TURTLE BREEDING SEASON & A SMALL POEM TO PONDER


Sea Turtle - Adam Rees / Scuba Works

TURTLE BREEDING SEASON & A SMALL POEM TO PONDER

The turtle lives ‘twixt plated decks
Which practically conceal its sex.
I think it clever of the turtle 
In such a fix, to be so fertile.

Sea Turtle - Adam Rees / Scuba Works

Anyone unfamiliar with the works of OGDEN NASH (1902 – 1971) would do well the check out his inimitable poetry, in which he takes extreme liberties with both rhyme and scansion to great comic effect. The poem above is a good example of Nash’s neat way with words. It always makes me laugh, anyway. So simple, looks so easy, but a very difficult trick to pull off consistently as Nash effortlessly does.Sea Turtle - Adam Rees / Scuba Works

As the turtle breeding season moves forward, I though this would be a good time to show a few of the great turtle photos taken by Adam Rees of ‘Scuba Works’.Sea Turtle - Adam Rees / Scuba Works

Sea Turtle - Adam Rees / Scuba Works

All photos: Adam Rees / Scuba WorksSea Turtle - Adam Rees / Scuba Works

BLUE TANG AS REEF FILM STAR


Blue Tang, Bahamas (Melinda Riger / Grand Bahama Scuba)

BLUE TANG AS REEF FILM STAR

Last summer, the big motion picture sensation for the bird world was, of course, Pixar’s ineffably adorable creation, Piper – the ultimate ‘Chick Flick’. This little ball of cartoon fluff was not, as some thought, based on a piping plover but on a sanderling – a type of sandpiper (clue in name). This 6 minute ‘short’ preceded the main event, the hugely popular Finding Dory. You can read all about the film Piper and the birding aspects of the film HERE

Blue Tang, Bahamas (Melinda Riger / Grand Bahama Scuba)

Finding Dory is not about a fish of the dory species, of course. Voiced by Ellen DeGeneres, Dory is in fact a species of surgeonfish Paracanthurus, the familiar blue tang found on the reefs of the Bahamas. To see these fish in Abaco waters, Fowl Cays National Park is always a good bet.

Blue Tang, Bahamas (Melinda Riger / Grand Bahama Scuba)

Dory can be identified as a maturing juvenile: blue, with a yellow tail. In due course – in time for the sequel film – she will become blue all over, with perhaps the odd flash of yellow (see photos above).

In real life, a baby blue tang is in fact entirely yellow, except for blue rings around the eyes. In Pixarland, however, Dory is just an adorbs miniature version of her youthful self.

Blue Tang juvenile, Bahamas (Melinda Riger / Grand Bahama Scuba)

Blue Tang are lovely to watch as they cruise round the reefs, sometimes in large groups. Their colouring ranges from pale to dark blue. However, these are fish that are best looked at and not touched – their caudal spines are very sharp. When the fish feels in threatened, the spine is raised and can cause deep cuts, with a risk of infection.  

Still from a crummy video taken at Fowl Cays some years back to illustrate a group of blue tangBlue Tangs, Fowl Cays Nature Park, Abaco Bahamas (KS)

Blue tangs are inedible, they apparently smell unpleasant, and they can cause ciguatera. However they are popular in the aquarium trade. This is a distinct downside of highly successful films such as Finding Nemo and Finding Dory. In defiance of the well-meant and broadly ecological message of both films, the trade in clown fish and to a lesser extent blue tang was boosted by their on-screen portrayal as adorbs creatures desirable for the entertainment of mankind… ‘Nuff said.

Blue Tang, Bahamas (Melinda Riger / Grand Bahama Scuba)

Credits: All excellent photos by Melinda Riger / Grand Bahama Scuba; one pathetically bad still from a low res video, me; cartoons purloined from an online aquarium somewhere or other

ABSORBING SPONGES ON THE BAHAMAS REEFS…


sponge-melinda-riger-gb-scuba

ABSORBING SPONGES ON THE BAHAMAS REEFS…

A while back I showed a collection of colourful sponges – one that you might come across with minimum equipment. Snorkel, mask, flippers. Oh, and a coral reef, if you happen to have one handy. I suspect that to quite a few people the word ‘sponge’ means soggy yellow thing, as found in the proximity of a bath. Or a scratchy nylon-based equivalent. Well, here are a few more sponges to enjoy. Some I can give you the names of, some I don’t know and am too idle busy to look up… Sorry.

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Candelabra Songe (with brittle stars attached)candelabra-sponge-melinda-riger-g-b-scubasponge-melinda-riger-g-b-scuba

Black Ball Spongesblack-ball-sponge-melinda-riger-g-b-scuba-copy

One for Valentine’s Dayheart-shaped-sponge-melinda-riger-gb-scuba

Vase Spongesvase-sponge- pink-melinda-riger-gb-scubavase-sponge-melinda-riger-g-b-scuba

sponges-and-coral-on-the-reef

Spawning Brown Encrusting Spongebrown-encrusting-sponge-spawning-melinda-riger-g-b-scuba

All photos: Melinda Riger, Grand Bahama Scuba

CHRISTMAS TREE WORMS: FABULOUSLY FESTIVE


christmas-tree-worms-adam-rees-scuba-works-copy

CHRISTMAS TREE WORMS: FABULOUSLY FESTIVE

music-notes-clip-art-png-music“Deck the Reefs with Worms Like Christmas Trees… Fal-La-La-etc-etc ” is a traditional Carol familiar to all. Well, most. Ok, some, then. Oh right – maybe with different words. Anyway, now is as good time as any to take a look at these remarkable plants creatures and subsurface symbols of good cheer.

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

10 CHRISTMAS TREE WORM FACTS TO PONDER

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

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

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

spirobranchus_giganteus_orange_christmas_tree_worm-nick-hobgood-wiki

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

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

christmas_tree_worm-nick-hobgood-wiki

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

I won’t lie. I found it hard to work out how the CTWs function in practice. There are plenty of resources showing them in their full glory, but that only takes one so far. Then I came across a short video that shows it all brilliantly simply (except for the reproduction part). So maybe I should have just posted this first and saved you (and me) some trouble…

The worm, invisible in its coral burrow, hoists its pair of trees. You can easily see small particles – possibly zooplankton – drifting in the water, and the radioles swaying to catch potential food. Bingo. It all makes sense! Next: the New Year Worm

Credits: Melinda Riger (G B Scuba); Adam Rees (Scuba Works); Nick Hobgood; Betty Wills; Absolutely Wild Visuals; MarineBio; Wikibits & Magpie Pickings

blue_christmas_tree_worm-betty-wills-wiki

SILVERSIDES: BAHAMAS REEF FISH (32)


silversides-school-melinda-riger-g-b-scuba

SILVERSIDES: BAHAMAS REEF FISH (32)

I have no idea if there is a collective noun for a large group of silversides. ‘Frenzy’ would cover it, but that is reminiscent of ‘feeding freezing’ which has a specialist meaning – and anyway, silversides are crazy even when they aren’t feeding. 24/7/12/365 as far as I can make out. I think ‘a panic of silversides’ might be the answer. They are just… all over the place at high speed. Sometimes swirling around pointlessly, other times moving in unison and suddenly all changing direction simultaneously, like a single creature made of tiny shards of silver.

silversides-school-melinda-riger-g-b-scuba-copyfish-frenzy-melinda-riger-gbs

There are quite a few silverside species around the world. The ones in the Bahamas are Atlantic silversides (Menidia menidia), also known in the north east of the United States as ‘spearing’. They seem to exist for two purposes. The main one is to be breakfast, lunch or dinner for larger fish, sea birds and shore birds. The other is for their usefulness in scientific research because of their sensitivity to environmental changes. 

silversides-melinda-riger-g-b-scuba-copy-2silversides-school-melinda-riger-gb-scuba

In one sense they are easy prey for predators. A determined fish will always manage a snack by swimming into the middle of a panic and (probably) simply by opening its mouth wide. On the other hand, their sheer numbers coupled with the speed and randomness of movement mean that a single may find a degree of safety in numbers. It’s hard for a predator to target any individual fish in the general melee and confusion. Silversides also favour seagrass beds, which give some shelter and protection – and a reasonably safe place to spawn. Or, as some of these photos show, they will hang around wrecks or squeeze into rocky spaces in the reef.

silversides-melinda-riger-g-b-scuba-copysilversides-melinda-riger-g-b-scuba

A panic of silversides apparently pouring like a waterfall down through a gap in the reefsilversides-waterfall-abaco-kay-politano

WHAT DOES A STATIONARY ATLANTIC SILVERSIDE LOOK LIKE?

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Some time ago we used to go to the reef at Fowl Cay Marine Preserve with Kay Politano, and I would snorkel with a small and very basic lo-res underwater camera. I was hampered by being a disgracefully feeble swimmer; by not having snorkelled for a length of time calculable in decades; and by being a complete novice at underwater photography.  Despite these not inconsiderable disadvantages I managed to cobble together a few short movies on my computer (I was new to that too). Here’s one that nearly works, in that it gives an idea of what happens if you ‘swim with silversides’. I know you scuba guys all swim with sharks, but cut me some slack here please…

Photo Credits: Main photos Melinda Riger of Grand Bahama Scuba; Silverside Waterfall by Kay Politano; motionless silversides by FISHBASE.ORGMusic: Goldon Giltrap, ‘Fast Approaching’

HOGFISH: BAHAMAS REEF FISH (31)


Hogfish at cleaning station ©Melinda Riger @GB Scuba

HOGFISH: BAHAMAS REEF FISH (31)

Hogfish. Fisherman’s delight… getting ‘high on the hog’. This wrasse species Lachnolaimus maximus is a reef denizen, especially where gorgonians are found. It has the distinction of being the only known member of its genus, and because it is IUCN listed as vulnerable, there are strict regulations governing bag, size, and gear limits to protect the species from overfishing.

Hogfish ©Melinda Riger @ G B Scuba

The hogfish gets its name from its long ‘pig-like’ snout, coupled with its rootling behaviour on the sea floor for crustacean prey.

Hogfish ©Melinda Riger @ GB Scuba copy ed Hogfish foraging ©Melinda Riger @ GB Scuba

GENDER STUDIES: IT’S COMPLICATED

The hogfish is a sequential hermaphrodite, meaning it changes sex during different life stages. Juvenile hogfish are female, but mature into males at around 3 years old.

Hogfish ©Melinda Riger @ G B ScubaHogfish ©Melinda Riger @ G B Scuba copy

Hogfish social groups are organized into harems, where one male will protect a group of females in his territory and mate with them.

Hogfish ©Melinda Riger @ GB Scuba Hogfish with isopods ©Melinda Riger @ GB Scuba

CAUTIONARY NOTE Capt. Rick, a loyal follower, has made another of his pertinent comments: “A bit of caution is necessary here! There is some history in the Bahamas of mild to severe Ciguatera poisoning from Hogs. Our M.O. was to only eat Hogs no larger than 5 or 6 lbs. Temporary or permanent blindness, paralysis, and even death is possible with bigger Hogs”. Ciguatera is also a problem with, for example, ‘cuda on Abaco. Those caught on the Marls (west) side are ok to eat; those from the east side have to be treated with circumspection…

Hogfish (with isopod above eye) ©Melinda Riger @ GB Scuba

Credits: all fantastic fish fotos – Melinda Riger at Grand Bahama Scuba

SPONGES ON THE REEF: A COLOURFUL MISCELLANY


Brown Tube Sponge ©Melinda Riger @ G B Scuba

SPONGES ON THE REEF: A COLOURFUL MISCELLANY

It’s time to take an up-close look at some of the sponges you may find as you snorkel or scuba round the reefs of the Bahamas. I am always amazed by how bright and colourful they are, and by their many different shapes and sizes. Even the unpromising sounding (slightly medical, even?) BROWN TUBE SPONGE turns out to be fascinating to examine closely. Here are some more sponge species. 

CANDELABRA SPONGECandelabra Sponge ©Melinda Riger @ G B Scuba copy

STOVE PIPE SPONGEStove Pipe Sponge ©Melinda Riger @ G B Scuba

PURPLE VASE SPONGEVase Sponge, purple ©Melinda Riger @ G B Scuba

BRANCHING TUBE SPONGE WITH ROPE SPONGESponges - Branching Tube Sponge with rope sponge ©Melinda Riger @ GB Scuba

PURPLE TUBE SPONGEPurple Tube Sponge ©Melinda Riger @ GB Scuba

PURPLE SPONGE WITH GIANT ANEMONEPurple Sponge : Giant Anemone ©Melinda Riger @ G B Scuba

VASE SPONGEVase Sponge ©Melinda Riger @ G B Scuba

The above sponges represent a fraction of the sponge varieties found on Bahamas reefs. I’ll post some more quite soon. All this has made me want to go for a snorkel. But right now I am 30 miles from the sea. And I have no gear…

HANG ON A MOMENT! WHAT IS A SPONGE WHEN IT’S AT HOME?

It’s really very simple: if you are ever asked the question, just reply “a sponge is a primitive sedentary aquatic invertebrate with a soft porous body that is typically supported by a framework of fibres or calcareous or glassy spicules. Sponges draw in a current of water to extract nutrients and oxygen”.

AND WHAT, PRAY, IS A SPICULE?

You’re having a laugh… if you seriously want to know, read the abbreviated version about them HERE. And admire this microscopic collage of ‘demospongiae spicule diversity’ made available by the wonders of Wiki and the research of about 20 credited scientists.

Demospongiae_spicule_diversity

All photos: Melinda Riger, Grand Bahama Scuba. Tip of the hat to Wiki and scientists