CARIBBEAN REEF SQUID REVISITED: SUPERPOWERS & SQUID SEX


Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

CARIBBEAN REEF SQUID REVISITED: SUPERPOWERS & SQUID SEX  

The Caribbean reef squid Sepioteuthis sepioidea is a small squid species of (mainly) the Caribbean Sea and the Floridian coast, and the most common in its range. These squid tend to form small shoals in and around reefs. Right now, in June, is a good time to find these creatures swimming in groups – all these photos were taken during the last fortnight. I wrote about squid a while back (3 years, maybe)? This post includes some parts of the earlier one, with all-new images. Squidmages, even.

Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

Squid are voracious eaters, dragging their prey to their mouths with some or all of their 10 limbs and using their beak to cut it up. The target species are small fish, molluscs and crustaceans. The squid have a ‘raspy tongue’ known as a radula which further breaks up the food for easy consumption.

Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

REEF SQUID SUPERPOWERS (SUPERCOOL)

  • Squid are capable of brief flight out of the water (a fairly recent discovery)
  • They can also hide from / confuse predators by ejecting a cloud of black ink
  • Squid can change colour, texture and shape, and can even match their surroundings
  • This enviable power is used defensively as camouflage or to appear larger if threatened
  • It is also used in courtship rituals (something that humans might find most disconcerting)
  • Colour patterns are also used for routine squid-to-squid communication AND GET THIS:
  • A squid can send a message to another on one side, and a different one to a squid on the other side

Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

SQUID SEX (1) “ROMANCING THE SQUID”

  • A male will gently stroke a female with his tentacles
  • The female will (most likely) flash an ‘alarm’ pattern. She’s hard to get.
  • The male soothes her (don’t try this at home, guys) by blowing and jetting water at her
  • If this doesn’t go well, he’ll move off, then repeat the routine until she sees his good points
  • However this on / off courtship can last for hours until at last he succeeds and then…
  • … he attaches a sticky packet of sperm onto the female’s body (romance is not dead on the reef)
  • She then reaches for it and moves it to her seminal receptacle
  • Meanwhile he stays close, emitting a pulsing pattern, as well he might after all that palaver
  • She then finds a safe place to lay her eggs. Job done.

Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

SQUID SEX (2) IT ALL ENDS BADLY. VERY BADLY.

  • As soon the female squid has laid her eggs, she dies at once
  • The male squid lives a bit longer and… may have other packets to stick on other lady squid
  • But then in the end he dies too
  • It’s all horribly reminiscent of Romeo and Juliet. The lovers die. But no the balcony scene

Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

THE CORRECT PLURAL OF SQUID

I had an unwise look online, always a hotbed of conflicting opinions. Inserting an algorithm into the interstices of the internet proves conclusively that the plural of squid is… squid. One squid, ten squid, a group of squid, a plate of squid. Unless, that is, you are talking about more than one of the many squid species, when you could also have ‘I collect both reef and giant squids’. “Squidses” sounds fun but is sadly not permitted.

Caribbean Reef Squid, Bahamas (Melinda Riger / G B Scuba)

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Credits: As ever (for fabulous underwater pics) Melinda Riger of Grand Bahama Scuba; research sources include MarineBio; Animal Diversity Web (Michigan Uni)

GREEN TURTLES & TURTLE AWARENESS ON ABACO


Green Turtle, Bahamas (Adam Rees)

GREEN TURTLES & TURTLE AWARENESS ON ABACO

There’s something slightly unsettling about the perspective of the header image, with foreshortening suggesting that the turtle is actually a gigantic creature with a tiny diver swimming close to it…

I don’t seem to have given green turtles much space in the past, the most frequently photographed (and therefore featured) species being the hawksbill. This post is both to right the wrong, and to provide some information about the species.

Green Turtle, Bahamas (Adam Rees)

Friends of the Environment has produced an interesting short guide to the sea turtles of the Bahamas. One of the many facts included is that 5 of the 7 sea turtle species in the world can be found in Bahamian waters. The turtle protection law is also given – also the way to report turtle nests so they can be watched and protected.

Green Turtle, Bahamas (Adam Rees)

The 4 main species are the hawksbill, green, loggerhead and leatherback. The 5th and lesser known one is the Olive Ridley turtle. The differences between most of these is considerable, as can be seen from this IUCN-produced Identification Chart (credits as shown).

Another useful source of information for green turtles is this extremely well produced poster illustrated by the excellent Dawn Witherington, who has somewhat (and deservedly) cornered the market with this kind of large-scale infographic. The sea turtle series is so helpful that I have dedicated a whole page to them HERE. Dawn also created the LOXAHATCHEE poster series covering such topics as Lionfish, Sea Grasses, Land Crabs, Bonefish, Coral Reefs and more

Green Turtle, Bahamas (Adam Rees)

All photos: Adam Rees Photography, with thanks for use permission here and elsewhere

‘SOCIABLE DOLPHINS’: MELON-HEADED WHALES


Melon-headed whales, Bahamas (BMMRO / Field School)

‘SOCIABLE DOLPHINS’: MELON-HEADED WHALES

Last month, BMMRO undertook a joint expedition with FIELD SCHOOL to carry out research on sperm whales. This took them out into deep water, where another, quite different, cetacean species was also encountered on the final day – a huge pod of more than 100 melon-headed whales Peponocephala electra.

Melon-headed whales, Bahamas (BMMRO / Field School)

The melon-headed whale is in fact – like the FALSE KILLER WHALE I recently wrote about – a species of dolphin. It is sometimes more accurately called the melon-headed dolphin, which removes any confusion. These creatures are oceanic, preferring deeper waters. For that reason they are not often encountered, despite being quite common in tropical and sub-tropical waters around the world.

Cetacea range map Melon-headed Whale.PNG

Melon-headed whales, Bahamas (BMMRO / Field School)

The MHW belongs to a dolphin species commonly known as blackfish. Other dolphins in this group included, for the Bahamas, the pygmy killer whale and the more frequently encountered pilot whale, a species than can be seen in the Sea of Abaco.

In some of these photos you can see the distinctive white lips of the MHW Melon-headed whales, Bahamas (BMMRO / Field School)

Melon-headed whales are notably social animals. They live in large groups – often more than 100-strong (as the expedition found), up to as many as 1000 individuals. Within these large groups, smaller groups of a dozen or so form and stay close as they swim.

Note the ‘Rainbow Blow’ caught in this photoMelon-headed whales, Bahamas (BMMRO / Field School)

MHWs appear to communicate or perhaps to bond by touching flippers. MHWs also associate with other dolphin species, and they have even been recorded with large whales such as humpbacks.

Melon-headed whales, Bahamas (BMMRO / Field School)

Other observed behaviour includes sub-surface resting in numbers, boat-wave riding, and so-called ‘spy hopping’ (above). This last activity may be carried out by several resting animals,  which jump vertically out of the water and splash back again into the ocean (see also the Header image).

Melon-headed whales, Bahamas (BMMRO / Field School)

This video was recorded during the expedition. You’ll get a very good idea of the size of the group from the drone shots as they pull out. I doubt that many people would expect to see such large sea creatures in such numbers – it must be an awesome** sight.

10 MELON-HEADED FACTS WITH WHICH TO ASTOUND YOUR LOVED ONES
  • The MHW’s head is rounded, lacking the obvious beak of more familiar dolphins
  • The darker grey face is sometimes called a ‘mask’
  • Their distinctive white lips are a good identifying feature
  • They are capable of swimming at very fast speeds
  • Like other dolphins, they make series of low jumps out of the water as they swim
  • Their groups often contain 100 individuals, up to as many as 1000
  • An adult grows to around 3m / 10′ long
  • They live for at least 20 years, and females may live as long as 30 years
  • As with many certaceans, their favourite food is squid
  • Oh, did I mention that they are really dolphins and not whales at all?

CREDITS: all fantastic photos & the original of the video clip – © BMMRO /  Field School

** In its true and original meaning of ‘inspiring wonder and awe’ (historically, in a religious sense), rather than the diluted modern usage as in ‘awesome pizza’ or ‘awesome selfie’

SHARKS! APEX PREDATORS IN THE BAHAMAS


Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

SHARKS! APEX PREDATORS IN THE BAHAMAS

Immersion in current affairs these days brings inevitable acquaintance with sharks of various kinds, and all best avoided. Let’s have a look the real thing, the apex marine predators that in the Bahamas are all around you once you leave the safety of the shore. I haven’t featured them for ages, and it’s always a pleasure – a slight thrill, even.

Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

I don’t do scuba, indeed my swimming would easily be outclassed by a competent four-year old. But I see these creatures when I’m out fishing; or as they hang in the breaking waves off the Delphi beach, watching intently for a meal.

Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

We watch them (and stingrays) from the balcony as they lazily make their way round the margins of the wide bay, from little ‘uns to (recently) a huge bull shark. We watch as, when someone is in the water, they change course slightly to pass by them. So far, anyway…

Feeding sharksSharks feeding in the Bahamas (Melinda Riger / Grand Bahama Scuba)

The one that got away… (a sad sight)Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

I once took a rather primitive underwater camera with me while snorkelling in Fowl Cays National Park. This was several years ago, when I believed a cheap 2mb camera might turn me into one of the Blue Planet team. I was wrong. The shark I saw, apparently some 20 miles away (when I examined the image) – well, that’s its tail, top left…

Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

Just to look at these images is to understand that when you are in the sea, you are in the sharks’ environment. They are the masters of it. They have their rules, and they are not much interested in you… unless you break them. Or so the theory goes.

Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

This fine shark below exemplifies the power and the menace of the shark. A creature to be admired, but also to be respected.

Sharks in the Bahamas (Melinda Riger / Grand Bahama Scuba)

All fantastic photos: Melinda Riger / Grand Bahama Scuba

BAHAMAS REEF FISH (43): CUBERA SNAPPER


BAHAMAS REEF FISH (43): CUBERA SNAPPER

The cubera snapper (Lutjanus cyanopterus) is the largest snapper species. Adults may grow to 5′ long but they average around 3′ long and weigh 40 lbs or so (the record apparently stands at a massive 126 lbs). These are game fish, and they are a commercially important species. They are also IUCN listed as vulnerable, perhaps for that very reason. 

10 CUBERA SNAPPER SNAPPY  FACTS

  • The largest of a large number of snapper species in the western Atlantic
  • Feed on fish, shrimps & crabs, with large strong teeth (see pics) and jaws
  • Among their (few) predators are sharks, barracuda, and moray eels
  • Edible, but beware of the danger of CIGUATERA poisoning
  • In summer months, spawning is governed by lunar cycles
  • Cuberas form huge spawning masses (to 10k) in offshore shallows
  • Sadly the resulting eggs and larvae are rich pickings for predators…
  • Youngsters live in sea grass or mangroves for protection
  • Cuberas are game fish with commercial importance
  • IUCN listed as vulnerable – largely courtesy of mankind (see »)

RANGE FINDER

Cubera Snapper Range Map (wiki)

CONSERVATION MATTERS

Overfishing is one of the greatest threats to the species. Those young fish that are not predated naturally and grow to adulthood are targets for fishermen. There’s no prissy ‘catch & release’, as with bonefish. At spawning time, as the fish instinctively (and predictably) mass as the moon dictates, so do the human predators. The spawning sites are where the best protection can be given, to ensure the annual reproductive cycle is uninterrupted. If not, ‘vulnerable’ will soon give way to ‘endangered’…

I’d been going to pull apart a long recipe for the “wonderfully sweet white meat ” of this fish for the tastiest morsels of info, then (not being a cook) I quickly tired of the idea. Sorry to disappoint. 

Credits: Melinda Riger for the wonderful photos; range map from wiki; magpie research pickings, including (but not limited to ) Nat Geo

SOUTHERN STINGRAYS: BAHAMAS REEF FISH (41)


Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

SOUTHERN STINGRAYS: BAHAMAS REEF FISH (41)

Anyone who has scuba-dived or snorkelled around the bright coral reefs of the Bahamas, or hunted bonefish out on the Abaco Marls will have come across Southern Stingrays Dasyatis americana. And there are certain places (eg Manjack Cay) where you can actually feed them – and not come to any harm

Southern Stingrays, Manjack Cay, Bahamas (Samantha Regan)

FEED THEM? AREN’T THESE GUYS LETHALLY DANGEROUS CREATURES?

Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

The name that always comes to mind in connection with stingrays is poor Steve Irwin, the charismatic Australian wildlife expert who was tragically ‘stung’ over his heart as he swam close over a ray while filming underwater. But this was, it would appear, a dreadful combination of circumstances with a terrible outcome.

Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

The ray’s stinger is in fact an erectile venomous barbed spine near the base of the tail and not on the end of it (as one might expect). But these creatures are not out to harm you – though of course when you are in their environment you should accord them the respect that they merit.

Southern Stingray (Tomas Willams, wiki)

If you are walking / wading in the water, avoid the risk of accidentally treading on a ray. Best to shuffle your feet forward in the sand; if there’s a half-concealed ray feeding or resting on the bottom nearby, it will swim away peacefully. I took the photo below while bonefishing on the Marls; the ray directly ahead slowly makes off as the skiff drifts closer. The next one is of a ray with its young – completely aware of us as we glide past to one side, but not especially bothered.

Southern Stingrays, Bahamas  (Keith Salvesen)Southern Stingray adult and young, Bahamas  (Keith Salvesen)

If you are swimming, snorkelling or diving, don’t get too close – especially by swimming directly over a ray (apparently Steve Irwin’s mistake, so that he was struck right in the chest by the stinger when the ray reacted).

Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

Enough of the potential dangers. The southern stingray is a magnificent creature, as Melinda’s wonderful photographs show. She spends half her life underwater and I’m not aware that she has had a problem with a ray. 

Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

Like many larger sea creatures, stingrays need help with their personal care – the removal of parasites, dead skin and so forth. And so they make use of the services offered by small fish like gobies, wrasses and shrimps at a CLEANING STATION. Here are 2 photos of rays doing just that. You can see the tiny fish by the reef, going about their work. There’s a mutual benefit in this symbiotic relationship, in which it is understood that the cleaners are unharmed. Indeed, they will often enter the mouths and gills of a fish to clean… including the teeth. So there’s dental hygiene on offer too…

Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

Southern Stingrays, Bahamas (Melinda Riger / Grand Bahama Scuba)

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Photo Credits: Melinda Riger / Grand Bahama Scuba, except for the feeding photo (cheers, Samantha Regan), the ‘specimen’ from Tomas Willems (Wiki) and my two noted above

CHRISTMAS TREE WORMS: SEASONAL SPIROBRANCHES


Christmas Tree Worm (Melinda Riger / Grand Bahama Scuba)

CHRISTMAS TREE WORMS: SEASONAL SPIROBRANCHES

music-notes-clip-art-png-musicDeck the Reefs with Worms Like Christmas Trees… Fal-La-La-etc-etc ” is a traditional Carol familiar to all. Well, most. Ok, some, then. Oh right – maybe with different words? Anyway, now is the perfect time to take another look at these remarkable subsurface symbols of seasonal good cheer (nb they are animals not plants).

christmas-tree-worm-melinda-riger-g-b-scuba

10 CHRISTMAS TREE WORM FACTS TO PONDER

  • The 2 colourful spirals are not the worm, but complex structures for feeding & respiration
  • The spirals act as specialised mouth extensions for ‘filter-feeding’
  • Prey is trapped by the feathery tentacles & guided by cilia (microscopic hairs) to the mouth
  • The tentacle things are radioles and act as gills for breathing as well as prey traps
  • It is not believed that prey slide down the spiral to their doom, like on a helter-skelter

Christmas Tree Worm (Neil Hobgood Wiki)Christmas Tree Worm (Melinda Riger / Grand Bahama Scuba)

  • The actual worm lives in a sort of segmented tube, with extremely limited mobility skills
  • It contains digestive, circulatory & nervous systems – and a brain in the middle of it all
  • The worm also has a tiny drainage tube (I think I have this right) for excretion etc
  • They embed themselves into heads of coral such as brain coral. And stay there
  • And yes, the Christmas trees are retractable… (see below for some action)

spirobranchus_giganteus_orange_christmas_tree_worm-nick-hobgood-wiki

HOW DO THE WORMS… YOU KNOW…  ERM… REPRODUCE?

This is a delicate area. They don’t tend to talk about it much, but as far as I can make out they eject gametes from their what-I-said-above. There are mummy and daddy worms, and their respective gametes (eggs and spermatozoa) drift in the current and presumably into each other to complete the union. The fertilised eggs develop into larvae, which settle onto coral and burrow into it, build their protective tubes and the process begins again.

christmas_tree_worm-nick-hobgood-wiki

YOU DON’T REALLY UNDERSTAND THESE CREATURES, DO YOU?

I won’t lie. I found it hard to work out how the CTWs function in practice. There are plenty of resources showing them in their full glory, but that only takes one so far. Then I came across a short video that shows it all brilliantly simply (except for the reproduction part).

The worms, in their coral burrows, hoist their pairs of ‘trees’. You can easily see small particles – possibly zooplankton – drifting in the water, and the radioles swaying to catch potential food. Suddenly it all makes sense (except the repro bit – I haven’t found footage of that).  Next: the New Year Worm (there is no Easter worm).

A WHOLE FESTIVAL OF CHRISTMAS TREE WORMSChristmas Tree Worms (Neil Hobgood Wiki)

Credits: Melinda Riger (G B Scuba); Nick Hobgood; Betty Wills; Video by ‘Super Sea Monkey’;Reef Collage by RH; MarineBio; Wikibits & Magpie Pickings

Happy Christmas to all those who put up with RH with such fortitude
blue_christmas_tree_worm-betty-wills-wiki