Imagine that you are swimming along resplendent in your snorkelling gear (me) – or in scuba gear for the advanced swimmer (you). There, below you, camouflaged against the sea bottom is a fish. A strange-shaped brown sort of creature with odd side fins. As it progresses over the gravelly sand, your immediate reaction is ‘what the…?’ Its fins seem to be turning into… wings. Like this:
Yes, it’s a flying gurnard. Unlike flying fish, it can’t actually fly through the air. But once its wings are fully spread, it certainly looks as though it could.
WHAT’S THE POINT OF THE WINGS IF THE THING CAN’T FLY?
This gurnard species usually gets around using its ventral fins as ‘legs’, with the pectoral fins (‘wings’) close to the body. There seem to be several possible reasons for possessing the ‘sudden-deployment-of-flashy-wings’ superpower.
It surprises and deters predators by movement, turning prospective prey into an apparently different creature
Bright or lurid colouring may be a deterrent warning of a foul-tasting or poisonous species (APOSEMATISM)
A creature may actually be harmless and even tasty (as here) but may appear to be unpalateable or poisonous(BATESIAN MIMICRY)
In any event, the wings enable the fish to take off from the sea bottom and travel faster by ‘flying’ thought the water to escape a predator
ROCK BEAUTY . Holacanthus tricolor . BAHAMAS REEF FISH
These creatures are a small species of angelfish. Seen swimming around the reefs they are unmistakeable, not least because of their bright yellow hi-viz jackets, remarkable blue eyeliner and blue-black lipstick.
Rock Beauties look like prime candidates for anyone’s aquarium, but they have picky dietary requirements and a tendency for aggression that make them unsuitable (fortunately for them).
They are highly specialised feeders, needing marine sponges in their daily diet. They are also prone to chase tank-mates and nip them. On balance, they look more fetching nosing about the coral anyway.
WHAT DO JUVENILES LOOK LIKE?
Juvenile rock beauties are cute mini-versions of the adults, only even more yellow and with yellow lips.
In development stages, they may have a vivid blue and black circle in front of the tail fin…
A spectacular entry in my WTF? series came courtesy of Adam Rees and a night dive in Florida waters: the guitarfish, (Gr: rhinos – nose; batis – ray) . Until I saw Adam’s photos, this creature was unknown to me. It sounded so improbable, and conjured up some nightmare piscine-based modification of a Strat, an instrument whose classic looks should not be meddled with without consequent loss of liberty.
The guitarfish belongs to a family of rays, Rhinobatidae, of which there are many species worldwide. In some ways the fish looks like a crossover with a shark. Although they have a ‘ray face’ and small wings, there is also a sharklike appearance with its fins and a sharklike swimming action (see video, below). If you think there is a primitive or prehistoric look to the guitarfish, you’d be right. According to the temporal range chart they date from the late Jurassic era.
I have been trying to nail the exact model of Adam’s finny Strat-ray. I am putting my money on the Atlantic guitarfish Rhinobatos lentiginosus, which may (or may not) be the same as the spotted or freckled; and is similar to the more widely photographed shovelnose guitarfish with its cute face. Not that I am very bothered: it’s the overall unusualness of Adam’s creature that really counts.
The strange thing is that although the guitarfish is a denizen of, for example, floridian, caribbean and mexican gulf waters, it is said to be unrecorded for the Bahamas. These bottom-feeding creatures inhabit shallower waters near coastlines and estuaries. They eat crabs, shellfish and worms – all in plentiful supply in Bahamas waters – so I can’t see a reason why they should not be found there. Perhaps they are seen but unreported. I have in mind the recent reports of SAWFISH and BATFISH. So kudos awaits the person who reports – with photo – the ‘first’ Bahamas guitarfish. Maybe there’s scope for a song about it!
Usually caught by mistake by anglers, or as bycatch by fishing vessels
Inedible (unless someone knows better…)
Non-aggressive and harmless to humans despite having a mouthful of small teeth
Swims like a shark – the tail has no spinal structure
Has a cute face (unlike a a shark)
Adults are about 30 inches long
They may bury themselves in sand or mud to ambush prey
They are viviparous, giving birth to live young that are born fully developed
As a postscript, it’s worth mentioning that on the same night dive, Adam also came across the uncommon batfish, a seriously prickly-looking starfish, and a spotted eagle ray. Worth losing sleep for.
A similar kind of guitarfish, showing the very sharklike movements in the water
Credits: Adam Rees, with many thanks; Greg Hume; Johan Fredriksson wiki; magpie pickings, in particular Florida Museum of Natural History / Taylor Sullivan and the truthful parts of various Wiki articles
The bluehead wrasse (or blue-headed wrasse) Thalassoma bifasciatum is a denizen of the coral reefs in the tropical waters of the western Atlantic Ocean. This bright little 4-inch fish is… a wrasse with a blue head. No more and no less. Unless it’s a juvenile. Then it is mainly bright yellow. It’s similar to BLUE TANG (aka ‘the Disney Dory’), which starts life bright yellow and grows up to be blue.
The species may be found singly, in pairs or small groups, or in schools. They have an important role to play in the life of the reef. They are CLEANER FISH, vital to the health and wellbeing of the larger species they attend to, and thus of the reef itself. This is ‘cleaning symbiosis’, a relationship of mutual benefit. The big fish get cleaned; the little fish have a useful function and – importantly for them – therefore don’t get eaten.
Having said that, blueheads are of course fair game as a snack for species that aren’t in the market for their cleaning services. Rather unfairly, some species that are quite content to let cleaner gobies pick around their gills and mouths are not so considerate of the wrasse (some types of grouper and moray eel, for example).
TELL US EXACTLY SEVEN BLUEHEAD WRASSE FACTS
Juveniles can alter the intensity of their colour, stripes & bars
The bluehead wrasse is a ‘protogynous sequential hermaphrodite’
All are born female**. Some change sex to male during maturation (see below)
Food includes zooplankton, small molluscs and small crustaceans…
…and parasites / other juicy bits (fungal growths, anyone?) from bigger fish
Main threats to the species are coral reef degradation / destruction and pollution
The bright colours invite aquarium use, but the trade in this species is not critical.
** Some sources suggest some are born male and remain male.
A juvenile bluehead – mostly yellow, with a pale underside
THE REMARKABLE SEX LIFE OF THE BLUEHEAD WRASSE
This is an unavoidable topic, I’m afraid. The bluehead’s sex life is the most interesting thing about them, and this is no time to be prudish. It has been the subject of extensive scientific research. As with many human relationships, “it’s complicated” but in a conch shell it boils down to this:
To recap, BWs are born female and as they mature, some become male.
Males reach an ‘initial phase’ when they can breed in groups with females
Some males grow larger & reach full colouration. This is the ‘terminal phase’
These large males aggressively chase away smaller ones & seek females to pair with
Their state of readiness is signalled by colour changes BUT the females know…
…that the smaller males have a sperm count higher than dominant males.
As the excellent organisation OCEANA puts it: Bluehead Wrasses may reproduce in four different ways throughout their lifetime: 1) as a female in a group spawning event; 2) as a female in a pair spawning event within the territory of a large male; 3) as a small male in a group spawning event; and 4) as a dominant, terminal male in a pair spawning event within its own territory.
A cropped still from a video I took at Fowl Cay marine reserve. I’ve looked at dozens of images online and not found one that was all blue with a yellow end to its tail fin. Perhaps it is just an all-blue alpha male.
Credits & Sources: Melinda Riger; Adam Rees; James St John; Oregon State edu / Pinterest; Wiki images; self; Oceana; IUCN; magpie pickings
FLAMINGO TONGUE SNAILS Cyphoma gibbous are small marine gastropod molluscs related to cowries. The living animal is brightly coloured and strikingly patterned, but that colour only exists in the ‘live’ parts – the so-called ‘mantle’. The shell itself is usually pale, and characterised by a thick ridge round the middle. Whether alive or as shells, they are gratifyingly easy to identify. These snails live in the tropical waters of the Caribbean and the wider western Atlantic.
THE IMPORTANCE OF CORAL
Flamingo tongue snails feed by browsing on soft corals. Often, they will leave tracks behind them on the coral stems as they forage (see image below). But corals are not only food – they provide the ideal sites for the creature’s breeding cycle.
Adult females attach eggs to coral which they have recently fed upon. About 10 days later, the larvae hatch. They eventually settle onto other gorgonian corals such as Sea Fans. Juveniles tend to live protectively on the underside of coral branches, while adults are far more visible and mobile. Where the snail leaves a feeding scar, the corals can regrow the polyps, and therefore the snail’s feeding preference is generally not harmful to the coral.
The principal purpose of the patterned mantle of tissue over the shell is to act as the creature’s breathing apparatus. The tissue absorbs oxygen and releases carbon dioxide. As it has been (unkindly?) described, the mantle is “basically their lungs, stretched out over their rather boring-looking shell”. There’s more to them than that!
THREATS AND DEFENCE
The species, once common, is becoming rarer. The natural predators include hogfish, pufferfish and spiny lobsters, though the spotted mantle provides some defence by being (a) startling in appearance and (b) on closer inspection by a predator, rather unpalatable. Gorgonian corals contain natural toxins, and instead of secreting these after feeding, the snail stores them. This supplements the defence provided by its APOSEMATIC COLORATION, the vivid colour and /or pattern warning sign to predators found in many animal species.
It comes as little surprise to learn that man is considered to be the greatest menace to these little creatures, and the reason for their significant decline in numbers. The threat comes from snorkelers and divers who mistakenly / ignorantly think that the colour of the mantle is the actual shell of the animal, collect up a whole bunch from the reef, and in due course are left with… dead snails and their allegedly dull shells Don’t be a collector; be a protector…
The photos below are of nude flamingo tongue shells. Until I read the ‘boring-looking shell’ comment, I believed everyone thought they were rather lovely… I did, anyway. I still do. You decide!
Image Credits: Melinda Rogers / Dive Abaco; Keith Salvesen / Rolling Harbour; Wiki Leopard
Thanks to all followers, likers, commenters, regular visitors, one-offs, local wildlife organisations, and friends of Rolling Harbour in general. This year we passed 1 million hits over the ten years of this blog. Proving that people love Abaco, the Bahamas, birds, marine mammals, manatees, reef fish, sharks, turtles, shore-life, shells, insects, plant life, bonefishing, lighthouses, local history, maps, conservation and a whole lot more; and are prepared to tolerate bad puns, haphazard presentation, and a less than rigourous scientific approach to it all.
Weirdest search term ever: How to dispose of dead bodies?
Painted Tunicates Clavina picta are one of several species of tunicate ‘sea-squirts’ found in Bahamas and Caribbean waters. These creatures with their translucent bodies are usually found clustered together, sometimes in very large groups. One reason for this is that they are ‘sessile’, unable to move from where they have taken root on the coral.
HOW DO THEY FEED?
Like most if not all sea squirts, tunicates are filter feeders. Their structure is simple, and enables them to draw water into their body cavity. In fact they have 2 openings, an ‘oral siphon’ to suck in water; and an exit called the ‘atrial siphon’. Tiny particles of food (e.g. plankton) are separated internally from the water by means of a tiny organ (‘branchial basket’) like a sieve. The water is then expelled.
WHAT DOES ‘TUNICATE’ MEAN?
The creatures have a flexible protective covering referred to as a ‘tunic’. ‘Coveringcates’ didn’t really work as a name, so the tunic aspect became the name.
IF THEY CAN’T MOVE, HOW DO THEY… (erm…) REPRODUCE?
Tunicates are broadly speaking asexual. Once a colony has become attached to corals or sponges, they are able to ‘bud’, ie to produce clones to join the colony. These are like tiny tadpoles and their first task is to settle and attach themselves to something suitable – for life – using a sticky secretion. Apparently they do this head first, then in effect turn themselves upside down as they develop the internal bits and pieces they need for adult life. The colony grows because (*speculation alert*) the most obvious place for the ‘tadpoles’ to take root is presumably in the immediate area they were formed.
APART FROM BEING STATIONARY & ASEXUAL, ANY OTHER ATTRIBUTES?
Some types of tunicate contain particular chemicals that are related to those used to combat some forms of cancer and a number of viruses. So they have a potential use in medical treatments, in particular in helping to repair tissue damage.
Credits: all fabulous close-up shots by Melinda Riger / Grand Bahama Scuba; diagram from depts.washington.edu; magpie pickings with a particular mention of an article by Sara MacSorley
There’s no doubt about it, barracudas have a particularly unwelcoming look to them. They exude menace. There’s something about the torpedo shape, the primitive head, and the uncomfortably snaggle-toothed grin-with-underbite that suggests a creature not to be underestimated.
And that smiley mouth – rather scornful and derisive, is it not? A powerful creature in its element, where you are the intruder… and it sees it like that too. An adult barracuda may grow to nearly 6 foot long. Your are only temporarily of its world, and (it observes) you are keeping your distance.
The dental arrangements of a ‘cuda are a wonder in themselves. The teeth are razor sharp; an orthodontist’s nightmare because they are all different sizes and grow at different angles. Some are conventionally set in the jaws, but some actually grow from the roof of the mouth. There are ‘normal’ sized teeth interspersed with wicked-looking fangs that randomly grow facing forwards, backwards and sideways.
WHY THE UNTIDY MOUTH FURNITURE?
The name Barracuda is thought to derive from the Spanish word barraco meaning (in one of its senses) “overlapping teeth”. The jaws that contain the teeth are strong, and the underbite adds to the effectiveness of ‘cuda predation. Prey is highly unlikely to escape once caught. When the jaws snap shut, the sharp angled teeth – particularly the back-facing ones (cf fishhook barbs) prevent the victim from pulling away. Then the munching and shredding can begin inside what is essentially a perfectly equipped multi-bladed mincing machine.
Manatees are apex ‘gorgeous marine mammals’. Gentle, inquisitive, brave, long-distance-but-rather-slow-swimming, grass-grazing miracle ur-elephant descendants. They never made it out of the sea in the Miocene epoch.
Incongruous in a world of fast sharks, snappy ‘cudas, large whales and leaping dolphins, they contentedly mooch around the seagrass beds. No one in the world has ever objected to or dissed a manatee. They bring only delight to the sea-world, and offer only charm to mankind.
In the past, I’ve written about the small number of manatees that inhabit the turquoise inner waters of the Bahamas. They were carefully recorded with individual identifying features – usually nicks in the paddle, or scarring. Usually they were named and, where possible, fitted with a tracker. Their friendships and amorous hook-ups were noted. Despite a 16-month birth cycle, manatee-lets were born. Then Dorian struck, and the situation for manatees (as with many other creatures) became unclear. The good news is that they are now increasingly sighted, with photos taken and soc med posts to admire.
IS THERE A DOWNSIDE FOR THESE APPARENTLY BLISSFUL AND PEACEFUL CREATURES?
Yes indeed. It’s mankind, I’m afraid. Among the threats to the survival of these unusual, endearing, and legally protected creatures are, in no particular order:
Pollution of inshore waters and canals
Degradation of the (formerly limitless) sea-grass beds where they feed
Reduction or tainting of the fresh water sources that they need to survive
Understandable over-enthusiasm by admirers – especially in harbours – in dousing them with water from hoses and feeding them lettuce…
…and similar behaviours that may lead to a trusting dependance on humans
Unthinking or speed-selfish boat behaviour in or near harbours resulting in collisions
Simply not caring at all and carving them up, leaving often deep prop-scars. Few manatees escape at least a few of these. Some do not survive.
Probably I don’t need to mention man-caused Global Warming, but I just have.
Let’s celebrate this special month for manatees. Let’s hope that they can survive and prosper in these increasingly difficult and dangerous times for almost all species. Look at any of these photos… can we agree that these wonderful animals deserve care and protection.
All photos: Charlotte Dunn / BMMRO and research contributors; final image ‘Save the Manatee’
Larger reef fish tend to get more attention than the tiddlers, for obvious reasons. Yet a reef would not properly exist without the small fish that drift and wriggle round the corals. Blue chromis (Chromis cyaneus) are among the first reef fish species I ever met when snorkelling at Fowl Cays.*
Blue chromis belong to the same group as damselfishes. These unmistakeable, bright reef denizens are very visible despite their tiny size. These fish are shoalers, so out on the reef you can enjoy them flickering around you as you swim along or hang in the water to admire the corals.
Like many a pretty and easily captured small fish that can be monetised once removed from its natural home environment, the blue chromis is popular for aquariums. Humans like to keep them in their own home environments safely away from oceans and reefs, unselfishly feeding the little things concocted food to keep their little lives going till the cat gets them. [Sorry, I don’t know what came over me there]
Blue chromis are adaptable and sociable, and will happily swim with other small reef fishes (as above). My own favourite combo is chromis mixed in with sergeant majors. But a shoal of them (mostly) alone is pretty special too….
I cynically mentioned ‘concocted’ food earlier. Here is one online care instruction for looking after them: “They are omnivores, meaning that they eat both meaty and plant based foods. They are not difficult to feed and will eat a variety of regular aquarium fare, frozen, live, and sometimes even dry food. Feeding them a variety of foods will help them retain their color in captivity. They sometimes feed on the algae in the tank”. So I think it’s ok to suggest that leaving the fish out on the reef might suit them better.
If tempted to ‘rescue’ some from their reef habitat, rest assured that they have been known to spawn in captivity. Blue chromis can usually be obtained for about $10-15. And don’t hold back on the frozen food (though maybe warm it up a bit before feeding time). I rest my case.
*I say ‘snorkelling’ rather than anything more impressive because I am a pathetic swimmer and I know my limitations…
Credits: Melinda Rodgers / Dive Abaco; Melinda Riger / G B Scuba
I featured the extraordinary, colour-transforming PEACOCK FLOUNDER Bothus lunatus a while back as part of a Bahamas Reef Fish series. These really are remarkable creatures, and I have decided to return to them mainly because of the wonderful illustrative photos I was able to incorporate. There are plenty of flounder facts too, but if you just enjoy the pictures and skip the blurb I’ll understand.
In the fish shown here, you’ll see that – surprisingly – both eyes are on the upper-side of the fish, above the rather grumpy mouth, whereas the head is horizontal to the ocean floor. Oddest of all, juveniles are constructed conventionally with bilateral eyes, and look like ‘normal’ fish rather than flatfish.
As the fish matures, in some magic way the mechanics of which I can only guess at**, the right eye grows round to the topside and the flounder transforms from a ‘vertical’ fish to a flatfish. For this reason, the PF is known as a ‘left-eye’ flounder. Maybe in other flounder species in the world – the southern hemisphere maybe? – the eye that moves round to the upper-side is the left eye.
The eyes of this fish have another special trick up their sleeves (so to speak). They operate completely independently. Thus the creature can look left and right, or forwards and backwards, simultaneously. It’s an excellent system for detecting predators coming from any angle. It’s a superpower we might all benefit from.
DO THEY HAVE ANY OTHER TRICKS WE SHOULD KNOW ABOUT?
Yes they do indeed. If you have been admiring the fish shown so far, you’ll have noticed that the colour of each one differs from the others. In addition to the predator-protection that the eyes provide, the peacock flounder can make itself (near) invisible. They can rapidly change colour to match their surroundings. There are 3 reasons for this: to avoid / confuse predators; to conceal themselves on the sea-floor to catch passing prey; and, as dive expert Fred Riger has pointed out, “the male peacock flounder can, and does greatly intensify his colours to declare territory and attract females. When doing this the males will also signal with the left pectoral fin, sticking it straight up and waving it around.”
The same fish, photographed over several minutes as it moves over the ocean floor
Matching the background happens as the fish swims, and in a few seconds. When they rest on the sea-floor, the camouflage may even become total. In #4 above you can just about make out the eyes. The whole effect is known as ‘cryptic coloration’ or CRYPSIS. In contrast, the image below shows just how adaptable the transformation can be. Note how the fish can even mimic the pinkish tinge of the sand perfectly. If threatened, the fish will bury itself in the sand, with just its eyes showing.
HOW DO THEY MANAGE TO CHANGE COLOUR IN SECONDS?
It’s complicated! A simple answer is: a mix of hormones, pigment-cells and vision, all coordinating rapidly. The colour change works in two ways: pigments are selectively released to the skin cells; and other pigments can be selectively suppressed. An analogy might be image manipulation using variations in brightness, saturation etc. Not convinced? Then watch this short video and prepare to be impressed. Astonished, even.
WHAT IF A FLOUNDER CAN’T SEE CLEARLY FOR SOME REASON?
As with many (all?) superpowers, there is usually some kryptonite-style flaw. A flounder with a damaged eye, or one temporarily covered (by sand, for example) will have difficulty in changing colour – possibly at all, or at any rate with the swiftness it needs to have.
THESE SIDEWAYS FISH – HOW DO THEY… YOU KNOW…?
Take a look at the fish above with its top fin raised. It’s a ‘ready’ signal in a harem. Male flounders have a defined and defended territory within which live up to 6 females – a so-called ‘harem.’ I can do no better than borrow the description of the rituals from an article derived from scientific papers byKonstantinou, 1994; Miller, et al., 1991in the websiteanimaldiversity.org/…ounts/Bothus_lunatusTo which I can only add, ’15 seconds, eh?’
“Mating activities usually begin just before dusk. At this time, a male and a female approach each other with the ocular pectoral fin erect. The two fish arch their backs and touch snouts. After this interaction the female swims away, and the male sometimes follows, approaching the female again from the left side. At this point the male pectoral fin is erect and the female pectoral fin moves up and down, possibly signalling willingness to mate. The male then positions himself underneath the female and mating begins. This process consists of a mating rise, during which the female and male rise in the water column together. On average, these rises last about 15 seconds. At the highest point of this rise, usually around 2 m above the substrate, gametes from both fish are simultaneously released, producing a cloud of sperm and eggs. Once the couple returns from the rise, the male “checks” to make sure mating was successful, and the pair separates quickly, swimming away from each other in opposite directions. Not all mating rises are successful, and the process of “checking” is thus important. The exact purpose of the mating rise in these flounders unknown; possible reasons for rising include better dispersal of gametes and predator avoidance.”
Peacock Flounder – Kim Rody Art
**This may in fact have been through sheer laziness
Credits: Melinda Riger & Virginia Cooper / Grand Bahama Scuba; Melinda Rogers / Dive Abaco; Adam Rees / Scuba Works; Kim Rody; animaldiversity.org; magpie pickings and other credits in the text
The most apposite description of brain coral Diploria labyrinthiformisis is essentially a no-brainer. How could you not call the creatures on this page anything else**. These corals come in wide varieties of shape and colour, and 4 types are found in Caribbean waters. They date from the Jurassic period.
Each ‘brain’ is in fact a complex colony consisting of genetically similar polyps. These secrete CALCIUM CARBONATE which forms a hard carapace. This chemical compound is found in minerals, the shells of sea creatures, eggs, and even pearls. In human terms it has many industrial applications and widespread medicinal use, most familiarly in the treatment of gastric problems.
The hardness of this type of coral makes it an important component of reefs throughout warm water zones world-wide. The dense protection also guarantees (or did until our generation began systematically to dismantle the earth) – extraordinary longevity. The largest brain corals develop to a height of almost 2 meters, and are believed to be several hundred years old.
HOW ON EARTH DO THEY LIVE?
If you look closely at the cropped image below and other images on this page, you will see thousands of tiny tentacles nestled in the trenches on the surface. These corals feed at night, deploying their tentacles to catch food. Their diet consists of tiny creatures and their algal contents. During the day, the tentacles retract into the sinuous grooves. Some brain corals have developed tentacles with defensive stings.
THE TRACKS LOOKS LIKE MAZES OR DO I MEAN LABYRINTHS?
The difference between mazes and labyrinths is that labyrinths have a single continuous path which leads to the centre. As long as you keep going forward, you will get there eventually. You can’t get lost. Mazes have multiple paths which branch off and will not necessarily lead to the centre. There are dead ends. Therefore, you can get lost. Or never get to the centre at all.
** On the corals shown here, you will get lost in blind alleys almost at once. Therefore in human terms these are mazes. The taxonomic labyrinthiformisis is Latin derived from Greek, and applied generally to this kind of structure, whether in actual fact a labyrinth or a maze.
CREDIT: all amazing underwater brain-work thanks to Melinda Rogers / Dive Abaco; Lucca Labyrinth, Keith Salvesen / Rolling Harbour
Here is a beautiful inscribed labyrinth dating from c12 or c13 from the porch of St Martin’s Cathedral in Lucca, Italy. Very beautiful but not such a challenge.
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. From now on and through the summer would be a good time to investigate.
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.
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 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 & a different one to a squid on its other side
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 playing 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)
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. **
SQUID SEX (2) IT ALL ENDS BADLY. VERY BADLY.
As soon the female squid has laid her eggs, she usually dies soon after
Male squid live 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 in the end (but there’s no romantic balcony scene first)
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 possibly say ‘I collect both reef and giant squids’. “Squidses” sounds fun but is sadly not permitted.
** For an excellent article about squid including the intricate details of courtship and reproduction (and an image of a squid penis) check out SQUID WIKI
Credits: Fabulous underwater pics – Melinda Riger of Grand Bahama Scuba; research sources include MarineBio; Animal Diversity Web (Michigan Uni); and Wiki, which comes into its own in some fields of natural history where experts write the entry)
FAIRY BASSLET (‘MIND YOUR GRAMMA’): BAHAMAS REEF FISH (33)
The Fairy Basslet is a tiny brightly-coloured fish with a pretentious alternative name. It is otherwise known as the Royal Gramma (Gramma loreto). These fish are found in the coral reefs of the (sub)tropical western Atlantic. They are also found in aquariums anywhere you like, being small, bright, placid and generally good-natured.
Conveniently, the basslet is unlikely to be confused with any other species. Its striking two-tone colour scheme of purple and yellow is hard to miss. The purple front half (which is presumably where the ‘royal’ comes from, being a regal or imperial colour) may also be violet or even blue in some fish and / or in some light conditions. Another identification pointer is a black spot on the dorsal fin.
You’ll notice that the basslet above appears to be upside down. Which is because it is – this isn’t an inadvertent photo-flip. These little fish tend to orientate themselves to be parallel with the closest surface. This leads to them happily swimming upside down, or aligning vertically. As one article I read says severely, “this behaviour is not to be mistaken for illness”.
Fairy basslets / royal grammas are also CLEANER FISH. They pick parasites and dead skin off larger fish that visit so-called cleaning stations to be attended to by tiny fish and cleaner shrimps, and in some instances to have their gills and even their teeth cleaned. The deal is that, in return, the large fish do not eat the cleaners. Even snack-sized ones rootling around inside their mouths.
WHAT ABOUT BREEDING?
I really can’t improve on this rather touching description from Wiki: “The male will build the nest among rocks using pieces of algae.The male will then lead the female to the nest, where she will deposit 20-100 eggs in the nest. During the breeding period, this behaviour is repeated almost every day for a month or longer (my italics). The eggs are equipped with small protuberances over the surface with tiny threads extending from them which hold onto the algae of the nest and keep the eggs in place. The eggs will hatch in five to seven days, normally in the evening…”
HOW COME THE NAME ‘GRAMMA LORETO’?
This official name became a brainworm with me after I started this post. I had to check it out. The ‘Gramma’ part is unrelated to the fond name for a grandmother; rather, it simple denotes a member of the genus of fishes in the family Grammatidae.
The Loreto part is more mysterious. It is an an ancient town in Italy; and the name of several British schools, including – almost too good to be true – a school called Loreto Grammar. In a nutshell, the link between the town and places of education is that the Sisters of Loreto, founded in the c17 and named for a shrine in the Italian village, are dedicated to education in their Ministry.
How that ties in with a tiny Caribbean reef fish, I have yet to find out. I probably never will… Here’s a short video to alleviate the disappointment.
I failed to be able to resist finding out whether any country of the world has a purple and yellow flag. The answer is, no. However I am delighted to be able to report that the flag of the Independent Party of Uruguay is basslet-coloured.
Credits: all fantastic photos by Melinda Riger of Grand Bahama Scuba; magpie pickings of an unacademic sort for facts and speculation
ELKHORN CORAL (Acropora palmata) is a widespread reef coral, an unmistakeable species with large branches that resemble elk antlers. The dense growths create an ideal shady habitat for many reef creatures. These include reef fishes of all shapes and sizes, lobsters, shrimps and many more besides. Elkhorn and similar larger corals are essential for the wellbeing both of the reef itself and also its denizens. These creatures in turn benefit the corals and help keep them in a healthy state.
Examples of fish species vital for healthy corals include several types of PARROTFISH, the colourful and voracious herbivores that spend much of their time eating algae off the coral reefs using their beak-like teeth. This algal diet is digested, and the remains excreted as sand. Tread with care on your favourite beach; in part at least, it will consist of parrotfish poop.
Other vital reef species living in the shelter of elkhorn and other corals are the CLEANERS, little fish and shrimps that cater for the wellbeing and grooming of large and even predatory fishes. Gobies, wrasse, Pedersen shrimps and many others pick dead skin and parasites from the ‘client’ fish including their gills, and even from between the teeth of predators. This service is an excellent example of MUTUALISM, a symbiotic relationship in which both parties benefit: close grooming in return for rich pickings of food.
VULNERABILITY TOCLIMATE CRISIS
Formally abundant, over the course of just a couple of decades elkhorn coral (along with all reef life) has been massively affected by climate change. We can all pinpoint the species responsible for much of the habitat decline and destruction, and the primary factors involved. In addition, global changes in weather patterns result in major storms that are rapidly increasing in both frequency and intensity worldwide.
Physical damage to corals may seriously impact on reproductive success: elkhorn coral is no exception. The effects of a reduction of reef fertility are compounded by the fact that natural recovery is in any case inevitably a slow process. The worse the problem gets, the harder it becomes even to survive, let alone recover, let alone increase.
HOW DOES ELKHORN CORAL REPRODUCE?
There are two types of reproduction, which one might call asexual and sexual:
Elkhorn coral reproduction occurs when a branch breaks off and attaches to the substrate, forming a the start of a new colony. This process is known as Fragmentation and accounts for roughly half of coral spread. Considerable success is being achieved now with many coral species by in effect farming fragments and cloning colonies (see Reef Rescue Network’s coral nurseries)
Sexual reproduction occurs once a year in August or September, when coral colonies release millions of gametes by Broadcast Spawning
All photos: Melinda Rogers, with thanks as ever for use permission
I have just been lightly involved in a long online thread showcasing the weirdest / most science fiction-y creatures around the world. Trust me, there are plenty. There were quite a few duplications. My own contribution was the frogfish, which no one else had nominated. They are so special – and so weird – that I am reposting my article about them. Don’t miss the last video!
This ‘WTF?’ series started with a relatively conventional species, the REMORA. It has been getting progressively more bizarre. We moved onto an omnium gatherum of WEIRDO FISHES, then the remarkable LETTUCE SEA SLUG, and most recently the BATFISH. Time to ramp up the stakes: with many thanks to scuba expert Adam Rees for use permission for his terrific photos, I present… the FROGFISH.
The frogfish is a kind of anglerfish found in almost all tropical and subtropical oceans and seas. There are about 50 different species worldwide, covering an astonishing range of strange appearances. They generally live on the sea floor around coral or rock reefs. In size they vary from tiny to about 15 inches long – although ‘long’ is a flexible concept because they are to an extent shape-changers in height and width.
FROGFISH SUPERPOWERS YOU MAY WISH TO HAVE
INVISIBILITY CLOAK . Frogfish are masters of disguise and camouflage. This enables them to catch their prey with minimal effort and also to avoid predators. Their camouflage methods – broadly known as ‘aggressive mimicry’ – include
Ability to change colour for days or even weeks to mimic their surroundings
Getting covered in algae and other organic matter that matches their habitat or
Looking inherently like a plump rock or in some cases, plant
Fear for the life of the spider crab…
A sort of frontal dorsal fin called an illicium to which is attached a
Lure called an esca which may mimic a worm, shrimp or small fish etc and which is
Retractable in many species and
Regenerates if it gets mislaid
The ‘dollop of cream’ thing is the esca. Note the characteristic large mouth
Spot the esca…
BUOYANCY CONTROL & SHAPE-SHIFTING
Most frogfish have a ‘gas bladder’ to control their buoyancy.
Some species can change shape or even inflate themselves by sucking in quantities of water in a so-called defensive ‘threat display’.
HOW DO FROGFISH REPRODUCE?
Although not conventionally attractive creatures, frogfish clearly manage to reproduce. Little is known about the techniques in the wild, but one is probably ‘with care’, especially for a male frogfish who may not survive for long if he hangs around after fertilisation has taken place. It has been noted that females tend to select far smaller males to fertilise their huge numbers of eggs, perhaps for that very reason.
FROGFISH FEEDING SKILLS – GOOD OR BAD?
When deploying the lure, potential prey that comes too close to that wide mouth stands no chance. A frogfish will strike in a fraction of a second. Frogfishes have voracious appetites for crustaceans, other fish, and even each other. I can do no better than borrow this vivid description of a feeding frogfish:
“When potential prey is first spotted, the frogfish follows it with its eyes. Then, when it approaches within roughly seven body-lengths, the frogfish begins to move its illicium in such a way that the esca mimics the motions of the animal it resembles. As the prey approaches, the frogfish slowly moves to prepare for its attack; sometimes this involves approaching the prey or “stalking” while sometimes it is simply adjusting its mouth angle. The catch itself is made by the sudden opening of the jaws, which enlarges the volume of the mouth cavity up to twelve-fold, pulling the prey into the mouth along with water. The attack can be as fast as 6 milliseconds. The water flows out through the gills, while the prey is swallowed and the oesophagus closed with a special muscle to keep the victim from escaping. In addition to expanding their mouths, frogfish can also expand their stomachs to swallow animals up to twice their size.“
HOW DO FROGFISHES GET AROUND? SWIM? WALK? CRAWL?
Frogfishes do not in fact move around a great deal. Using their camo advantages, they prefer to lie on the sea floor and wait for prey to come to them. As mentioned in the quote above, they may slowly approach prey using their pectoral and pelvic fins to “walk” along the sea bottom. They can swim using their tail fin (or in some species by simple ‘jet propulsion’ by forcing water out of their gills) but rarely do so – they don’t feed on the move, and they are adapted to the sea floor environment where they food is readily available. However their “walking” ability is limited to short distances.
DO FROGFISH HAVE OTHER COLOUR SCHEMES?
Indeed they do. In stark contrast to the camo species, some frogfishes are highlighter bright. Here are two of my favourite photos by Adam that show this clearly. I’ve no idea if these are a male and female. I suspect they are different species. I think the brown one is a striated frogfish and the other is… a yellow frogfish. Some people keep these creatures in aquaria, but apparently it is impossible to sex them, and they have to be kept on their own for everyone’s peace of mind…
These two videos, from Lester Knutsen and Daan Van Wijk respectively, show some of the characteristics I have written about above. Both are short and both are fascinating.
To read more about frogfishes and for some fabulous photos I highly recommend the websiteFROGFISH.CHYou can reach the main page(s) but the link seem to be broken so I have not been able to contact Teresa Zubi, whose site it is. She clearly has a sense of humour and uses a neat pair of gifs which I hope she won’t mind my using…
Credits: All main photos, Adam Rees of Scuba Works with many thanks; wiki for ‘spot the esca’, red quote & basic info; videos Lester Knutsen & Daan Van Wijk; Teresa Zubi for website & gifs; infographics, authors u/k
After many decades of the savage depletion of the global whale population, the tide turned in their favour in the 1960s. It was fair to assume that, gradually, a new era of cetacean recovery must follow and that whales would be accorded the respect they deserve. Over time, many organisations were formed with the specific aim of protecting and conserving marine mammals, theBahamas Marine Mammal Research Organisation (BMMRO)based on Abaco among them.
The struggle to fulfil that aim in the face of entirely man-made environmental damage has become increasingly difficult. However, there have more recently been encouraging reports of population recovery in some seas, a good reason to celebrate WORLD WHALE DAY and to consider supporting the many organisations that work to preserve marine mammals.
The photographs and the 2 very moving videos below are of an adult sperm whale and new-born calf. They were taken by BMMRO in Bahamas waters. There’s optimism in these images. I’d like to think that a smiling baby whale holds out hope for the future. Hopefully it will flourish and live for decades. If it does not, the overwhelmingly likely cause will be mankind, either directly or indirectly.
CREDITS: Close-up footage plus the clips I have taken from it – Charlotte Dunn / Diane Claridge / BMMRO
DONATE: If you are touched by the magic of this little Bahamas sperm whale, may I invite you to consider making a donation to BMMRO for its research and conservation work – a scientific commitment that reaches far beyond the waters of the Bahamas. The system is set up to process donations from just $10 upwards, and every cent is used to further the work of BMMRO. Please click the logo below to reach the right page directly.
It is a rather special and indeed specialist day today: it is #spongethursday, a component of the 11th World Sponge Conference (I’d add the logo, but it closely resembles a pink Covid symbol). Poriferaphiles everywhere should be celebrating these beautiful creatures today. Here are some gorgeous examples. Now you know why sponges deserve a day of their own.
Candelabra Songe (with brittle stars attached)
Black Ball Sponges
One for Valentine’s Day
Spawning Brown Encrusting Sponge
All photos: Melinda Riger, Grand Bahama Scuba – with thanks as ever
As everyone knows, Hermit Crabs get their name from the fact that from an early age they borrow empty seashells to live in. As they grow they trade up to a bigger one, leaving their previous home for a smaller crab to move into. It’s a benign** chain of recycling that the original gastropod occupant would no doubt approve of, were it still alive… The crabs are able to adapt their flexible bodies to their chosen shell. Mostly they are to be found in weathered (‘heritage’) rather than newly-empty shells for their home. [**except for fighting over shells]
HERMIT CRAB FACTS TO ENLIVEN YOUR CONVERSATION
The crabs are mainly terrestrial, and make their homes in empty gastropod shells
Their bodies are soft, making them vulnerable to predation and heat.
They are basically naked – the shells protect their bodies & conceal them from predators
In that way they differ from other crab species that have hard ‘calcified’ shells / carapaces
Ideally the shell should be the right size to retract into completely, with no bits on display
As they grow larger, they have to move into larger and larger shells to hide in
As the video below shows wonderfully, they may form queues and upsize in turns
Occasionally they make a housing mistake and chose a different home, eg a small tin
The crabs may congregate in large groups which scatter rapidly when they sense danger
The demand for suitable shells can be competitive and the cause of inter-crab battles
Sometimes two or more will gang up on a rival to prevent its move to a particular shell
HERMIT CRABS CAN EVEN CLIMB TREES – WITH THEIR SHELLS ON TOO
HERMIT CRABS EXCHANGING HOMES with DAVID ATTENBOROUGH
This is a short (c 4 mins) extract from BBC Earth, with David Attenborough explaining about the lives and habits of these little crabs with his usual authoritative care and precision . If you have the time I highly recommend taking a look.
Credits: All photos taken on Abaco by Keith Salvesen except for the tree-climber crab photographed by Tom Sheley; video from BBC Earth
The Cookiecutter shark Isistius brasiliensis (aka the less scary, more genial sounding ‘cigar shark’), might be an ideal candidate for a Room 101 nemesis.** These little beasts – a species of dogfish shark – are found in several mainly island-based areas dotted around the globe, including in Bahamas waters.
HOW COME THE NAME?
These sharky little b@st@rds (*scientific term*) attack marine mammals and fishes, attaching themselves by suction and gouging out perfect round plugs of skin and flesh, leaving what are sometimes called ‘crater wounds’. Then they eat them. Imagine getting hold of a really sharp domestic cookie cutter with circular rows of razor-sharp teeth, and grinding it hard into your thigh. There! That!
The size of an adult shark:16″ max
The term ‘cookiecutter’ is also a pejorative slang term, meaning mass-produced, lacking in originality, or boringly samey, as in cookiecutter cars or TV genres etc. The little critters under consideration here are anything but…
HORRIFYING COOKIECUTTER FACTS
Live in the depths, rise vertically in the day & dive back down at dusk
Undersides have light-emitting ‘photophores’ which emphasise…
…the dark collar which acts as a lure, resembling a small innocent fish
Bioluminescence lures prey & confuses predators (more on this below)
The glow is so strong it may last for some time after removal from water
Their lips are ‘suctorial’ = they attach tightly to their target
The jaws then gouge out the victim’s flesh in a remarkably neat circle
Omni-vicious: any medium to large ocean creature is vulnerable to attack
There are even occasional reports of humans being targeted
Here are two Blainville’s beaked whales that I photographed from the BMMRO research vessel. The top whale has a number of circular healed attack marks and a recent one. You can see how deep the gouged hole is. The other has well-healed scars.
Multi-toothed: top rows of small teeth, rows of larger teeth on the bottom
The lower teeth are the cutters, acting like a saw when locked on
See header image and below for full details
HOW EXACTLY DO THEY DO WHAT THEY DO?
I can explain it no better than the renowned authority Prof. W. K. P. Dear: “the suctorial lips ensure a tight seal. It then bites, using its narrow upper teeth as anchors while its razor sharp lower teeth slices into the prey. Finally, the shark twists and rotates its body to complete a circular cut, quite possibly aided by the initial forward momentum and subsequent struggles of its prey. The action of the lower teeth may also be assisted by back-and-forth vibrations of the jaw, a mechanism akin to that of an electric carving knife”.
ARE THESE SHARKS ‘PARASITES’, WOULD YOU SAY?
The behaviour of these sharks is an example of a symbiotic relationship between two species that is parasitic. This means essentially that one gains and the other suffers (eg humans & no-see-ums). This is distinct from commensalistic symbiosis, where one species gains and the other is unaffected (e.g. cattle egrets with cattle); and mutualistic symbiosis, where both gain (e.g. cleaner fish & groupers). So, in a word, yes.
An ‘ambush predator’: these little sharks ‘hover’ in the water column waiting…
They are capable of rapid movement to catch up & latch onto prey
They will eat a passing small fish, crustacean or even squid as a snack
Sometimes they operate in schools; there is safety in numbers
The schools are thought to increase the ‘lure’ effect of the dark collar
A beached whale that’s been heavily targeted
FUN FACT TO COUNTERACT THE BAD STUFF
In the late c20, more than 30 U.S. Navy submarines were forced back to base to repair damage caused by cookiecutter shark bites, either to the neoprene footings of sonar domes or to rubber-sheathed cables. The problems were solved by using fibreglass. Oceanographic equipment and telecommunications cables are also recorded as being damaged by these sharks.
Cookiecutter Shark – the real deal
MONSTERS OF THE DEEP
These great cards from the weirdly spelledWIERD ‘N’ WILD CREATURESprovide excellent factual info. Their CCS card is no exception. You’ll find more details here about the effect of the bioluminescence and so on, written as clearly as I might hope to.
**“The worst thing in the world varies from individual to individual. It may be burial alive or death by fire, or by drowning, or by impalement, or fifty other deaths. There are cases where it is some quite trivial thing, not even fatal.” (George Orwell, 1984). Being in a tank with some cookiecutters might count.
Alright now… the wounds eventually heal
Credits: BMMRO – header image; beaked whale photos – Keith Salvesen / BMMRO; Te Ara NZ for the main jaw image; all small images with thanks to Wiki and respective photographers who took the time to upload them for all to enjoy & learn from; ‘wierdnwonderful creatures’ for the monster card; range map from Wiki
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