Welcome to the final article of Deep Sea Week. To round off this celebration of the weird, wild and wacky denizens of the deep, it’s time for a monstrous miscellany – a look at some of the animals cut from previous articles that were just too downright extraordinary and intriguing to ignore.
The infamous blobfish: the classic image of this slimy, ugly, sad-looking fish has been circling the internet for years now. Its name comes about, quite clearly, because it resembles a shapeless blob, but why does it look like that?
In fact, it usually doesn’t. In the deep sea, where the water pressure is several hundred times that at the surface, gas bladders, which are often found in fish, become inefficient at maintaining buoyancy. The gelatinous mass of the blobfish allows it to simply float above the ocean floor without expanding any energy on swimming, which is just as well because it has very little muscle structure. In its natural habitat, the blobfish looks like a normal fish; only when it is removed from the supporting medium of water does it collapse into that familiar slimy blob.
First of all, yes that really is the name of this animal (if you’re uncomfortable calling it that, you could always use its alternate name: flying buttocks), and secondly, yes it really is a worm. Worms, it has to be said, are not generally known for being spherical in shape, but this one breaks the mould. As you can see, the animal bears a strong resemblance to a disembodied pair of buttocks and even its scientific name, Chaetopterus pugaporcinus, means ‘resembling a pig’s rear’.
The pigbutt worm has a segmented body but its middle segments are highly inflated, giving the animal its characteristic round shape. It eats floating plankton, which it captures using a net of mucus. Very little else is known about these strange and mysterious animals, and it is still being debated as to whether this form is the adult or juvenile stage. It seems too big to be a larval form, but then again no individuals captured have possessed sexual organs, so who knows?
At the bottom of the ocean, fish don’t swim around: they stand. The tripod fish spends almost all of its time standing motionlessly on what appear to be stilts, waiting for edible food particles to come its way. These three ‘stilts’ are actually extensions of their two pelvic fins and the lower half of their tail fin. In some instances, they can be almost a metre in length.
The tripod fish has eyes but they are tiny and, in any case, are practically useless in the endless darkness. Instead, those long fin extensions act as antennae, sensing movement in the water. All the animal needs to do is stand in one place and face upstream; the current will deliver food directly to it without the fish ever needing to use valuable energy. It’s a bit like you or me sitting in a chair and grabbing food as it is continually brought within arm’s reach by a conveyer belt.
Very occasionally, the tripod fish does move and it goes for a short swim. When it does so, those fins that so rigidly held the fish above the sea floor suddenly become flaccid and flexible, trailing behind it.
In a desert of dark, ugly, abhorrent creatures comes the pretty, glowing oasis that is Tomopteris. It’s a type of bristleworm that undulates and ripples through the water using those shimmering leg-leg structures (or parapodia, if you want to get technical). Some species glow blue, but one glows yellow – one of the very few marine creatures with yellow bioluminescence. A few types are even capable of dispelling bioluminescent mucus, which distracts predators, making them go after the discharged glow rather than the animal itself.
Question: what do the three fish in the composite picture below have in common?
Answer: they are all the same species, the flabby whalefish.
These three fish look so different that until 2009 they were thought to belong to three completely different families. In the picture above, the one on the left was called a tapetail; the one on the top right a bignose fish; and the one on the bottom right a whalefish. But there was a problem. Only juvenile tapetails, male bignoses and female whalefish had ever been found. This is not as unusual as it may first appear – in fact, many deep-sea animals are known only from one sex or one stage of their life cycle – but a closer look at these three creatures revealed that they all belonged to the same species.
The three families have since been merged into one to create the flabby whalefish. If a juvenile (a tapetail) transforms into an adult male (bignose), his jaw fuses shut and his stomach disappears. The only sustenance he can now obtain are from the shells of prey he may have consumed whilst in his juvenile form. The rest of his life is devoted to finding a female, using the large nasal organ that gives him his name. In contrast, adult females are large and beastly, and they retain their mouths and stomachs, eating whatever they can fit inside their elastic gullets.
The ocean abyss is such a mysterious and little studied place that even after an entire week of looking at its strange inhabitants, there is still so much more to see and explore. No doubt we’ll be returning to this eternal darkness at some point in the future to see what other monsters are lurking about within its depths…