OCTOPUS’S GARDEN (TAKE 9) IN THE BAHAMAS


Octopus (Melinda Riger - Grand Bahama Scuba)

OCTOPUS’S GARDEN (TAKE 9) IN THE BAHAMAS

We are back again under the sea, warm below the storm, with an eight-limbed companion in its little hideaway beneath the waves.

Octopus (Melinda Riger - Grand Bahama Scuba)

It’s impossible to imagine anyone failing to engage with these extraordinary, intelligent creatures as they move around the reef. Except for octopodophobes, I suppose. I’ve written about octopuses quite a lot, yet each time I get to look at a new batch of images, I feel strangely elated that such a intricate, complex animal can exist. 

Octopus (Melinda Riger - Grand Bahama Scuba)

While examining the photo above, I took a closer look bottom left at the small dark shape. Yes my friends, it is (as you feared) a squished-looking seahorse, 

Octopus (Melinda Riger - Grand Bahama Scuba)

The kind of image a Scottish bagpiper should avoid seeingOctopus (Melinda Riger - Grand Bahama Scuba)

OPTIONAL MUSICAL DIGRESSION

With octopus posts I sometimes (rather cornily, I know) feature the Beatles’ great tribute to the species, as voiced with a delicacy and tunefulness that only Ringo was capable of. There’s some fun to be had from the multi-bonus-track retreads currently so popular. These ‘extra features’ include alternative mixes, live versions and – most egregious of all except for the most committed – ‘Takes’. These are the musical equivalent of a Picasso drawing that he botched or spilt his wine over and chucked in the bin, from which his agent faithfully rescued it (it’s now in MOMA…)

You might enjoy OG Take 9, though, for the chit chat and Ringo’s endearingly off-key moments.

All fabulous photos by Melinda Riger, Grand Bahama Scuba taken a few days ago

Octopus (Melinda Riger - Grand Bahama Scuba)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS


Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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. 

Diagram of adult solitary tunicate

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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. 

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

PEACOCK FLOUNDERS: NOW YOU SEE THEM…


Peacock Flounder (Melinda Riger / G B Scuba)

        PEACOCK FLOUNDERS

MASTERS OF SUBAQUATIC CAMOUFLAGE

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.

Peacock Flounder (Melinda Riger / G B Scuba)

ROVING EYES

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.

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 ‘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.

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 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. 

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 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

Peacock Flounder (Melinda Riger / G B Scuba)

SEAHORSES: PREHENSILE TALES FROM THE REEF


Seahorse (Adam Rees / Scuba Works)

SEAHORSES: PREHENSILE TALES FROM THE REEF

It’s a while since I showcased these astonishing little creatures. Adam Rees of SCUBA WORKS is a diver who combines great underwater experience with wonderful photographic skills. Here is a showcase for some of Adam’s seahorse photography and the amazing detail he captures. If these images don’t make you want to get your head underwater and explore the reefs, I can’t think what will…

Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)

RANGE MAP by NAT GEO

Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)

shlifecycle-e1313548153493

Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)
Seahorse (Adam Rees / Scuba Works)

Seahorse by Alex Konahin

All fantastic photos: Adam Rees / Scuba Works; Range Map, Nat Geo; Lifecycle diagram, Seahorserun; Seahorse GIF, Alex Konahin

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS


Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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. 

Diagram of adult solitary tunicate

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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. 

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

OCTOPUS’S GARDEN (TAKE 9) IN THE BAHAMAS


Octopus (Melinda Riger - Grand Bahama Scuba)

OCTOPUS’S GARDEN (TAKE 9) IN THE BAHAMAS

We are back again under the sea, warm below the storm, with an eight-limbed companion in its little hideaway beneath the waves.

Octopus (Melinda Riger - Grand Bahama Scuba)

It’s impossible to imagine anyone failing to engage with these extraordinary, intelligent creatures as they move around the reef. Except for octopodophobes, I suppose. I’ve written about octopuses quite a lot, yet each time I get to look at a new batch of images, I feel strangely elated that such a intricate, complex animal can exist. 

Octopus (Melinda Riger - Grand Bahama Scuba)

While examining the photo above, I took a closer look bottom left at the small dark shape. Yes my friends, it is (as you feared) a squished-looking seahorse, 

Octopus (Melinda Riger - Grand Bahama Scuba)

The kind of image a Scottish bagpiper should avoid seeingOctopus (Melinda Riger - Grand Bahama Scuba)

OPTIONAL MUSICAL DIGRESSION

With octopus posts I sometimes (rather cornily, I know) feature the Beatles’ great tribute to the species, as voiced with a delicacy that only Ringo was capable of. There’s some fun to be had from the multi-bonus-track retreads currently so popular. These ‘extra features’ include alternative mixes, live versions and – most egregious of all except for the most committed – ‘Takes’. These are the musical equivalent of a Picasso drawing that he botched or spilt his wine over and chucked in the bin, from which his agent faithfully rescued it (it’s now in MOMA…)

You might enjoy OG Take 9, though, for the chit chat and Ringo’s endearingly off-key moments.

All fabulous photos by Melinda Riger, Grand Bahama Scuba taken a few days ago

Octopus (Melinda Riger - Grand Bahama Scuba)

YELLOWTAIL PARROTFISH: BAHAMAS REEF FISH (54)


Yellowtail (Redfin) Parrotfish (Melinda Rogers / Dive Abaco)

YELLOWTAIL (REDFIN) PARROTFISH: BAHAMAS REEF FISH (54)

The yellowtail parrotfish (sometimes known as a redfin) is one of around half-a-dozen kinds of parrotfish found among the coral reefs of the Bahamas, and sometimes in seagrass areas. There are many other related species worldwide (about 80). Parrotfish are among the most important fishes on the reef because they play a major role in BIOEROSION , a vital process for the health of the reef.

Yellowtail (Redfin) Parrotfish (Melinda Rogers / Dive Abaco)

A. FEEDING & BEACH BUILDING

  • Their dental arrangements – a mouthful of meshing teeth – form the characteristic ‘beak’
  • Primarily herbivores but also snack on small creatures, organisms, or even molluscs
  • As they feed on their favourite algae, their teeth grind up the coral which they ingest
  • They digest the coral & excrete it as sand, becoming a component of your favourite beach
  • The teeth grow continuously, replacing ones worn away by grinding coral as they graze
  • They are a vital species in preventing algae from choking coral: essential reef cleaners

Yellowtail (Redfin) Parrotfish (Melinda Rogers / Dive Abaco)

B. PARROTFISH: PERSONAL INFORMATION

  • Some secrete a protective mucous cocoon to sleep in or as concealment from predators
  • Mucous also helps to heal damage, repel parasites, & protect them from UV light
  • As they develop from the juvenile stage, most species change colour significantly
  • In some species, juveniles change colour temporarily for protective purposes
  • These are “sequential hermaphrodites”, turning from female to male (‘protogyny’)
  • Single males tend to have several lady friends, and aggressively defend their love rights
  • Parrotfish are PELAGIC SPAWNERS. Females release many tiny buoyant eggs into the water
  • The eggs float freely then eventually sink to the coral until they hatch
  • Unlike almost all other fishes, they use their pectoral fins to propel themselves
  • Feeding behaviour / dietary requirements make them (thankfully) unsuitable for aquariums (or aquaria, if you prefer)

Yellowtail (Redfin) Parrotfish (Melinda Rogers / Dive Abaco)

WHAT WAS THAT ABOUT CHANGING SEX?

  • Parrotfish may undergo sex reversal in which developing female fish become males
  • Parrotfish born male remain male throughout their lives (“primary males”)
  • Female-born fish may change sex & colour to become male (“secondary males”)
  • Secondary males are fertile and generally mate with a single female
  • Females that stay female live in harems protected by a dominant “supermale” BUT…
  • …if the supermale dies, the largest female in the group changes sex to become male…
  • …AND amazingly adopts the coloration of the supermale (best ‘astounding fact’ of all)

Yellowtail (Redfin) Parrotfish (Melinda Rogers / Dive Abaco)

ARE PARROTFISH EDIBLE? JUST ASKING…

  • Parrotfish skin is very tough but their flesh is soft and degenerates quickly
  • Some species (eg blue parrotfish) carry ciguatera toxins – to be avoided
  • They are not considered a fishing target in Bahamas, nor a food-fish
  • Parrotfish are eaten elsewhere in the world however, for example Jamaica (cooked)
  • In Hawaii they are eaten raw – at one time they were reserved for royalty

VIDEO LINK: PARROTFISH POOP

Credits: Melinda Rogers / Dive Abaco for her great illustrative images. All photographs were taken on the reefs of Abaco, before the devastation and destruction of Hurricane Dorian last September; Florida Museum to cross-check facts; VIDEO – Scientific American

Yellowtail (Redfin) Parrotfish (Melinda Rogers / Dive Abaco)

AN OCTOPUS’S GARDEN, BAHAMAS


Octopus on coral reef, Bahamas (Melinda Riger / GB Scuba)

AN OCTOPUS’S GARDEN, BAHAMAS

Many of us, from time to time, might like to be under the sea, warm below the storm, swimming about the coral that lies beneath the ocean waves. Though possibly not resting their heads on the seabed. This undeniably idyllic experience would be perfected by the presence of an octopus and the notional garden he lives in. Enough to make any person shout and swim about – and quite excessively at that.

Octopus on the coral reef, Bahamas (Melinda Riger / GB Scuba)

The extra ingredient here is that these photographs were taken on the reef off the southern coast of Grand Bahama last week, less than 2 months after the island (along with Abaco) was smashed up by Hurricane Dorian. Thankfully, Grand Bahama Scuba has been able to return to relative normality and run diving trips again. Moreover, fears for the reefs have proved relatively unfounded. These images suggest little damage from the massive storm. The Abaco reefs have not yet been able to be assessed in any detail.

Octopus on the coral reef, Bahamas (Melinda Riger / GB Scuba)

The feature creature here was observed and photographed as it took it a octopodic wander round the reef. The vivid small fishes are out and about. The reef and its static (technically ‘sessile’) life forms –  corals, anemones and sponges –  look in good order. The octopus takes a pause to assess its surroundings before moving on to another part of the reef.

Octopus on the coral reef, Bahamas (Melinda Riger / GB Scuba)

THE PLURAL(S) OF OCTOPUS REVISITED

A long time ago I wrote a quasi-learned disquisition on the correct plural for the octopus. There were at least 3 possibilities derived from Greek and Latin, all arguable but none so sensible or normal-sounding as ‘octopuses‘. The other 2 are octopi and octopodes. If you want the bother with the details check out THE PLURAL OF OCTOPUS

There’s an aspect I missed then, through rank ignorance I’d say: I didn’t check the details of the Scientific Classification. Now that I am more ‘Linnaeus-woke’, I have two further plural candidates with impeccable credentials. Octopuses are cephalpods (‘headfeet’) of the Order Octopoda and the Family Octopodidae. These names have existed since naturalist GEORGES CUVIER (he of the beaked whale found in Bahamas waters) classified them thus in 1797.  

RH ADVICE stick with ‘octopuses’ and (a) you won’t be wrong (b) you won’t get into an un-winnable argument with a pedant and (3) you won’t sound pretentious

Octopus on the coral reef, Bahamas (Melinda Riger / GB Scuba)

OPTIONAL MUSICAL DIGRESSION

Whether you are 9 or 90, you can never have too much of this one. If you are somewhere in the middle – or having Ringo Starr free-styling vocals doesn’t appeal – you can. Step back from the vid.

All fabulous photos by Melinda Riger, Grand Bahama Scuba, Nov 2019

Octopus on the coral reef, Bahamas (Melinda Riger / GB Scuba)

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)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS


Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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. 

Diagram of adult solitary tunicate

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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. 

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

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

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

HAWKSBILL TURTLES: ENJOY THEM WHILE YOU CAN


Hawksbill Turtle Bahamas (Melinda Riger / G B Scuba)

HAWKSBILL TURTLES: ENJOY THEM WHILE YOU CAN

Pliny the Elder (CE 23–79) was one of the earliest naturalists, besides being a philosopher, author and military commander. He wrote Naturalis Historia (Natural History), a wide-ranging work that became a model for later scholarly works, including forms of Encyclopedia. And, as he so nearly wrote, ‘si non amas testudines, vacua anima tua est’ (he that loves not sea turtles, has an empty mind)*

Hawksbill turtle grazing while a French angelfish looks onHawksbill Turtle with French Angelfish, Bahamas (Melinda Riger / G B Scuba)

There can be few better ways to start the New Year than with some gorgeous Hawksbill Turtles  Eretmochelys imbricata, plus a sprinkling of turtle facts to give 2019 a good push into orbit. Fortunately still available in Bahamas waters, the continued existence of Hawksbills is under serious threat. Make the most of your opportunities.

Hawksbill Turtle Bahamas (Adam Rees / Scuba Works)

  • Guesstimates of the world Hawksbill Turtle population suggest that there are 5 main groups in the oceans, with few enough individuals – especially breeding females – to warrant an IUCN listing of the species as critically endangered
  • I doubt that many will forget that the next IUCN category is… extinct (≠ ‘fun fact’)
  • The largest Hawksbill colony in the world nests on an island in Queensland Australia
  • Turtles leave the sea to lay eggs in a hole dug on the beach, before returning to the sea.
  • The eggs hatch after c60 days… the turtlings emerge and are then on their own
  • Hawksbills are omnivorous, mainly eating sponges (& immune from sponge toxins)
  • They also eat sea anemones, mollusks, and jellyfish
  • Their grazing lifestyle is an important component of a healthy coral reef ecosystem

Hawksbill Turtle Bahamas (Adam Rees / Scuba Works)

  • Though their shells are hard, Hawksbills are prey for sharks, crocodiles, octopuses and the biggest predator of all, humans“.
  • Despite international Hawkbill protection and conservation measures, they continue to be illegally hunted – including, in some places, for food.
  • Their lovely shells – tortoiseshell – are illegally traded for use for ornaments and jewellery
  • Japan makes its own rules (as with whales) for traditional & no doubt research purposes
  • ‘Tortoiseshell’ is the illegal item most frequently confiscated by custom officials
  • Reef and beach degradation, development, light pollution (confuses the baby turtles trying to paddle to the sea), ocean pollution / marine debris, and illegal practices are among the greatest dangers to the survival of the species. All are caused, directly or indirectly, by you and indeed me

Hawksbill T ©Melinda Riger + G B Scuba copy.jpg

Credits: wonderful photos by Melinda Riger / Grand Bahama Scuba (1, 2, 5) & Adam Rees / Scuba Works (3, 4, 6); Widecast; Nature Conservancy; OneKind Planet

Hawksbill Turtle Bahamas (Adam Rees / Scuba Works)

* Do not believe this – I invented it. The pretentious quote that props up the other stuff, that is – all the rest is true…

BAHAMAS REEF FISH (48): SCHOOLMASTER SNAPPER


Schoolmaster Snapper (Melinda Riger @ G B Scuba)

BAHAMAS REEF FISH (48): SCHOOLMASTER SNAPPER

November 1st already, and the first time I am prepared to consider the possibility of the onset of Christmas, with its attendant joys yet complications… Meanwhile, I thought I might have run out of types of reef fish to feature in this series long before I got to 50. Yet here we are, two short of that target, with a species of snapper I haven’t even mentioned before. I am (frankly) a rather feeble swimmer, and do not possess a viable underwater camera. So there’s no way I could show these denizens of the not-especially-deep without heavy reliance on others, in particular the outstanding photos of diver Melinda Riger of Grand Bahama Scuba; and the memorable ones from Adam Rees of Scuba Works that include some of the more obscure species that appear in my WTF? (What’s That Fish) series. 

Schoolmaster Snapper (Melinda Riger @ G B Scuba)

The schoolmaster snapper (Lutjanus apodus) lives among the coral reefs and mangroves of the Caribbean and further north to the northern Bahamas and Florida. Generally they are quite small, not much more than 12- 18 inches. They tend to hang out in ‘schools’, which several sources suggest as the reason they got their common name. But schoolmasters don’t really move around in large groups, do they? It’s school pupils that do that, but ‘Pupil Snapper’ wouldn’t cut it as a fish name I guess.

Schoolmaster Snapper (Melinda Riger @ G B Scuba)

10 SCHOOLMASTER SNAPPER FACTS TO PONDER

  • One pair of upper teeth are so large they protrude when the fish shuts its mouth
  • Their side scales are so arranged that diamond shapes are produced
  • There’s plenty to learn about their fin arrangements, but not necessarily to remember
  • Their jaws don’t open very wide, so their prey tends to be quite small
  • Unlike fish that change sex as they grow, these ones retain their birth gender for life
  • When they spawn they produce their gametes simultaneously, and swim away
  • The fertilised eggs sink to the bottom, where they have to take their chances
  • Though small, they are good to eat and are fished for recreation and commercially
  • Regionally there are specific regulations as to catch length & limits, hook type, bait etc
  • Like all snappers and many other fish species, these fish are associated with ciguatera

Schoolmaster Snapper (Melinda Riger @ G B Scuba)

RECIPES

For those who enjoy cooking (whatever that is), you probably know exactly how you like to cook your snappers. For anyone else, here’s a site that proposes several different ways to cook them, with helpful tips. These seem to apply to all snapper species, most of which are available free in the Bahamas. http://www.allfishingbuy.com/Fish-Recipes/Snapper-Recepies.htm

My favourite schoolmaster snapper photo of those featured hereSchoolmaster Snapper (Melinda Riger @ G B Scuba)

POSSIBLE MEDICAL BENEFITS FROM EATING SNAPPERS

These are alleged to include (except when fried): protection against certain types of stroke, reduction of heart arrhythmia, and defence against certain types of cancer. Don’t take my word for it, though. And definitely don’t rely on a snapper-based diet regime. I think the most that can safely be said is that eating snapper will do you no harm (except when fried) and may conceivably have a marginal benefit on health along with a balanced diet, exercise, minimal alcohol intake and all the routines that we strictly adhere to for a healthy life. In our dreams, anyway.

Schoolmaster Snapper (Albert Kok)

Credits: All great pics by Melinda Riger / GB Scuba except #6 Albert Kok; range map, Wiki. Magpie pickings.

Schoolmaster Snapper (Melinda Riger @ G B Scuba)

 

BAHAMAS SEA TURTLES: IN THEIR ELEMENT


Green Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba)

Green Turtle

BAHAMAS SEA TURTLES: IN THEIR ELEMENT

Of all the sea creatures in the limpid waters of the Bahamas, turtles are rightly among the most loved. These days, what with habitat degradation below the waves and the destruction of nesting sites on land, turtles have a hard time simply fighting for survival. And that’s before they have ingested the plastic garbage that mankind pours into their living quarters, by now probably beyond effective remedial action forever. So here are some gorgeous turtles to admire, while stocks last…

Hawksbill Turtles enjoying life around a still-healthy reefHawksbill Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba) Hawksbill Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba)

A hawksbill snacking on a spongeHawksbill Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba)

Interaction with other underwater species: gray angelfish and a rock beautyHawksbill Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba) Hawksbill Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba)

If you are concerned about the plight of turtles and indeed other denizens of the thickening plastic soup we still call ‘ocean’, you could investigate the work some of the organisations that tackle the problem in the Bahamas and beyond. To name but a few, our own FRIENDS OF THE ENVIRONMENT; the BAHAMAS NATIONAL TRUST; the Bahamas Reef Environmental, Educational Foundation BREEF; the CAPE ELEUTHERA FOUNDATION; and the SEA TURTLE CONSERVANCY

Photo credits: all great photos by Melinda Riger / Grand Bahama Scuba

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

SPERM WHALES – BMMRO FIELD TRIP, BAHAMAS


Sperm Whales, Bahamas (BMMRO)

SPERM WHALES – BMMRO FIELD TRIP, BAHAMAS

I can never quite get my head around the fact that the waters around Abaco are home to the twin leviathans, sperm whales and humpback whales. And before anyone points it out, I realise they can’t actually be twins: sperms whales (cachelots) are TOOTHED WHALES whereas humpback whales are BALEEN WHALES

Sperm Whales, Bahamas (BMMRO)

During November, the Bahamas Marine Mammal Research Organisation (BMMRO) undertook a rather special field trip. Using sophisticated devices, the scientists first located a group of sperm whales, and then tracked them through the night using the communications between the creatures – ‘vocalisations’ – to follow them. Later analysis of the recordings will have made it possible to identify the individuals through their unique vocal patterns – and so to recognise them again. 

Sperm Whale, Bahamas (BMMRO)

The hydrophonic equipment used is extremely sensitive, and can pick up the sounds made by whales and dolphins over a great distance. The box of tricks looks deceptively modest – I took these photos on a previous trip when we were looking for beaked whales and dolphins. Charlotte Dunn holds the microphone submerged on a cable and underwater sounds are amplified so that the slightest chirrup of a dolphin can be heard by everyone on the vessel. The sounds are recorded and locations carefully logged.

Besides the sperm whales, the BMMRO team also had sightings of spotted dolphins, bottlenose dolphins and beaked whales during the field trip. These bonus sightings will also have been logged for future reference. It all adds to the detailed research data that assists the conservation of the prolific marine mammal life in Bahamian waters.

Atlantic Spotted DolphinsAtlantic Spotted Dolphins, Bahamas (BMMRO)

By the time one of the whales decided to breach, it was some distance away, so I’m afraid I can’t bring you a dramatic close-up from the trip. But just to see this view at all is breathtaking.

All photos BMMRO except the 2 hydrophone ones on the research boat (Keith Salvesen)

ATLANTIC SPOTTED DOLPHINS OFF ROCKY POINT, ABACO


Atlantic Spotted Dolphins off Rocky Point, Abaco

This pair was in a group of 8 Atlantic Spotted Dolphins that we encountered yesterday during a day’s expedition on the Bahamas Marine Mammal Research Organisation (BMMRO) research boat. We spent nearly an hour with them, and there will be a longer post about these magnificent creatures in due course. But right now, I’m still in single image posting mode while “on-island”…

Photo: Keith Salvesen / BMMRO

SEAHORSES: PREHENSILE TALES FROM THE REEF


Seahorse (Adam Rees / Scuba Works)

SEAHORSES: PREHENSILE TALES FROM THE REEF

It’s a year since I last posted about these amazing little creatures, seahorses. I featured a number of photos by Melinda Riger, a couple of videos, some useful facts about them, and for some reason some useless facts that I came across in researching the post. You can chase it down here: SEAHORSES 1

Adam Rees of SCUBA WORKS is another diver, like Melinda, who combines great underwater experience with wonderful photographic skills. This posts showcases some of Adam’s seahorse photography, and if it doesn’t want to make you explore the reefs, I can’t think what will…

Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)

Seahorse Range MapMap: Seahorse range (Nat Geo)

Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)

shlifecycle-e1313548153493

Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)Seahorse (Adam Rees / Scuba Works)
Seahorse (Adam Rees / Scuba Works)

Seahorse by Alex Konahin

All phantastic photos: Adam Rees / Scuba Works; Range Map, Nat Geo; Lifecycle diagram, Seahorserun; Seahorse GIF, Alex Konahin

BLUE CHROMIS: BAHAMAS REEF FISH (29)


Blue Chromis & Coral ©Melinda Riger @ GB Scuba

BLUE CHROMIS: BAHAMAS REEF FISH (29)

The little blue chromis Chromis cyanea will be instantly familiar to any snorkeler or scuba diver on the coral reefs of the Bahamas. These ever-present small fish – 6 inches long at most – are remarkable for their iridescent deep blue colour that flashes as they dart in and out of the coral and anemones of the reef.

Blue Chromis ©Melinda Riger @ G B Scuba

Although at first sight  this chromis species – one of many – looks blue all over, adults have a black dorsal stripe and black edging to their fins. They make colourful additions to aquariums, though to my mind they look far more attractive nosing about the reefs foraging for the zooplankton upon which they feed (see header image for details…)

Blue Chromis ©Melinda Riger @ GB Scuba

The blue chromis was the second fish species I encountered on my first ever reef dive, at Fowl Cay Marine Preserve with Kay Politano. The first fish was the endearingly inquisitive sergeant major with its smart black and yellow stripes which came right up to my googles to eyeball me. I loved that, even though my pitiful swimming technique meant that I had plenty of other distractions, not least remembering to breathe. Air, that is, rather than water.

Blue Chromis ©Melinda Riger @ GB Scuba

Chromis_cyanea_(blue_chromis)_(San_Salvador_Island,_Bahamas)

SO JUST HOW BIG ARE THESE FISH, COMPARED, SAY, TO A BLUE TANG?

Blue Tang with blue chromis in its wakeBlue Tang with Blue Chromis © Melinda Riger @GB Scuba copy

All photos Melinda Riger of Grand Bahama Scube, except the penultimate by James St John, taken in San Salvador

 

A VISIT TO BIMINI’S MARINE ENVIRONMENT (1)


Loggerhead Hatchling Bimini BMPAC

Loggerhead Hatchling (Bimini’s Marine Protected Area Campaign)

A VISIT TO BIMINI’S MARINE ENVIRONMENT (1)

Abaco is fortunate already to have special conservation areas, both on land (e.g. the huge National Park) and at sea (e.g. Fowl Cay Marine Preserve). Other preserves are in active stages of development. Elsewhere in the Bahamas, where the natural life is equally wonderful, battles are being fought to protect pristine habitat from the encroachments of modern life such as unsuitable development (or development in unsuitable locations). For this first look at Bimini, I am most grateful to Bimini’s Marine Protected Area Campaign  for permission to use some of their wonderful photographic archive that illustrates the vital importance of the mangroves, reefs, sea grass and pristine sea to marine life large and small. It’s worth checking out the background and surrounding context of these images to see the sort of habitat the creatures depicted prefer. This post features some of the larger species.

HAMMERHEAD SHARKS

Hammerhead Shark, Bimini (Grant Johnson/ 60 Pound Bullet)Hammerhead Sharks 3 Bimini's Marine Protected Area Campaign Hammerhead Shark 2 Bimini's Marine Protected Area Campaign Hammerhead Shark 4 Bimini's Marine Protected Area Campaign

NURSE SHARK NURSERY IN THE MANGROVES

Nurse Sharks Bimini's Marine Protected Area Campaign Nurse Shark BMPAC

BOTTLENOSE DOLPHINS

Dolphin 2 Bimini's Marine Protected Area CampaignDolphin Bimini's Marine Protected Area Campaign

RAYS

A pregnant female southern stingray, seen from belowSouthern Stingray (pregnant) Bimini's Marine Protected Area CampaignRay, Bimini's Marine Protected Area Campaign Ray, Bimini's Marine Protected Area Campaign

HAWKSBILL TURTLES

Turtle in Mangroves Bimini's Marine Protected Area CampaignHawkshead Turtle 2 Bimini's Marine Protected Area Campaign

CREDITS: Bimini’s Marine Protected Area Campaign with many thanks for use permission of their material including images © Grant Jonson / 60 Pound Bullet Photography, and to all other photographers featured. Overall, cheers to Bimini, wildlife and conservation…

“ALIEN FROM THE DEEP”: ABACO’S SCALELESS BLACK DRAGONFISH


Scaleless Black Dragonfish - Header - BMMRO Abaco

“ALIEN FROM THE DEEP”: ABACO’S SCALELESS BLACK DRAGONFISH

Prepared to be terrified. Beneath the placid turquoise waters of Abaco lurks a ruthless and implacable killer of hideous mien, armed with vicious teeth  … Yes, as the music from Jaws begins to throb round your temples I bring you… THE SCALELESS BLACK DRAGONFISH, aka the Deep Sea Dragonfish or Viperfish (of which it is one type). Oh, and it’s about 8 inches/ 20 cms long.

The specimen shown here was found off Rocky Point, Abaco during a whale and dolphin research trip by the BMMRO. This is an area where typical low waters give way to the far deeper waters of an arm of the Great Bahama Canyon. It is an excellent place for whale watching, since one effect of the canyon is to provide plentiful food of the sort that cetaceans thrive on. The chances of you ever meeting a dragonfish are very slim indeed, since they live at depths up to 1500 metres. 

MAP to be added after posting, to avoid FB’s deranged random ‘feature photo’ selection The black star at the south end of Abaco  (in the yellowish box) is where Rocky Point and Sandy Point are to be found.

BAHAMAS SEA DEPTH MAP (NEAQ)

Here is an account by BMMRO intern Luanettee Colebrooke who was lucky enough to be on the research vessel when this strange, vicious-looking creature was found. I have edited the material for present purposes, but I recommend reading the whole article which can be found on the BMMRO website HERE. You will get an excellent overview of a day’s research under the hot sun, and plenty about the collection of whale poop (a topic I have previously dwelt on HERE (“Familiar Feces“).

Scaleless Black Dragonfish - BMMRO Abaco
CREATURE by Luanettee’ Colebrooke, BMMRO intern, summer 2014
The crossing of this organism was by complete accident. It was something that none of us would have imagined finding floating along the surface of the water. For Dr Claridge, Jurique (another BMMRO summer intern from Cat Island) and I as Bahamians, who knew this creature even existed in our majestic waters? Who knew our waters were even that deep to hide this specimen? (I think Dr Claridge knew)
Our morning began as per the usual routine for a boat day. There are several research sites that we venture to regularly: Rocky Point for the coastal Bottlenose Dolphins, and an area about 2 miles south of Rocky Point for our very elusive and wary Blainville’s beaked whales, and the deep blue (a massive drop into waters that are 1500 metres deep) to listen for Sperm Whales.It is not that I do not believe that we have deep waters. The Tongue of the Ocean runs through the northern part of our country. My thought comes more from, ‘our waters are that deep’? To a point where light does not hit the bottom and organisms have to rely mainly on bioluminescence? It is a similar thought process I had when I saw a sperm whale for the first time. They are not small creatures of the sea. It is both an awe and scary thought that there are creatures out there we, as Bahamians, do not know exist in our waters.
Scaleless Black Dragonfish - BMMRO AbacoScaleless Black Dragonfish - BMMRO Abaco
“Our final activity of the day was tracking a sperm whale acoustically using a hydrophone…” There follows a graphic account of the technicalities of sperm whale poop collection and co-intern Jack’s “Faecal Dispersion Technique”. Then this: Jack stood up, Pringle in mouth and pointed to a black leather looking strap off of the port bow. “What is it?” Moving closer to the port, Jurique and I had our own thoughts. “It looks like a boxing glove strap,” he suggested. “More like an expensive underwater watch,” I mentioned. Dr. Claridge said, “It looks like a squid tentacle.” Jack added in, “More like the strap from a fin to me.” Our heads were turning with no closer answer. Taking it upon himself as the official sample collector, Jack popped back into the water to collect it. There were no sample pots large enough for it, so he had to use a large Ziplock bag to pick it up.
Scaleless Black Dragonfish - BMMRO AbacoLetting out a surprised chorus when he got back on the boat, we wondered what the heck it was. It had a mouth and a weird white patch that at first, I thought was its eye. The ventral abdominal section seemed swollen as if it had expanded from the decreasing pressure rising from the sea. As we looked at it and took photos, we determined several characteristics of the deceased specimen without having to autopsy it. The first was that it had three rows of needle like teeth that turned inward. There was what we assumed to be an angler under its ‘chin’ that had a murky transparent color. Another deduction we came to was the white dots that ran along the body all the way to its tail could be bioluminescent in nature like an angler. The pectoral fins were small and thin like a tooth pick. The final detail we took note of was the silver patch underneath its eyes.It was a type of angler fish we hypothesized. And it somehow ended up on the surface. There were several questions we voiced to each other: if it is a deep angler fish, how did it end up here? Where did it come from? Was it stunned by the sperm whale’s echolocation and pulled upwards as it surfaced? Later that night as we went through our faecal samples, photo IDs and data entry, the search began for what exactly this organism was. Jack did some image trickery and overlapped the photos with an alien from Alien. Scaleless Black Dragonfish c/w Alien - BMMRO AbacoI personally thought it looked more like Venom from Spiderman. As he did that, I took it upon myself to begin the search by looking up the most prominent feature: the angler on the anterior ventral side of the fish. By using this characteristic, I was able to narrow the organism down to a Scaleless Black Dragonfish by using several online scientific key identification guides and forums. The species we are still unsure about. The mystery continues…Scaleless Black Dragonfish - BMMRO Abaco
This creature is one of a number of dragonfish species found worldwide. This one might to be one of the genus Melanostomias (says he, hesitantly…). Like many deep sea creatures, its customary depths are pitch black, or nearly so; and so it is equipped with its own light source (bioluminescence), including the item dangling down from its lower jaw, called a barbel. The fish’s glow and no doubt the gleam of the barbel swaying around in the water act as a lure to attract prey that swim up to investigate and then.. snap! Those teeth start to do their work.
Scaleless black dragonfish (Melanostomias biseriatus) (imagesource.com)
I’ll end with an amazing short (2:28) video posted in early 2014 by ‘Indoona’. The accompanying description is the most authoritative account of the species and its little ways that I have  come across, complete with useful links. I include it before the video, noting only that the creature featured is a Pacific one from off the coast of California, and therefore not identical to the Abaco one.
                                                                       scaleless-black-dragonfish-mini-jpg          scaleless-black-dragonfish-mini-jpg          scaleless-black-dragonfish-mini-jpg

THE DEEP SEA DRAGONFISH OR VIPER FISH is an awesome looking creature from the middle depths of the ocean (this one comes from 600 metres or about 1000 feet deep). Also called the scaleless dragonfish, they are ferocious predators, with extremely large teeth compared to their body size. And they have one of nature’s most amazing tricks to give them the edge over their prey (more below).

There are several different species of dragonfish (one estimate is 67 species – all from the fish family known as Family Stomidae) and they are quite difficult to tell apart but this one is from the pacific depths of California and is likely Tactostoma macropus, the longfin dragonfish. Idiacanthus antrostomus is an Atlantic species that looks very similar – at least I think that’s the case correct me if I’m wrong.

They hunt with a bioluminescent barbel or lure. It is not glowing here but under the different lighting regimes I used – some of the darker images – you can see how much the lure stands out.

Sadly fish like this do not survive long on the surface, mainly because of temperature differences and mechanical damage in the net rather than pressure problems I think. It was caught in a cod-end trawl and filmed in a special tank (a kreisal aquarium). But is great to be able to share another wonder of the oceans on YouTube.

And their amazing trick? Unlike most other deep sea creatures which are sensitive to blue light – the dragonfish also produces a red light beam (see the organ to the rear of the eye) – it is also very sensitive to red light. Although red light does not travel very far underwater it allows them to see when other animals cannot and to sneak up on their prey – especially shrimps that glow in the red light. For more detail see: http://www.science-frontiers.com/sf10… and the work of Ron Douglas and Julian Partridge,http://blog.wellcomecollection.org/ta… (these images were filmed with the help of Julian and Ron). Oh and this dragon is not big – about 20 cm or just under a foot!

[youtube https://www.youtube.com/watch?v=i6cIoj7c2FI]

Credits: Luanettee Colebrooke, ‘Jack’ & BMMRO (to whom thanks as ever), imagesource.com, Indoona , and 2 sites I came across during my investigations – seasky.org & strangesounds.org

If you can’t get enough of dragonfish, check out this Tumblr site for dozens of images including photos, drawings, cartoons, and enough strange dragonfish-based characters to weird you out utterly… HERE