Critters

Flamboyant Cuttlefish

/ Maarten De Brauwer / 10 Comments

It’s been a long time since I put a critter in the spotlights, so it’s time for one of my personal favourites: the Flamboyant Cuttlefish! I am definitely not the only one to like this amazing little animal, for most divers it is high in the top 10 of critters to see. With good reason as well, Flamboyant Cuttlefish are one of the most beautiful and intriguing inhabitants of sandy dive sites.

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Flamboyant Cuttlefish (Metasepia pfefferi) striking a pose

The small cephalopod many divers call “Flamboyant Cuttlefish” are in fact two species: the Flamboyant Cuttlefish (Metasepia pfefferi) and the Paintpot Cuttlefish (Metasepia tullbergi). The first one lives in Malaysia, Indonesia, Papua New Guinea and the north of Australia. The Paintpot Cuttlefish is found further north, from the Gulf of Thailand all the way up to southern Japan. Both species are classic muck dive critters, they only occur on muddy or sandy bottoms, so you will have to move away from coral reef to encounter them.

flamboyant-cuttlefish3So why does this animal deserve the effort of searching sandy plains for days on end, in the hope catching a glimpse of it? To start with (the name is a bit of a give-away) they are very flamboyant critters. We are talking yellows, pinks, blacks and whites, all at once! If that wasn’t enough, they often change their colours into “traveling waves”, even more so than normal cuttlefish or octopuses. From my experience, smaller Flamboyant Cuttlefishes have the brightest colours and make the most extravagant displays. When I write small, I do mean really small: adults do not grow much bigger than 8cm. They ideally sized Flamboyant Cuttlefish for the best colour-show  would be around 3-5 cm!

If finding an animal that size seems difficult, you might also want to consider the following. When they are not disturbed, hunting, or mating, Flamboyant Cuttlefish are anything but flamboyant. In their “standard” state, they blend in perfectly with their background, so they will be a mottled grey, brown, or black. For this reason some divers or photographers are tempted to disturb the animal to better see its colours. It is obvious that this is a bad idea, as it will stress out the cuttlefish. Be patient  instead, observe it for a while and you might even be rewarded by seeing it hunt small shrimp, lay eggs, or even mate!

Flamboyant cuttlefish showing its colours
The same animal only a few seconds later

Another thing that is special about them is that they do not swim, but walk across the bottom. To do so they use two of their arms and an adaptation of their mantle. They can swim, but only do so when they’re startled and over short distances. I could easily spend an entire dive watching these guys wander across the seafloor, little blobs of colour on a quest to eat as many shrimp as possible. It might be because of the awkward way they walk, but I always imagine them to be mildly grumpy animals. A bit like an old man with stiff joints who can’t walk that well, grumbling to himself about how the terrible weather…

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A juvenile Flamboyant cuttlefish (M. pfefferi) walking across the rubble

An interesting mystery surrounding these animals is whether or not they are toxic. Their colours would suggest some form of aposematic colouration, in the same way nudibranchs advertise their toxicity with bright colours. Some authors have even suggested flamboyant cuttlefish might mimic nudibranchs such as the Ocellate Phyllidia (Phyllidia ocellata). I have however, not read a single bit of conclusive evidence of this. It seems to be one of these “facts” people have assumed, written about and then it just got copied. To date there seem to be no papers out their describing whether or not Flamboyant Cuttlefish really are toxic, and which toxin they would produce. If anyone would have come across that information, I would be very grateful if you could share it with me and the rest of the world.

As is often the case with small critters, we don’t know very much about them. But that doesn’t have to stop us enjoying looking at them. Which is why I couldn’t resist adding a video of one of these guys. The title is a bit too sensational, but the footage is great, enjoy!

 

 

Critters in the cold

/ Maarten De Brauwer / 4 Comments
Squid

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.

Seadragon

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.

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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.

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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!

 

Blue-ringed Octopus: cuteness with a twist

/ Maarten De Brauwer / 2 Comments

I am definitely not the first person to write about the Blue-ringed Octopus, and once you’ve seen one for yourself it is quite understandable that people get excited about them. Blue-ringed Octopus are probably one of the only invertebrates you can call “cute”. With their small size, interesting behaviour and iridescent blue rings they look like something out of a cartoon. Add the intriguing fact that these animals are also one of the world’s most venomous animals, and it becomes logical that people are interested in these critters.

Blue-ringed Octopuses are several species in the genus “Hapalochlaena“, depending on which source you check, there are anything between 3 to 10 species. They are all small octopuses, with the biggest one (Hapalochlaena maculosa) growing to only 15cm (body + arms). They are found from the centre of the Indian Ocean to the west of the Pacific Ocean. While their colours might make you think they belong in similarly colourful tropical reefs, they are actually more frequently found in the temperate waters of southern Australia.

A fact that is repeated very often is just how venomous these little guys are. So I won’t spend too much time on it here, but if you want to read more about it check out this link to learn all about the technical toxic details. The short version is: if you get bitten, you’d better hope to have someone nearby who is highly skilled in CPR. One of the more fascinating effects that occur when bitten is “locked in syndrome“, where you appear to be dead, but are actually still aware of what is going on. If that and near-certain death doesn’t stop people from harassing them to get a nice picture, I don’t know what will 😉 .

The most conspicuous features of the Blue-ringed Octopus, its blue rings, are actually hardly visible for most of the time. When you find one while diving and you don’t bother it too much, they look like any other well camouflaged octopus. The blue rings are a warning signal they only show when spooked or threatened. The mechanism of how they show those rings is a really neat one. The rings are pigmented cells that are usually covered by muscles that are contracted above them. It is only when the octopus relaxes those muscles that the blue rings show. Like a blanket that’s pulled away when unveiling a work of art. For more details, check out this paper.

One of the most interesting things I could dig up about this critter is about the way they mate. It turns out that Blue-ringed Octopuses can’t tell the difference between males and females! Males will try to mate with any other Blue-ringed Octopus they encounter, pouncing (that’s the technical term, trust me) on the potential partner and inserting their hectocotylus into the mantle cavity of the partner. It’s only after they insert this modified mating arm into the other octopus, that they can tell if their partner is in fact female or not. If the partner turns out to be another male, they amicably part ways, no harm done. In case they get lucky and their partner is a female, the male clings on for a long time: usually more than 90 minutes, but sometimes to over 4 hours! As a matter of fact, it seems the male tries to hang on as long as the female allows it, only breaking contact when forcefully removed by the female. If you are interested in the love life of small octopuses, you can read the original study here.

There is a lot more to find out of the Blue-ringed Octopus, such as the very basic question “How many species are out there?”. Considering that this animal is one of the most popular critters in muck dive tourism, it is surprising how little we really know about them. For my research I mostly look at fish, though I am always on the lookout to see what the best places are to find and study other interesting species. So who knows, I might just have a closer look at them in the future.

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Photo: Maarten De Brauwer

Mandarin madness

/ Maarten De Brauwer / 2 Comments

My last trip to Komodo was a successful one, not only because of the data I collected or the nice group on the boat, but also because I managed to have a good look at two very elusive critters, one of them a first! I had seen Mandarinfish (Synchiropus splendidus) before, but this was the first time I had a proper look at a Picturesque Dragonet (Synchiropus picturatus).

Mandarinfish (Synchiropus splendidus)
Picturesque Dragonet (Synchiropus picturatus)

Both species are closely related Dragonets belonging to the genus Synchiropus. They are exquisitely coloured, which makes them big hits both with divers and marine aquaria hobbyists. The colours and patterns of the picturesque dragonet have earned it the synonym of “psychedelic mandarinfish” or even “LSD-fish” in German! Of the two, the mandarinfish is best known to divers, probably because it is found more frequently in areas where divers are likely to dive, unlike its psychedelic sister-species.

Both species are found in the Indo-West Pacific, they range from the south of Japan to the north of Australia. The best places to spot them are Indonesia and the Philippines. They are found in sheltered lagoons, usually in areas with coral rubble. You can also find mandarinfish in stands of branching corals. Picturesque dragonets are more frequently found in areas with silty bottoms close to mangroves. Both species are shallow water fish that are rarely seen deeper than 20m.

The best time to see mandarinfish is at dusk or late in the afternoon on overcast days. At these times the fish come out of hiding to spawn. Both species live in small social groups which usually consist of a male and a few females. The males are easily recognized by their larger size and long dorsal fin.

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Two Picturesque Dragonets (female in the front, male at the back)

As is the case with many secretive critters, we don’t know very much about them. The things we do know show that there is more to them than just a pretty face. For example, they secrete a thick mucous that might even contain toxins. According to the literature, this mucous smells bad and tastes bitter, which makes me wonder exactly how they found this out 😉 Regardless of research methods, this toxicity means that the highly visible colours could in fact be a warning signal to potential predators, much in the way nudibranchs advertise their toxicity. For those interested in impressing their fellow divers, this trick is called “aposemetic colouration“.

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Mandarinfish – a fierce predator?

Mandarinfish are tiny carnivorous fish, which feed on tiny prey. Too bad they are so small, just imagine how much fun it would be to see a great white shark in the colours of a mandarinfish?!? Until the day an evolutionary trip-up creates a giant mandarinfish stalking the oceans, they feed mainly on small crustaceans, small molluscs and fish eggs. Which might be more convenient for the many people that keep these small fish in aquariums.

And make no mistake about it, both species are VERY popular in the marine ornamental trade. Research in Batasan Island (near Bohol) in Philippines showed that in 2000, between 1800 to 2400 mandarinfish were exported per month! If you have ever searched for mandarinfish while diving, those numbers will seem even more impressive. Fishermen usually catch the fish with miniature spearguns, since other methods are not as successful. This method obviously inflicts damage on the fish, often leading to the fish dying either shortly after being caught or during transport to aquariumshops. Another problem with catching mandarinfish for the aquariumtrade is that people prefer larger fish. A trend that causes the larger males to disappear first, which can in turn lead to reduced reproduction rates for the remaining fish.

These lovely critters might be very popular with aquarium enthusiasts, unfortunately they are difficult to keep alive in a tank. The fish require specific food and shelter, lack of those are the cause of many mandarinfish dying shortly after they’ve been bought by their new owners. There have been some reports of mandarin spawning in tanks, but raising the larvae to healthy adults is still difficult. As far as I could find, the vast majority of mandarin fish sold in aquarium shops are still caught in the wild, which might have a big impact on fish populations in the ocean.

Might have a big impact, since we don’t really know. Neither species has been assessed by the IUCN, so we don’t know if populations are in decline and if they are at risk of extinction. So until we do, enjoy looking for them during your dives, but think twice before buying one!

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