Wild Ocean Blue

As I mentioned in my last post, 2010 is the International Year of Biodiversity. And what better way to start things off than with a neat study from Florida telling us why some fish species are especially important.

This is the story of the red grouper.

Red grouper. by NOAA.

As their name suggest, these chaps are usually red. They can grow to over a metre from head to tail although 50cm (or nearly 2 feet) is more common. They can apparently live for up to 25 years, which is quite a lot for a fish. And like many other fish, red groupers are sex shifters: they are all born as females and after between 7 and 14 years they reajust their sexual organs, transforming into fully-functioning males.

The warm waters of the Caribbean Sea and central west Atlantic, between North Carolina and Brazil, are where the red groupers call home. And it now turns out these fish help to build and maintain their complex reefy  habitats.

“Red groupers are the Frank Lloyd Wrights of the sea floor” said the study co-author Susan Williams, from University California-Davis.

Red grouper. Photo by tiswango.

Felicia C. Coleman from Florida State University’s Coastal and Marine Laboratory led the study in the West Florida Shelf, sending both scuba divers and mini-subs down to spy on the red groupers. The researchers watched on as the fish got busy, digging great holes in the seabed to live in – up to a few metres wide and deep. The fastidious fish then keep their homes neat and tidy, ejecting mouthfuls of sand and sweeping the rocks clean with their tail.

In a series of experiments, the research team temporarily kept groupers away from their excavated abodes (by putting a cage around them), showing just how well they maintain their burrows.

And it turns out that this meticulous housekeeping creates important three-dimensional habitat that many other species rely on, giving a boost to biodiversity wherever red groupers are present; it clears areas of hard rock for corals and sponges to settle on and provides hiding places for spiny lobsters and dozens of other fish species including many that we like to eat such as snappers.

No-one has yet experimented with taking away red groupers permanently to test out this theory; somehow that doesn’t seem like a very good idea, these days.  But this study from Felicia Coleman and colleagues gives us a strong hint that all would not be well if red groupers were to disappear. In their own habitat-building way, they could well be what ecologists call “key-stone species”.

So, without the red groupers it seems likely that a whole host of other species would suffer.

And in the end that’s why red groupers really matter.

In detail:

• Red groupers – Epinephelus morio – are listed as Near Threatened on the IUCN Red List, which is a fairly low threat category but means they are certainly not safe. Many populations are considered to be overfished, especially parts of the Gulf of Mexico, and despite a few recoveries declines have been particularly bad in some areas.
• They are ambush predators, sneaking up on their prey and swallowing it whole, including shrimp, octopus, squid, fish and crabs.
• Other key-stone species include sea otters and starfish. They exert a disproportionate influence (for their size and abundance) on the rest of the ecosystem mainly because of their voracious appetites.

A pair of sea otters holding hands. Just too cute. Photo by joemess

• The red grouper paper can be downloaded for free from the Open Fish Science Journal.

Christmas is here and I couldn’t resist writing about one of the most festive ocean inhabitants, the Christmas Tree Worms.

Xmas tree worm. Photo by Alain76

It’s their outrageous headgear that gives the Christmas Tree worms their name. Most of the worm we don’t see. They hide their rather normal-looking segmented bodies inside boulders of coral. But each worm has a pair of frilly bits called radioles, which they poke out of their burrows to sift food and oxygen from the water.

These scuba-divers’ favourites can put on eye-popping multicoloured displays on coral reefs, like forests of miniature Christmas trees.

Xmas tree worms covering a coral boulder. Photo by will48324

Creep up slowly on one and it will stay out and let you peer closely at its extraordinary spiraled protuberances that can be yellow, orange, brown, blue, red, or white or almost any colour at all. Waft a current of water past them and they flicker out of sight. (I admit that I like to watch for a while, then play magician, waving my hand above them and watching them disappear).

Xmas tree worm. Photo by Tim Sheerman-Chase

So, how do these festive critters take up home in coral in the first place? Well, they may look like nothing but feather dusters, but these hermaphrodite worms come fully equipped with reproductive organs and from time to time will shed sperm and eggs into the sea in the hope they will collide with each other, mixing the gene pool up a little. The resulting larvae then drift through the water for a while before finding a patch of coral they like the look of, settling down and building a chalky tube to live in. The coral polyps then grow around the worm until it is embedded inside the coral skeleton.

And of course these critters don’t come out only at Christmas, but you can see them decorating reefs all year round.

Xmas tree worms. Photo by Nick Hobgood.

As well as looking irresistibly pretty, Christmas tree worms might help to protect corals from attack by canivorous crown-of-thorn starfish, shoeing away any hungry predators that get near, tickling and irritating their sensitive undersides.

Anyway, I think that’s enough facts for Christmas (although do scroll down to the end for some more if you want them), so I wish you all a very HAPPY CHRISTMAS 2009 and leave you with some more photos of these wonderful beasts. Enjoy!

Xmas tree worm. Photo by sarsifa.

Xmas tree worm. Photo by jtu.

Xmas tree worm. Photo by Nick Hobgood.

In detail:

• The Latin name for Christmas Tree worms is Spirobranchus giganteus meaning ‘enormous spiralled gills’. How apt.
• Christmas Tree worms are serpulids, a type of polychaete worm.
• Their radioles grow to about an inch tall.
• There are considered to be two subspecies of S. giganteus, one living in the Indo Pacific the other in the Atlantic and Caribbean. Both subspecies come in a range of colourmorphs.
• Study of the protective role of Christmas tree worms. De Vantier et al, 1986.
• Study of the different colours of Christmas tree worms. Song, 2006. The most popular colour is white.
• Christmas tree worms can live for over 40 years.

Now that I’m back from snowy adventures in the Swiss Alps (under the guise of giving a graduate seminar on science communication – not bad at all) I must tell you about the latest episode of the BBC’s Life series. Because this week they went underwater again, and it was brilliant.

Centre of attention were the invertebrates, a crazy diverse group of ocean critters that get up to all sorts of tricks and never fail to amaze.

Among them were big-brained Australian Giant Cuttlefish.

Giant australian cuttlefish. Photo by Jacob Bridgeman

We watch on as the huge males (up to half a metre long plus tentacles) attempt to woo the opposite sex by putting on a flashy colour display and getting in raucous fights with each other over who’s boss.

Less well-endowed cuttlefish males adopt a very different strategy for passing on their genes to the next generation: cross-dressing. Not very macho, admitedly, but it does the job nicely. By mimicking female colouration, the little males can wander into the mating arena without being chased off. The dominant male thinks he’s lucked out with another female showing up, while in fact the intruding male gets a chance to nip in and mate with the real female. Clever, eh?

Sticking with the cephalopods, we also revisit the Giant Pacific Octopus we met in the first taster episode.

Giant Pacific Octopus. Photo by Schristia

The female lays thousands of eggs inside a cave, tending them like a conscientious farmer tends his crops. It’s such a gargantuan effort for the female that as soon as her young have hatched, she dies. But now we discover that the story of the octopus doesn’t end there.

We get a glimpse of the gruesome reality of what goes on beneath the waves when a giant Sunflower Star (a huge variety of starfish) arrives on the scene – sped up by time-lapse photography – crawls into the cave and drags out the dead mother octopus using thousands of sucky tube feet. Sunflower Star plus a gang of other scavengers swarm over the dead body getting a good feed. It’s not pretty, but it is important, otherwise the oceans would soon fill up with dead octopodes lying about the place.

Sunflower Star. Photo by Ed Bierman

Scavenging echinoderms also make an appearance in an extraordinary Antarctic scene (you can watch this clip outside the UK). The time-lapse photography is simply stunning, as we watch the sea floor crawling with colourful starfish (and rather terrifying three-metre carnivorous worms). All very pleasant until we find out what brought them there: a dead baby seal. But like I said, the world needs its carrion-eaters, scavengers and recyclers to clear things up for us.

In this underwater episode of Life we also see jellyfish eating jellyfish, peep at some on the invertebrate wonders of the coral reefs (including boxer crabs – so cool!), and watch on as herds of spiny Spider Crabs gather together by the thousand to moult and, pairing up, they tumble across the floor in a tight mating clinch.

And I’m now convinced that I don’t ever want to find myself amid a gang of Humbolt squid. If ever there was a creature in the ocean to be a bit wary of, then these are most definitely them.

A razor-sharp, flesh-ripping beak and 70,000 hooks on each one: that’s quite enough to put me off. And it seems they are very clever beings, communicating with flashes of red across their bodies.

Humbolt Squid. Photo by MBARI 2006

But I would like to go diving beneath the Antarctic sea ice. Hang on for the making-of segment at the end of the episode to find out how the film crew took the astonishing footage of the starfish scavengers. An enormous drill makes a tunnel through eight-feet of ice, opening up an eerie blue doorway for the divers to plunge through to another world, somewhere I would certainly like to visit.

And so, once again, the BBC have gathered together some eye-popping footage that serves to remind us just how wonderful, diverse and surprising the oceans can be.

Thank you BBC.

This week an extract of my book Poseidon’s Steed was published in the Guardian, and the book is now available to buy in Europe from various online booksellers. So I thought it was time I blogged about my favourite fish.

One of the questions I get asked a lot is ‘Are seahorses endangered?’. And my answer is, sadly, yes they are.

Seahorses around the world are not only taken from the oceans (both deliberately and accidentally) in scarily high numbers, but they also suffer from the breakdown of their fragile habitats – especially coral reefs, seagrasses and mangroves.

So, what can we do about it? Well, here are my top ten tips for doing your bit to save the seahorses:

1. Don’t buy dead seahorses

This may sound a little odd. Why would you want a dead seahorse?

Because they live inside a coat of bony plates – which take the place of a more conventional suit of fishy scales – seahorses maintain much of their delicate and intricate shape after they die.

Obviously, it’s not quite the same, but much of the seahorses’ beauty lives on after death and there is something to be said for having your very own magical seahorse sitting on your desk (I must admit I have one on my desk, in a little cardboard jewelry box, given to me by a friend who’d had it for years – it must be a long time dead).

Dead seahorse by luv life

But don’t forget it is just the dead body of a fish that once led a quiet, gentle life on the sea floor.

Picking up a dead seahorse from the beach isn’t so bad. But the ones on sale in seaside souvenir shops will almost certainly have been taken live from the sea. So please, don’t buy them. The seahorses will thank you.

2. Make sure your pets were born on a farm

Following the publication of an extract of my book in the Guardian, a few readers have commented that keeping endangered seahorses might not be such a good idea. Have a read of chapter 5 of the book and you’ll find details of modern seahorse farms where seahorses are being bred for the aquarium trade.

Baby seahorses. Photo by pixiesticks23♥ (real busy)

So these days there is no excuse. Anyone who wants to keep these cute animals at home can do so without taking them from a wild.

In the book I also go through some of the pros and cons of keeping seahorses: for you, for seahorses, and for the environment. It’s not up to me to say if people should or shouldn’t keep seahorses – although I can see how lovely it would be to have live, beautiful seahorses in my life every day.

But if you want to keep them, make sure you go to reputable suppliers. Or check out online forums: home aquarists are often giving away spare baby seahorses that were born in their tanks. And this doesn’t just apply to seahorses; always choose captive bred not wild critters for your tank.

3. Don’t buy seahorse medicines

Again, this might sound odd.

Especially to anyone who isn’t familiar with the popular practice in various countries of using seahorses as an ingredient in traditional medicines.

Traditional Chinese medicine texts dating back 500 years prescribed seahorses for all sorts of medical conditions from broken bones and bed wetting, to skin rashes and even a flagging libido. Global demand for seahorse medicines is a driving force behind a growing market in seahorses taken from the sea – at least 25 million of them every year.

Dead seahorses on sale in a medicine shop in Vietnam. Photo by Helen Scales.

Especially worrying is the growing popularity of pre-packaged, off-the-shelf seahorse medicines that use weeny, dark-coloured seahorses that traditional Chinese medicine doctors normally don’t bother with. This means that now any seahorse, no matter what size or colour, can now be used in traditional medicines.

So, if you do use traditional medicines and can afford to buy seahorses (they aren’t cheap), then think about engaging your compassion for the natural world and choose an alternative that doesn’t include endangered species. Because there are lots of alternatives.

4. Protect the seahorses’ world

All sorts of human activities threaten the shallow coastal habitats that seahorses call home including coral reefs, seagrass meadows, mangroves, and estuaries. The list of problems is long and growing and includes pollution, habitat destruction, climate change, and ocean acidification.

And these are all things to worry about and take action over. Especially important is the creation of many more marine reserves or marine protected areas or marine parks or whatever you want to call them. Essentially these are places where the destructive influence of humankind is minimised, by banning fishing, extraction, direct input of pollutants and so on. Some strict marine reserves ban people altogether.

Healthy coral reef. Photo by Jiangang Luo Marine Photobank

There are obvioulsy problems that do not respect the boundaries of marine parks. But we know that protected habitats on the whole are healthier and can cope better when more insidious problems like climate change come along.

Currently less than 1% of the oceans are offered protection from human activities. That number needs to go up – a lot.

You may not have the power to set up your own marine reserve (who does?) but public support of local, regional, national and international campaigns to protect the oceans is vital for action.

5. Stamp out destructive fishing

A major threat to seahorses comes from trawl boats that plough through their habitat. Shrimp trawl boats don’t only catch shrimp but they also scrape up millions of seahorses every year (most seahorses made into traditional medicines are picked out of trawl nets), devastating their fragile habitats in the process. This insensitive, unselective form of fishing has to stop.

Trawl bycatch. Photo from Marine Conservation Cambodia/Marine Photobank

Do your bit by not buying fish that were caught in trawlers. How do you know, you cry? Well, you can ask. More and more these days, supermarkets and restaurants are giving customers information about how their fish is caught. If they don’t say and won’t tell you, then don’t buy.

Check out Monterey Bay Aquarium’s new Super Green List of fish that are good for you and not so bad for the oceans.

6. Take a stand against climate change

We may be releasing carbon dioxide into the atmosphere above our heads, but an awful lot of it ends up dissolved in the oceans where it’s already starting to wreak a particular brand of marine catastrophe. The oceans are becoming more acidic. And the seahorses – along with so many other marine creatures – are going to get hit hard, mainly because lots of them live in habitats that may soon be gone: coral reefs.

So don’t ignore the goings on in Copenhagan next month, because this really matters. Especially if you like the idea of a world with seahorses and coral reefs and other beautiful extraordinary wildlife.

And we can all do our bit to help. Switch off lights, turn down thermostats, insulate your house, recycle, drive less, fly less, ride your bike more. Get involved in campaigns like 350.org. And think of the seahorses while you do it.

7. Go see the seahorses

Aquariums around the world are home to thousands of seahorses and more of them than ever are bred in captivity and not taken from the wild (many aquariums swap baby seahorses when they have too many, which is often the case for the seahorses species that breed happily in tanks).

Seahorse and shrimp fish in an aquarium. Photo by Cal_gecko

Stop for a few minutes and watch the seahorses doing their seahorse thing, and let your thoughts wander off. When they come back, you’ll have your own personal seahorse moment to carry with you and remind you about these amazing creatures and the wild world they live in.

And have a read of the information boards at the aquarium. You never know what you might learn about the world of seahorses.

There’s a great new Secret Lives of Seahorses exhibit at the Monterey Bay Aquarium. But fear not, if you aren’t in California there are seahorse exhibitions all over the place.

8. Go dive for seahorses

If you are an addict of the underwater world like me, then there are heaps of places to go see a seahorse. Well, you can try anyway: they are extremely tricky to spot, with their cunning camouflage and shy nature.

Plus they are naturally rare creatures. You’ll not spot a big herd of them galloping by, but maybe – if you’re lucky – you might catch sight of a solitary seahorse grasping onto a blade of seagrass or coral branch. (Although, a friend of mine has just been diving in Indonesia and swears she saw a sea fan covered in dozens of pygmy seahorses. I’m not sure if she wasn’t just suffering from a case of nitrogen narcosis).

And you don’t have to venture to the tropics to see seahorses. Contrary to popular belief, seahorses inhabit shallow seas along virtually every coastline, tropical and temperate (but they don’t like really cold, icy waters, so don’t bother looking there).

Me and a seahorse. Photo by Steve Trewhella 2009.

A few weeks ago, I saw my first British seahorse off the beach at Studland in Dorset. Yes, that’s right. A British seahorse. There are two species on our fare but chilly shores.

Divers can play an important role in proving that a seahorse is worth more in the water than out. So, go out and support dive operations that care about their local seahorses.

And if you do spy a seahorse, try not to hassle it, poke it, prod it, or blind it with camera flash.

In this picture I am holding onto Troy (or rather, he is holding on to me), but I must point out, I was diving with a licensed seahorse handler (the UK species are now protected). We were conducting a survey, taking down this guy’s vital statistics, and stopped just quickly for an unmissable photo opportunity!

Check out chapter 6 of Poseidons’ Steed for more seahorse spotting tips.

9. Send in your seahorse sightings

Do your bit for seahorse research by getting involved with local seahorse spotting projects. The British Seahorse Survey collects reports of seahorse sightings from across the British Isles – and that goes for live seahorses in the water and dead seahorses too.

Get your seahorse spotting reports in!

10. Spread the seahorse love

And finally… (as they say on the news)

Recycled cashmere seahorse by snaulkter

Raspberry seahorse by snaulkter

I recently discovered these gorgeous cuddly seahorses made from recycled materials by a brilliant artist/designer snaulkter.

They are simply the most adorable – and accurate – depictions of seahorse in fabric that I’ve seen (and trust me, over my years of being a seahorse fanatic friends have given me virtually every beanie baby and cuddly seahorse ever made!). And I love that they are made from reused fabrics. Perfect!

So go get the kids hooked on seahorses, or indulge a grown up’s passion. Each seahorse is a unique critter, and each one is beautiful. Go see for yourself…

So… there you have my top 10 suggestions of how to help save seahorses. I’d love to hear you thoughts of any other things we can do.

Tonight it was the turn of fish to take centre stage on the BBC’s Life. And what an episode it was… absolutely, by far the best yet.

Clown fish. When the head female of an anemone dies, the biggest male has a sex-change & becomes the new dominant female. Photo by ecatoncheires.

Honestly. Trust me. You have to see this one. The early episodes had moments of eyebrow-raising novelty and breathtaking beauty, but so far none of them have truly enthralled me from start to finish. Until now.

And yes, it was about fish, so I’m a bit biased. But really, if anything, I was more likely to say “seen it” to whatever the BBC marched out on my screen.

What we see is scene after scene of surprises, extraordinary behaviour, and frankly stunning spectacles. We have freshwater barbel fish picking the muck off herds of grateful hippos. I never knew this sort of thing went on. Cleaning wrasse and shrimp oncoral reefs, sure. But hippos? Really! The hippos even open up those lethal jaws of theirs and have themselves a fastidious tooth clean.

Then there are the gobies that use their lips to climb up vast, roaring Hawaiian waterfalls. A few of the bravest individuals make it to glorious mountainous pools – fishy heaven. Only, their babies get swept back down the waterfall and out to sea, and the whole, exhausting process starts over again.

There are gorgeous slow motion shots of flying fish. Seeing these guys in real life is such a treat and wierder than you can ever imagine. But why not? Some birds swim don’t they? So why shouldn’t fish take to the air?

But crazier still is when the flying fish start getting together to make more flying fish. On camera, they cast their prodigious eggs and sperm onto a floating palm frond (which I suspect the film crew put there): so much that some of the fish start getting stuck in it and die. Yuck!

Flying fish eggs as sushi. Apparently some people like to eat this stuff. Photo by Roger Jones.

Imagine if you will, that when these fish start getting it on, they can produce enough gametes to sink a boat! The “behind the lens” section at the end of the programme showed a worried captain heaving a massive lump of sticky orange fish goo off the deck after the fish started spawning on his boat. The film crew make a hasty exit. (Also catch the hilarious scenes where the flying fish fly right into the camera team on their little boat).

This episode was especially poingnant for me, because I might have been involved in filming it. I’m not disgruntled that I didn’t get a chance to hob-knob with BBC film crews (although that would I’m sure have been a blast). But I’m miserable because the fish I wanted to take the BBC to film have apparently all gone.

For my PhD I studied I huge species of coral reef fish called the Napoleon wrasse or humphead wrasse (Cheilinus undulatus).

A fully grown male Napoleon wrasse. Photo by bananeman.

These are probably the biggest bony fish that live on tropical reefs and can grow up to nearly 2m long – it would tricky fitting one in a bath tub.

In this episode of Life we see snappers spawning in huge aggregations (these particular aggregations in the Caribbean attract whale sharks who come to feed on the resulting egg soup). Napoleon wrasse do this too. Or at least they used to at a site in the Spratly Islands in the South China Sea where I studied their spawning aggregations.

Every day when the aggregation formed, I went a long to film these giant fish. Then later on, back in Cambridge, I studied the footage and identified individual fish returning to the site day after day, recognising them from the unique patterns of scribbles and lines each one has on its face. Napoleon wrasse, as I discovered, come stamped with an individual faceprint.

Napoleon wrasse scribbles, like a human fingerprint. Photo by Peter Nangle.

Then, after I’d finished my PhD, a few years ago now (that’s how long it takes to film these series) I was contacted by a member of the Life team who suggested we go to the remote island where I did my PhD to film the spawning wrasse once again – this time with proper cameras, and not the sony handicam I used for my research.

It was all looking good until an email came through saying he’d heard that the wrasse were all gone: rumour had it that they’d been taken away to be sold in expensive Asian restaurants, another subject I studied for my PhD.

After following the intimate love lives of individual, gorgeous fish, my Napoleon wrasse have all gone.

Napoleon wrasse eye. Photo by tetzi.

So, all in all, I love this episode of Life. It reminds me why I do what I do. The oceans are beautiful and staggering and still, after all these years that I’ve got to know them, they can take my breath away.

But they also can make me very, very sad.

At least there were some beautiful dancing dragons to help cheer me up.

Oh, and how could I forget. They showed footage of a fish called the sarcastic fringehead. For real.

Today the BBC screened the first episode of their latest landmark wildlife series. This time around they’ve called it, quite simply, Life.

I must admit that back in 2006 when trailers for Planet Earth came out I was a little skeptical that we were really about to witness ‘planet earth as we’ve never seen it before’ as was promised. Surely we’ve seen it all by now?

But no. I was swept away from the opening scene to the closing credits. Planet Earth is undeniably stunning and when I watch it again and again on DVD there are still bits of my mind that get blown away.

And now we have Life. Once again, a little part of me is whispering ‘we’ve seen it all before, we’ve seen it all before’.

And once again, I have to admit that we obviously haven’t seen it all before.

Take, for example, the giant pacific octopus.

Perhaps I should already have known this, but the pregnant female finds herself a safe crevice deep down somewhere out of sight, lays a hundred thousand eggs and slowly starves as she tends and cares for them. By the time the tiny, spotty babies hatch, mother octopus has passed away. Yes it does sound a little sad, but that’s semelparity for you.

Giant Pacific Octopus (Enteroctopus dolfeini)

The first episode offers up other oceanic treats like bottlenose dolphins stirring mud rings off the Florida coast and extraordinary slo mo shots of flying fish as they try to escape sailfish (with footage that for the first time convinces me where the sailfish get their name from). These guys alone are definitely worth tuning in for (it’s on again tomorrow and on Saturday) or watching again on BBC iplayer.

This episode did feel a little bit like a quick fire round.  We see a carnival of snippets without going into too much detail. For example we whiz through madagascar and catch a tantalizing glimpse of a leaftail gecko’s foot with no mention of who it belongs to.

Mossy leaftail gecko from Madagascar. Helen Scales.

But perhaps this was a starter show parading things we’ll see later in the series. We’ll see next week.

And there were a couple of things that I’m sure we have seen before, like the poison arrow frog carrying its tadpoles one-by-one up a tree and plopping each one in a different water-filled bromeliad. These guys hopped through another BBC show a while back I think. But nevertheless they are still quite extraordinary.

We get some gnarly scenes of a leopard seal eating young chin strap penguins, flinging them about like rag dolls. But we are left with the oh-so-cute images of a baby orang utan with its mum while David Attenborough reminds us what life is all about.

So, in my humble oppinion, Life was good. I wonder if next week will be even better. I look forward to finding out.

My offering to help celebrate this year’s International Cephalopod Awareness Days, is the Vampire squid from hell.

Yes, that’s right, you heard: the vampire squid from hell. Vampyroteuthis infernalis to be precise.

And why did I chose this fellow? To shine a beam of light on one of the many fabulous creatures that live hidden away out of sight (except to the most courageous aquanaut) in the inky depths of the ocean.

The Vampire Squid from Hell. Otherwise known as Vampyroteuthis infernalis.

If you don’t believe me, then you can peer briefly into hell yourself by watching a film clip on the BBC’s new online Wildlife Finder.

The vampire squid from hell, ‘the wierdest in this world of the strange’ as Sir David Attenborough puts it, will invade your screen after a few seconds with the dumbo octopus – also pretty wierd (and I love the eerie noises the filmmakers dub on top of these otherwise silent deep-sea scenes).

But I think it’s a little unfair to give these extraordinary creatures such a scary name.

The size and texture of a deflated soccer ball (about a foot long), they make themselves look mean with an array of snaggling spikes. By drawing up the skin between their arms like an inside-out umbrella they give themselves the appearance of an angry red pineapple.

But in actual fact, these spines are quite harmless protrusions called cirri – all part of the vampire squids’ trick of dressing up to look scarier than they really are.

And as Sir David tells us ‘the vampire squid has lights of its own’. These deep sea cephalopods keep bioluminescent bacteria inside their tissues. When the squid gets spooked (for example by a human being blundering past in a deep-sea submsersible vehicle) it waggles about shiny spots of light to confuse any would-be predators, and even lights up a pair of fake eyes to direct attention away from the real, delicate organs.

Vampire squid from hell have huge eyes, possibly the largest in the animal kingdom relative to body size. Six-inch youngsters have eyes the size of a large cherry (about an inch across – give me the same proportions and my eyes would be the size of basket balls). All the better for seeing with in the sunless depths: the only light vampire squid will see is produced by themselves and other living organisms.

And instead of ink they squirt out a jet of bioluminescent particles, another way of messing with the minds of unwanted intruders.

What’s more, these cephalapods aren’t strictly speaking squid. Instead they hover uneasily somewhere between squid and octopodes.

So there you go. Happy International Cephalopod Awareness Day every one.

In detail:

• Vampyroteuthis infernalis was first discovered in 1903 by Carl Chun. He thought it was an octopus because he only counted 8 arms. The 2 extra arms are thin and usually kept tucked away out of sight.
• It’s a bit of a relic, being the only surviving member of the order Vampyromorphida.