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

RED REEF RESIDENTS: A RUFOUS ROUND-UP IN THE BAHAMAS


Squirrelfish (Elvis) ©Melinda Riger @ Grand Bahama Scuba copy

Elvis the Squirrelfish

RED REEF RESIDENTS: A RUFOUS ROUND-UP IN THE BAHAMAS

It’s sunny and very hot. Time to take another dive with Melinda to see what is going on under water around the reefs. Here are some residents, a somewhat loose description since some of the denizens featured are not especially active. But they are alive, so they qualify by my wide rules. And please may we not get into a discussion about where precisely red and orange overlap. It’s a grey area. And it’s too hot to argue about it… Let’s start with three types of GROUPER that may be spotted in the northern Bahamas. In fact, they are always spotted. One of my favourite pictures is the Graysby – it’s such a great expression, and he really rocks the spots!

GRAYSBY
Graysby © Melinda Riger @ Grand Bahama Scuba copy

TIGER GROUPER AT A CLEANING STATION with Peterson Cleaning Shrimps & a GobyGrouper, Tiger with cleaning shrimps and goby ©Melinda Riger @ G B Scuba copyRED HINDRed Hind Grouper Melinda Riger @ G B Scuba copy

BLACKBAR SOLDIERFISHBlackbar Soldierfish ©Melinda Riger @ G B Scuba copy

HOGFISHHogfish ©Melinda Riger @ GB Scuba copy 2

SQUIRRELFISHSquirrelfish 2 copy

But red fish are not the only red reef residents. Here are some  that won’t swim away from you as you swim towards them to admire them…

A FEATHER DUSTER ON A SPONGEFeather Duster in a Sponge ©Melinda Riger @ Grand Bahama Scuba copy

RED SPONGERed Sponge ©Melinda Riger @ GB Scuba copyUNDERWATER GARDEN GROWING IN A RED CONTAINERCoral ©Melinda Riger @ G B Scuba 2 copy

ANOTHER VARIED REEF GARDENReef Garden ©Melinda Riger@ G B Scuba copy

CORALS WITH (I have just noticed) A LURKING LIONFISH Coral ©Melinda Riger @ G B Scuba 1 copy

CHRISTMAS TREE WORMS (see more of these amazing creatures HERE)Christmas Tree Worms ©Melinda Riger @ G B Scuba copy

All photos: Melinda Riger @ Grand Bahama Scuba

STICKING THEIR NECKS OUT: BAHAMAS REEF FISH (11)


Spinyhead Blenny

STICKING THEIR NECKS OUT: BAHAMAS REEF FISH (11)

The coral reefs of the Bahamas provide a home for a myriad of subaquatic creatures and plants. Not necessarily a safe one, though. Some species prefer to remain largely hidden to reduce the chances of becoming part of the lengthy reef food chain. Rocks, of course, can offer some security, but also the sandy bottom. Even brain coral can provide some protection…

JAWFISHJawfish ©Melinda Riger @GBS

This Yellowhead Jawfish has its eggs safely stored in its mouthYellowhead Jawfish with eggs in mouth ©Melinda Riger GB Scuba

SAND DIVER FISHSand Diver Fish Sand Diver ©Melinda Riger @ G B Scuba

ROUGHHEAD BLENNY IN BRAIN CORAL (and header)Roughhead Blenny ©Melinda Riger @ G B Scuba Blenny ©Melinda Riger @GBS

…and in a different homeRoughhead Blenny © Melinda Riger @ G B Scuba

MANTIS SHRIMPMantis Shrimp ©Melinda Riger @GBSMantis Shrimp 2 ©Melinda Riger @GBS

…AND A VERY GOOD AFTERNOON TO YOU TOO, MR SPOTTED MORAY EELSpotted Moray Eel ©Melinda Riger @ G B ScubaAll Images: thanks to Melinda Riger of Grand Bahama Scuba

THE CORALS OF FOWL CAY MARINE PRESERVE, ABACO [VIDEO]


DCB GBG Cover Logo dolphin

THE CORALS OF FOWL CAY MARINE PRESERVE, ABACO

coral6

I usually have 3 or 4 planned posts on the go. Some are quick to compose, some are not. Especially those requiring technical input from the technically unsound – downloading a video, changing the file format, editing and polishing, uploading to a compatible ‘carrier’ etc. I’ve been meaning to get round to making some fish and reef videos from footage of a trip with Kay Politano of Abaco Above & Below. Now I have…coral8

If you are tolerant enough to at least start this one, which focusses on coral, can I restate the excuses? I swim like a panicking cat. I hadn’t snorkelled for a great many decades years until 2011. I was a stranger to underwater scenery, let alone photography. I wave my tiny camera around too excitedly, though not deliberately to inflict seasickness on hapless viewers… It is a bit less bad this time round, however. Luckily I can tell from my stats if anyone has bothered to click on the video below, and you can rely on me to trash the thing if I find a paltry (or non-existent) response. Best just to watch on the small screen, though.coral14

With those dire warnings, here is the video. I would be very interested to ID all the corals that can be seen. There are the easy ones like sea fan, elkhorn, mustard hill, brain… but what’s that one over there? No, behind the waving one…? Comments / suggestions welcome. And if you don’t much care for coral, there are some pretty fish to look at…

Music Credit: Adrian Legg’s ‘Old Friends’, from ‘Guitar Bones’

ADDENDUM JAN 13 I am really grateful to Capt Rick Guest for taking the time to view the video, and the trouble to analyse the contents. He has very helpfully highlighted many points of interest in the film, both as to coral and as to fish, so I’ll post his commentary in full, with my thanks. Of both interest and concern are Rick’s remarks about the Elkhorn Coral. I had wondered about its bleached look. It’s dying…

CORALS ETC

  • At 0:36 a lavender Sea Fan…(Gorgonia ventalina).
  • At 0:52 Yellow “Leaf”,or “Letuce Coral”. Agaricia species growing around a living soft coral called a “Sea Rod”. Soft Corals have living polyps which feed on plankton just like the hard corals.
  • At 1:02 More Agaricia, and a small Brain Coral at bottom. Either a Diploria, or Colpophylia species.
  • At 1:10 A Sergent Major fish, (Abedefduf saxatilus). One of my favorite Taxanomic names! Behind is mostly dead, Elkhorn Coral. The white areas being indicative of “White Plague”. A disease responsible for Coral Whiting…..Death!
  • At 1:37 A Blue Tang swims over some “Mustard Coral”… Porites porites.
  • At 1:55 A chubby “Chub” swims by. Likes caves and caverns and edible, but not palatable.  
  • At 2:33-38  Much coral bleaching damage here on these Elkhorn Corals.  
  • At 2:40-48 A Thalassoma bifaciatum,or “Blue Headed Wrasse” is swimmin’ about. This guy used to be a lady,but he’s a product of Protandric Hermaphrodism! When there’s a paucity of males in the area, a yellow female will step up and become a male for the school.
  • At 3:29 Lower right: a fine example of Millepora complanata,”Fire Coral”. Fire Coral is more related to Man-O-War, and jellyfish than Corals.
  • At 3:50 More Elkhorn Coral with White Plague  
  • At 4:23 Brain Coral, probably Diploria clivosa 

BEACHCOMBING AT THE DELPHI CLUB, ABACO – CORAL & NERITES


CONTRASTING CORAL SKELETONS

These two different types of coral skeleton are from the northern end (and just beyond) of the Delphi beach. The red marking on the second coral is some kind of natural accretion, I think – I have temporarily lost the exact details somewhere on my hard drive, but doubtless they will turn up sooner or later… You will find these red patches on shells as well as coral

COMMON ROSE CORAL

ANY IDEAS  – OR IS THIS WORM-RELATED?

Another dramatic coral you may come across – not least because there are usually one or two in the beach-harvested collection on the steps down to the beach – is Brain Coral (Diploria). Here is an example (Photo credit J. Stuby)

NERITES (Nerita)

Nerites are small sea-snails (gastropod molluscs) found in tropical waters around the world. Precise ID of the many types is confused by the different names used for many of them, both taxonomic and local. The majority of the black and white nerites in the pile below, all collected from the Delphi beach, are Checkered Nerites (Nerita Tessellata). In the heap there are a few larger whiter shells with red markings, which are the Four-Toothed Nerite (Nerita Versicolor).

Here are some of the above shells showing their varying patterns and sizes, seen with a few grains of sand for comparison. The 3 larger whiter ones with the flecks of red on them are the Four-Toothed Nerites.

Here are 3 example shells in close-up, together with a tiny, perfect Dwarf Atlantic Planaxis (Hinea lineata) at the end (previously misidentified as a Littorine). I didn’t notice it until I was sorting through the shells – in fact you can just see it towards the bottom right of the previous photo, above the small nerite that’s on its back. It may even have fallen out of a nerite, as did many of the sand grains.

These four upturned nerites show the dentate entrance, common (to a greater or lesser extent) to most nerites – maybe all. The top row are Four-toothed Nerites; the bottom row are Checkered Nerites. Another Nerite type found in the Bahamas is the Bleeding-tooth nerite (Nerita Peloronta). These are similar to the top ones, but have vivid orangey-red markings on the ‘teeth’ – hence their name.

Nerites, sand grains and the Planaxis: size comparison

A close up of the Planaxis, showing how amazingly detailed the pattern of such a tiny shell can be

All this may sound a bit learned and somewhat solemn. Dull even. In fact I had absolutely no idea about any of the above details until I got these shells out of their glass jar last week to photograph (apologies for using a chopping board) and did some digging… So if any shellologists or neritophiles read this and have corrections to suggest, be my guest… Use the comment box or the email address on the CONTACT page. ADDENDUM: many thanks to Colin Redfern for confirming the small nerites as Checkered, as opposed to Zebra; and the ‘littorine’ as a Dwarf Atlantic Planaxis Hinea lineata