

We found some other members of the seahorse/pipefish family that day. Besides a Potbelly Seahorse (Hippocampus abdominalis), Andrew also showed us some Sydney Pygmy Pipehorses (Idiotropiscis lumnitzeri). I was under the impression Pipehorses were a tropics only kind of family, but was happy to be proven wrong. This particular species is only found in the greater Sydney area, but is closely related to the ones I was observing in Dauin and Lembeh. They are at least as beautiful as their tropical cousins and in my opinion a lot braver for spending their days in the cold water. That cold water made Emma and me cut the second dive a bit short, diving in Sydney is all fun and games until someone gets hypothermia.

Pyjama Squid

The beautiful Pyjama Squid (Photo: Greg Lecoeur)

Our second dive day started at Bare Island. I only went for a short dive, but saw 3 juvenile frogfish! What’s more, they were Painted Frogfish (Antennarius pictus), which I also (wrongfully) assumed to be found in the tropics only. It’s funny how after nearly two years of studying critters there is still a LOT I can learn about them. That evening Greg and me went for a night dive at Camp Cove to find a little guy I had been dying to see for years, the Pyjama Squid (Sepioloidea lineolata). The site is a pure muckdive: a calm bay, no structures to speak of, just sand with a smattering of seagrass and some bits and pieces of debris. Needless to say I had a great time in that kind of environment, as would any other diver who likes critters. We found nearly a dozen Pyjama Squid, the first one about 20 seconds after we put our heads down! They are the cutest little things and pretty much nothing is known about them, I might have to consider them for my next project 🙂  We also found a lot of other critters: Bobtail Squid, a juvenile Hairy Frogfish, Toadfish, Bottletail Squid,… Basically everything a muckdiver could want.

Conclusion: Sydney is a sweet place to dive, both for muck and other kinds of diving. But beware of the very real risk of hypothermia (as Emma can attest to), especially if you are doing long dives and not moving much. So bring your warmest wetsuit, tea/coffee for surface intervals and most importantly, don’t forget your camera!


Divers and Seahorses: ADEX

Last week I had the pleasure of attending the annual ADEX Dive Expo in Singapore. If you want to find out what scuba diving is about, or want to realise what a big deal it is, this is the place. Just to give an indication of the growing interest in diving: the expo received close to 60 000 visitors in 3 days! Besides the many stands from dive centres, resorts, photography shops, etc. who were trying to convince people to buy dive trips or equipment, there was a lot more to see and do. Throughout the weekend, there were non-stop presentations by marine biologists, NGOs, photographers, writers and even mermaids.

This year’s theme was “Seahorses“, so some of the world’s seahorse experts such as Dave Harasti, Amanda Vincent and Richard Smith were around to talk about these funky critters. There were speakers from the Coral Triangle Initiative, Greenfins, iSeahorse, Blue Ocean Network and many more NGO’s. It wasn’t possible for me to see them all, but I saw enough to learn a whole lot of new interesting things about seahorses and their conservation.

I was quite honoured to have been invited as well to give two talks. I talked about fluorescence in camouflaged species and how valuable muck diving can be to small coastal communities. From the chats I had with people afterwards, it seems I wasn’t talking absolute nonsense and people were actually interested in what I had to say. While it is too early to tell, in the future there might even be some interesting projects coming out of these meetings.


Explaining the value of Muck Diving

The most interesting facts I’ve learned this weekend? It seems seahorses often end up as prey for frogfish, scorpionfish and even the occasional octopus. This is also the reason why successful marine protected areas with lots of predators might lead to less seahorses in those protected areas. I’ve also noticed once again that there is more and more demand for truly sustainable dive tourism in a way that really benefits local communities and not just the owners of dive resorts.

Spending a few days in the comfort of modern Singapore was nice, but now it’s time to get back to work. And for now work = fieldwork!  😀 Yesterday I arrived in Dauin accompanied by none other than Luke, my very good friend and trusty science hobbit! Keep your eyes on the blog for our adventures looking for baby critters…

Little known facts about seahorses

I have been reading up about seahorses recently and discovered some interesting little bits of information I could not help but share. While seahorses seem to be a big favourite for divers and non-divers alike, we actually know surprisingly little about them. Some of their strange quirks are well known. The fact that the males get pregnant is probably one of the favourite and most retold bits of knowledge about them. I want to go a bit further and more interesting than that, so let’s get started.


The fused jaw of a seahorse (Source)

Seahorses belong to the family of Sygnathidae, which  translates as “fused jaws”. What this means is that all seahorses and pipefishes have jaws that are stuck together, they can’t open them anymore. So if you were to imagine eating like a seahorse, try gobbling up your salad, steak, pizza, apple,… with clenched jaws, while only using your lips to help you suck the food in. A good thing seahorses do not have teeth, as that would make it even more difficult!

Best of Dauin_Seahorse Estuary_MDB

Hippocampus taenopterus, getting ready to growl

Another quirky thing seahorses do, is that they make noise. They make two distinct types of sounds: “clicking” and “growling”. I absolutely love the idea of a growling seahorse! It seems they do this when they are stressed out and it might even be some sort of escape mechanism to startle predators. Most likely because those predators would be laughing too hard because a seahorse just growled at them… The clicking sounds are mostly used during courtship and mating, so not only do seahorses growl to chase away predators, they also serenade their partners to get them in the right mood. Strange little critters indeed.

To keep up with the strangeness, have you ever wondered how strange the tail of a seahorse actually is? Probably not, I definitely hadn’t before reading this article.  The tails of most animals are round, but nearly all seahorses have square tails. As it turns out, this square shape is better at grasping and holding items. At the same time it offers a higher resistance to crushing than a round tail would. So perfect for a camouflaged critter which spends most of its time clinging on to objects, pretending to be something it is not to avoid getting eaten by predators.

Seahorse tails

Different 3D printed models of seahorse tails (Source)

Best of Dauin_Seahorse thorny_MDB

Hippocampus histrix

The objects seahorses hold onto can be anything, usually they cling on to objects like seagrass, algae, gorgonian seafans, etc. But they do not seem to be very picky at all. This article showed how seahorses living in areas with a lot of plastic actually use that plastic as camouflage. The seahorses even changed their colour to resemble the colour of the plastic and the spots on it. Unfortunately I cannot put the original pictures online due to copyright issues, so if you want to see them, follow this link. Since seahorses don’t really mind what they hold on to, artificial structures can be used to provide habitat for them when their natural habitat has been destroyed. This way populations can continue to exist until the natural vegetation has recovered.

Loss of habitat is one of the risks that endanger seahorses, the trade for traditional Chinese medicine is another big threat to them. IUCN has listed 7 species as Vulnerable and one species as Endangered, but most species have either not been assessed or we lack the data to assess whether or not they are endangered. To combat the illegal trade and offer some means of protection, all seahorses are listed with CITES, which means trading them is strictly controlled. One of the simple rules used to do this, is a size limit of 10cm. This size ensures that most traded seahorse species are mature individuals who can reproduce and that juveniles are left alone.


Hippocampus pontohi

The fact that we don’t really know how many species of seahorses exist, makes protecting them hard. Estimates of the number of seahorse species range from 40 to 48 species. It is quite likely new species are still waiting to be discovered, though the opposite might happen as well. Two species of pygmy seahorses (Hippocampus severnsi and Hippocampus pontohi) were described in 2008. But recent genetic analyses showed that they are actually the same species which comes in different colour variations.


If you want to know more about seahorses or just have a good laugh, check out this great video from Ze Frank with some more true facts about seahorses.

Winged Pipefish

As the research that I am doing looks at some of the strangest critters you can find in the ocean, it seems only right to give them a space on this blog. The little guy who kicks of the page is a little known pipefish: the “Winged Pipefish”.

Adult Winged Pipefish

Winged Pipefish

While doing surveys on the Critters@Lembeh housereef, I found a large (15cm) Winged pipefish (Halicampus macrorhynchus) chilling out on a patch of rubble. I have seen this species a few times before on dives in Indonesia, and always liked it a lot, even if you don’t hear or read about them very often. Maybe I like them just because it’s less of an in your face – “take a picture of me now, I’m AWESOME” – kind of critter than some of the more popular ones, but they still manage to be pretty cool creatures. As with most other pipefishes, little is known about their life history and behaviour. Besides the original description, I found a grand total of 0 (=zero) scientific papers that focus on the ins and outs of this amazing fish…

Juvenile Winged Pipefish

Juvenile Winged Pipefish

So here is what we do know: The juveniles are beautiful, mimicking algae or bits of seagrass. The tiny juvies have got large appendages resembling wings, hence the name. The wings don’t serve many other purposes besides looks (more on that later). They can be found on sand or rubble, often in areas with a lot of plant debris or seagrass. I think they are cutest juvenile pipefish you can find, but they are a very rare find, in 12 years of diving I only ever managed to find a single one.

With age the wings appear to get smaller (they grow into them). In big adults the only things that can be seen are small skin flaps on the side. The adult pipefish still look quite amazing, and can display all kinds of colours, ranging from brown to yellow to pink. At this stage, they are more commonly found on coral rubble or coral reefs.

The biggest adults can get overgrown with algae and are extremely well camouflaged, like the one on the housereef. The big ones I’ve seen were always on coral rubble and looked kind of gritty and tough (as far as pipefishes can look tough).

Halicampus macrorhynchus

Halicampus macrorhynchus

For those if you interested in finding or photographing one of these guys, Winged Pipefish range from the Red Sea to as far as Hawaii and Panama. Look in rubble, sand or seagrass patches between 3m and 25m.

Spot the pipefish...

Spot the pipefish…

Oh, and the function of the skin flaps and wings? It is assumed that they help to break up the shape of the fish, making it even harder to find for predators or divers.