PEACOCK FLOUNDERS REVISITED: NOW YOU SEE THEM…


Peacock Flounder (Melinda Riger / G B Scuba)

        PEACOCK FLOUNDERS (Part Deux)

MASTERS OF SUBAQUATIC CAMOUFLAGE

I featured the extraordinary, colour-transforming PEACOCK FLOUNDER Bothus lunatus about 3 years ago in the Bahamas Reef Fish series (No. 21 I think). These really are remarkable creatures, and I am pleased to be able to show some more wonderful illustrative photos. 

Peacock Flounder (Melinda Riger / G B Scuba)

ROVING EYES

In the fish shown here, you’ll see that – surprisingly – both eyes are on the upperside 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.

Peacock Flounder (Melinda Rogers / Dive Abaco)

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 ‘lefteye’ flounder. Maybe in other flounder species in the world – the southern hemisphere maybe? – the eye that moves round to the upperside is the left eye.

Peacock Flounder (Virginia Cooper / G B Scuba)

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.

Peacock Flounder (Melinda Rogers / Dive Abaco)

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 floorPeacock Flounder (Wiki)

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.

Peacock Flounder (Melinda Rogers / Dive Abaco)

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 pignments 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. 

Peacock Flounder (Melinda Riger / G B Scuba)

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 by Konstantinou, 1994Miller, et al., 1991 in the website animaldiversity.org/…ounts/Bothus_lunatus To which I can only add, ’15 seconds, eh?’

Peacock Flounder (Melinda Riger / G B Scuba)

“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 ArtPeacock Flounder (Kim Rody Art))

**This may in fact be 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

Peacock Flounder (Melinda Riger / G B Scuba)

SUBMARINE SUPERMODELS: POUTS & GLAM EYES OF BAHAMAS REEF FISH


SUBMARINE SUPERMODELS

THE POUTS & GLAM EYES OF BAHAMAS REEF FISH

I have been idly filing away some stunning close-up reef denizen images by Melinda Riger. A Monday morning is the perfect time to showcase some pouts, poses and glad eyes from the ‘catfish walk’, starting with my absolute favourite…

A COWFISH** PERFECTS THE POUTCowfish ©Melinda Riger @ Grand Bahama Scuba

A GREEN MORAY EEL SMILES STRAIGHT TO CAMERAGreen Moray Eel ©Melinda Riger @ Grand Bahama Scuba copy

THE QUEEN ANGELFISH ‘LOVES’ THE LENSQueen Angelfish © Melinda Riger @ G B Scuba

A GROUPER DOES THE ‘OPEN-MOUTH’ GAPE'Bruno' ©Melinda Riger @ G B Scuba copy

THIS SCHOOLMASTER SNAPPER MAY NOT HAVE GOT QUITE WHAT IT TAKESSchoolmaster Snapper ©Melinda Riger GB Scuba copy 

NICE EYES, BUT THE PETITE SAND-DIVER NEEDS TO BE A LITTLE MORE OUTGOINGSand Diver Fish copy

AS DOES THE SOUTHERN STINGRAYSouthern Stingray ©Melinda Riger @ GB Scuba copy

HOWEVER THE PEACOCK FLOUNDER IS ROCKING THE MAKE-UP BOXPeacock Flounder Eye ©Melinda Riger @ G B Scuba copy

THE OCTOPUS IS MOODY &  WON’T GET OUT OF BED FOR LESS THAN 20 MOLLUSCSOctopus ©Melinda Riger GB Scuba copy

AND REGRETTABLY THE POOR CONCH HAS A BAD STAGE FRIGHTConch Eyes ©Melinda Riger @ Grand Bahama Scuba copy 2

For more octopus information and a discussion of the correct plural (choice of 3) CLICK HERE

For a post about underwater species camouflage CLICK HERE

**Since I posted this earlier today, I have been asked (re photo 1) what the… the… heck a Cowfish looks like, when it’s not puckering up while facing you. The answer is: stunningly glamorous…

Cowfish ©Melinda Riger @ Grand Bahama Scuba copy

Thanks as ever to Melinda Riger of Grand Bahama Scuba for use permission for her fab photos; tip of the dorsal fin to Wiki for the shark eye header pic

MASTERS OF UNDERWATER CAMOUFLAGE: BAHAMAS REEF FISH (7)


BAHAMAS MASTERS OF UNDERWATER CAMOUFLAGE

SCORPIONFISHScorpionfish camouflaged against coral ©Melinda RigerScorpionfish Close-up ©Melinda Riger @GBS

PEACOCK FLOUNDER or PLATE FISH Bothus lunatusPeacock Flounder Peacock FlounderPeacock Flounder ©Melinda Riger @ GB ScubaPhotos: Melinda at Grand Bahama Scuba

This is my last post until next week, when apparently we can expect a snowy welcome. Hmmmm. Plenty of new material for kind followers – both of you..

20130321-075611.jpg

DELPHI DAWN