ELKHORN CORAL, ABACO BAHAMAS (DORIAN UPDATE)


Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

ELKHORN CORAL, ABACO BAHAMAS (DORIAN UPDATE)

Elkhorn coral (Acropora palmata) is a widespread reef coral, an unmistakeable species with large branches that resemble elk antlers. The dense growths create an ideal shady habitat for many reef creatures. These include reef fishes of all shapes and sizes, lobsters, shrimps and many more besides. Some of these are essential for the wellbeing of the reef and also its denizens.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

GOOD POST-DORIAN NEWS ABOUT ABACORAL

A recent report from FRIENDS OF THE ENVIRONMENT brings encouraging news about the reefs of  Abaco post-hurricane, and an indication of the resilience of the coral to extreme conditions (with one exception for a reef too close to the shore to avoid damage from debris).

Shortly before Dorian hit, The Perry Institute for Marine Science and its partners surveyed reefs across Grand Bahama and Abaco to assess their health. Following Dorian, they were able to reassess these areas and the impact of the hurricane. Over the 370 miles that the surveys covered, minimal damage was found on the majority of reefs. Unfortunately Mermaid Reef, where FRIENDS does most of our educational field trips, sustained extensive damage due to debris from its close proximity to the shoreline. We are looking into how we can help with logistics to get the debris removed, and hopefully the recovery will begin soon.

Elkhorn Coral, Pelican Cays, Abaco Bahamas (Friends of the Environment)

Elkhorn coral standing strong post-Dorian at Sandy Cay Reef, Pelican Shores, Abaco

The scientists were also able to visit four of the Reef Rescue Network’s coral nurseries and assess out-planted corals in national parks in both Grand Bahama and Abaco. The great news is that all of the corals on these nurseries survived the storm and will be used to support reef restoration. Also from the surveys, it appears that our offshore reefs around Abaco sustained minimal damage, including Sandy Cay Reef in Pelican Cays Land and Sea Park (pictured above). This gives us hope for the recovery of our oceans post-Dorian and proves how resilient these amazing ecosystems are.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

Examples of species vital for healthy corals include several types of PARROTFISH, the colourful and voracious herbivores that spend most of their time eating algae off the coral reefs using their beak-like teeth. This algal diet is digested, and the remains excreted as sand. Tread with care on your favourite beach; in part at least, it will consist of parrotfish poop.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

Other vital reef species living in the shelter of elkhorn and other corals are the CLEANERS, little fish and shrimps that cater for the wellbeing and grooming of large and even predatory fishes. Gobies, wrasse, Pedersen shrimps and many others pick dead skin and parasites from the ‘client’ fish including their gills, and even from between the teeth of predators. This service is an excellent example of MUTUALISM, a symbiotic relationship in which both parties benefit: close grooming in return for rich pickings of food.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

VULNERABILITY TO OFFICIALLY NON-EXISTENT CLIMATE CRISIS

Formally abundant, over just a couple of decades elkhorn coral has been massively affected by [climate change, human activity and habitat destruction] inexplicable natural attrition in many areas. One cause of decline that is incontrovertible is damage from storms, which are empirically increasing in both frequency and intensity, though apparently for no known reason.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

Physical damage to corals may seriously impact on reproductive success; elkhorn coral is no exception. The effects of a reduction of reef fertility are compounded by the fact that natural recovery is in any case inevitably a slow process. The worse the problem gets, the harder it becomes even to survive let alone recover. 

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

SO HOW DOES ELKHORN CORAL REPRODUCE?

There are two types of reproduction, which one might call asexual and sexual:

  1. Elkhorn coral reproduction occurs when a branch breaks off and attaches to the substrate, forming a the start of a new colony. This process is known as fragmentation and accounts for roughly half of coral spread. Considerable success is being achieved now with many coral species by in effect farming fragments and cloning colonies (see above, Reef Rescue Network’s coral nurseries)
  2. Sexual reproduction occurs once a year in August or September, when coral colonies release millions of gametes by broadcast spawning (there’s much more to be said on this interesting topic, and one day I will)

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

THE FEATURED PHOTOGRAPHS

You may have wondered in which healthily coral-infested waters these superb elkhorn coral photographs were taken. Did I perhaps source them from a National Geographic coral reef special edition? In fact, every image featured was obtained among the reefs of Abaco.

All except the recent Perry Institute / Friends of the Environment photo were taken by Melinda Rogers of Dive Abaco, Marsh Harbour. The long-established and highly regarded Dive Shop she and her husband Keith run was obliterated (see above) less than 3 months ago by Hurricane Dorian, along with most of the rest of the town. It’s a pleasure to be able to showcase these images taken in sunnier times.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

AN OCTOPUS’S GARDEN, BAHAMAS


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

AN OCTOPUS’S GARDEN, BAHAMAS

Most 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. An undeniably idyllic experience that is 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)

 

 

 

SOME NICE PICS OF BAHAMAS WILDLIFE… WHILE TECHIES LABOUR


Ring-billed Gull, Abaco Bahamas (Nina Henry)

SOME NICE PICS OF BAHAMAS WILDLIFE…

WHILE TECHIES LABOUR

Western Spindalis, Abaco Bahamas (Keith Salvesen)

I’m never quite sure how far it’s permissible to go beyond ‘really pissed off’ about a tech problem. Anything much stronger seems a bit indulgent both in itself and especially when measured against the far-reaching despair experienced by many in far more important areas of life.

Northern Parula Warbler, Abaco Bahamas (Bruce Hallett)

I am just having a huge “Grrrrrrrrr” moment because my complex blog menu, with 3 rows of headings and carefully curated nests of drop-downs under each, has been scrubbed by persons or AI unknown. It’s several years of cumulative and (mostly) pleasurable organisational work up the spout.

As a Brit, may I be permitted to say ‘bother’. Or maybe ‘Dash it all?’ Or declare that I’m a mite cheesed orf? To which a fair response would be “it’s just a trivial inconvenience, get over it…”

Abaco Parrot (Craig Nash)

For the moment, here are some nice pics to enjoy, all taken on Abaco. I’m happy to say that right now, 7 weeks since Dorian, there are promising signs that in some areas of Abaco, the birds are starting to show themselves – including a few winter warblers. See you the other side of rethinking my Menu…

Conch shell, Schooner Bay Abaco Bahamas (Keith Salvesen)Western Spindalis, Abaco Bahamas (Keith Salvesen)

Credits: Nina Henry, Bruce Hallett, Mary Kay Beach, Craig Nash, Keith Salvesen / Rolling Harbour, Charlotte Dunn / BMMRO (western spindalis badge, moi)

Humpback Whale tailing, Abaco Bahamas (Charlotte Dunn / BMMRO)

HIDDEN DEPTHS: LIFE ON ABACO’S CORAL REEFS


Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)

HIDDEN DEPTHS: LIFE ON ABACO’S CORAL REEFS

Nearly 4 weeks after the devastation of Hurricane Dorian, the island and its cays are beginning to emerge gradually from the wreckage and the desolation. The extent of the disaster on the ground is clear, not least from the aerial photos – first drone, then plane, and now Google – of ‘before’ and ‘after’. 

Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)

At the stage, it isn’t possible to determine the extent to which the underwater world has been affected. The storm surge was huge and the waves were savage. The progress of the storm was slow (and it went on to stall over equally damaged Grand Bahama). Who knows the effect on the corals and other reef life for which Abaco is renowned.

Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco) Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)

This pictorial post is a reminder of how things were below the surface of Abaco waters before Dorian struck. If it lifts spirits to any degree, I shall be glad.

Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco) Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)

All these photos are by Melinda Rodgers who, with Capt Keith, are DIVE ABACO. Many will know how badly they have fared, being in the heart of Marsh Harbour. We wish them a speedy return to the wonderful enterprise they have run for many years. I’m pleased to be able to show the beauty of the reefs in happier times from their archive.

Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)

Credits: Melinda Rodgers /  Dive Abaco

Reef Coral Abaco Bahamas (Melinda Rodgers / Dive Abaco)

URCHIN RESEARCHIN’: SEA HEDGEHOGS OF THE REEF


Long-spined sea urchin Diadema antillarum (Melinda Rodgers / Dive Abaco)

URCHIN RESEARCHIN’: SEA HEDGEHOGS OF THE REEF

The long-spined sea urchin Diadema antillarum featured in this post is one of those creatures that handily offers its USP in its name, so you know what you are dealing with. Something prickly, for a start. These are creatures of the reef, and many places in the Caribbean and in the western Atlantic generally sustain healthy populations.

Long-spined sea urchin Diadema antillarum (Melinda Rodgers / Dive Abaco)

These animals are essentially herbivores, and their value to vulnerable coral reefs cannot be overstated. Where there is a healthy population of these urchins, the reef will be kept clean from smothering algae by their methodical grazing. They also eat sea grass.

Long-spined sea urchin Diadema antillarum (Melinda Rodgers / Dive Abaco)

HOW DO THE SPINES OF DIFFERENT KINDS OF URCHIN COMPARE?

Small sea urchins species have spines a few cms long at most. The long-spine variety exceed 10 cms, and the largest may have spines up to 30 cms (= 1 foot) long. The length, as shown here, means that when the creatures are safely lodged in crevices near their algae supply, their spines remain very visible.
Long-spined sea urchin Diadema antillarum (Melinda Riger / G B Scuba)
Anatomy of a long-spined sea urchin. You may possess a few of these organs yourself…

Long-spined sea urchin Diadema antillarum anatomy diagram (wiki)

Long-spined sea urchin Diadema antillarum (Melinda Rodgers / Dive Abaco)

CAN YOU GIVE US A TEST, PLEASE?

As with SAND DOLLARS and similar creatures, the skeleton of a sea urchin is known as a ‘test’. Urchin tests are remarkably beautiful, especially seen in sunlight. Here are 2 examples I photographed a while ago. You’ll immediately notice the delicate colours and the amazing complexity of the pattern and symmetry. The top one is (or is most like) a long-spined urchin test.
Long-spined sea urchin Test / Skeleton Diadema antillarum (Keith Salvesen / Rolling Harbour) Long-spined sea urchin Test / Skeleton Diadema antillarum (Keith Salvesen / Rolling Harbour)

A BIT ABOUT SYMMETRY

Sea urchins are born with bilateral symmetry – in effect, you could fold one in half. As they grow to adulthood, they retain symmetry but develop so-called ‘fivefold symmetry’, rather as if an orange contained 5 equal-sized segments. The graphic above gives a good idea of how the interior is arranged inside the segments.

Long-spined sea urchin Diadema antillarum (Melinda Rodgers / Dive Abaco)

A FEW FACTS TO HAND DOWN TO YOUR CHILDREN

  • Urchin fossil records date the species back to the Ordivician period, c 40m years ago
  • In the ’90s the population was decimated and still has not recovered fully
  • Urchins feel stress: a bad sign that the spines here are white rather than black
  • Urchins are not only warm water creatures: some kinds live in polar regions
  • Urchins are of particular use in scientific research, including genome studies
  • Some urchins end up in aquariums / aquaria, where I doubt the algae is so tasty
  • Kindest not to prod or tread on them
  • Their nearest relative (surprisingly) is said to be the Sea Cucumber 

Sea Cucumber (Melinda Riger / G B Scuba)

ARE THEY EDIBLE?

Apparently they are eaten in some parts of the world; their gonads and roe are considered a delicacy. As far as I know, they are not generally on the menu in the Bahamas. Correction invited. Personally, I could leave them or leave them.

CREDITS: Melinda Rodgers / Dive Abaco (1, 2, 3, 6, 9) taken Abaco; Melinda Riger / G B Scuba (4, 10, 11) taken Grand Bahama; Keith Salvesen / Rolling Harbour (7, 8) taken Abaco; Wiki graphic (5) taken from internet. RESEARCH Fred Riger for detailed  information; otherwise the usual magpie pickings…

Long-spined sea urchin Diadema antillarum (Melinda Riger / G B Scuba)

‘TELLIN TIME’ – RISE AND SHINE: ABACO SEASHELLS


Sunrise Tellin Shell, Abaco Bahamas (Keith Salvesen Rolling Harbour)

‘TELLIN TIME’ – RISE AND SHINE: ABACO SEASHELLS

SUNRISE TELLINS Tellina Radiata

I included these pretty shells, with their striking pink radials, in a much earlier posBEACHCOMBING BIVALVES The ones shown here are larger specimens. Some call them ‘rose-petal shells’. The hinges (muscles) are very delicate, and for many of these shells that wash up on the beach, the two halves have separated naturally. 

Sunrise Tellin Shell, Abaco Bahamas (Keith Salvesen Rolling Harbour)

STs are not uncommon, and I recently found some beauties at Sandy Point. They can grow up to about 7 cms / 2.75 inches, and some of these ones were that length, or very nearly so. I realised after I had taken the photos that I should have used a coin for comparison.

Sunrise Tellin Shell, Abaco Bahamas (Keith Salvesen Rolling Harbour)

TELLIN: THE TRUTH

The occupant of each of these pretty shells is a type of very small clam. I have completely failed to find a photo of a nude one with its shell removed, but maybe these are never seen at all. The clams live on the sea-floor, often buried in the sand, and with the lid (mostly) shut. Then they die (or their shells are bored into by a predator and they are eaten) and the shells eventually wash up empty on the beach. There’s not much to say about them – they perform no tricks (some shell creatures do, such as backflips) and are believed to have vanilla sex lives (some shell creatures are quite inventive in this department).

Inside Story… not much to tell except (a) still very pretty & (b) possible predator bore-hole top rightSunrise Tellin Shell, Abaco Bahamas (Keith Salvesen Rolling Harbour)

WELL, WHAT ELSE IS THERE TO THEM, APART FROM BEING PRETTY & BEACHCOMB-ABLE?

  • The clams have 5 tiny teeth to chew up their staple diet, which is mainly plant material
  • These include one ‘strong’ tooth, and one ‘weak’ one, though how someone found it out remains a mystery
  • Tellins are native to the Caribbean and north as far as Florida.
  • They live mainly in quite shallow water, but can be found as deep as 60 foot
  • They have no particular rarity value, and are used for marine-based crafts

Sunrise Tellin Shell, Abaco Bahamas (Seashells . org)

PLEASE TRY HARDER TO HOLD MY ATTENTION

You know those lovely tellins you collected during your holiday on Abaco to take home to your loved ones? You may have committed a crime! You did take them, didn’t you? However the general rule – law, even – seems to be “in most countries it is illegal to bring back these shells from holidays”. However, you have been fortunate; the Bahamas has no specific prohibition on the removal of tellin shells, certainly not for personal use.

READER COMMENT: WHOOPS! ALSO, PHEW!

Sunrise Tellin Shell, Abaco Bahamas (Rhonda Pearce)

 

As ever, the very excellent Bahamas Philatelic Bureau has covered seashells along with all the other wildlife / natural history stamp sets they have produced regularly over the years. The sunrise tellin was featured in 1995. You can find more – much more – on my PHILATELY page.

Sunrise Tellin Shell 5c Stamp Bahamas (BPB)

All photos Keith Salvesen / Rolling Harbour; Rhonda Pearce Collection plus Seashells.Org, O/S Linnean Poster, O/S BPB stamp

Sunrise Tellin Shell, Abaco Bahamas (Keith Salvesen Rolling Harbour)

FLAMINGO TONGUE SNAILS: DECORATIVE CORAL-DWELLERS


Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

FLAMINGO TONGUE SNAILS: DECORATIVE CORAL-DWELLERS

FLAMINGO TONGUE SNAILS Cyphoma gibbous are small marine gastropod molluscs related to cowries. The living animal is brightly coloured and strikingly patterned, but that colour only exists in the ‘live’ parts – the so-called ‘mantle’. The shell itself is usually pale, and characterised by a thick ridge round the middle. These snails live in the tropical waters of the Caribbean and the wider western Atlantic. Whether alive or dead, they are gratifyingly easy to identify.

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

THE IMPORTANCE OF CORAL

Flamingo tongue snails feed by browsing on soft corals. Often, they will leave tracks behind them on the coral stems as they forage (see image below). But corals are not only food – they provide the ideal sites for the creature’s breeding cycle.

Flamingo Tongue Snails (Dive Abaco, Bahamas)Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

Adult females attach eggs to coral which they have recently fed upon. About 10 days later, the larvae hatch. They eventually settle onto other gorgonian corals such as Sea Fans. Juveniles tend to live on the underside of coral branches, while adults are far more visible and mobile. Where the snail leaves a feeding scar, the corals can regrow the polyps, and therefore the snail’s feeding preference is generally not harmful to the coral.

The principal purpose of the patterned mantle of tissue over the shell is to act as the creature’s breathing apparatus. The tissue absorbs oxygen and releases carbon dioxide. As it has been (unkindly?) described, the mantle is “basically their lungs, stretched out over their rather boring-looking shell”

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

THREATS AND DEFENCE

The species, once common, is becoming rarer. The natural predators include hogfish, pufferfish and spiny lobsters, though the spotted mantle provides some defence by being rather unpalatable. Gorgonian corals contain natural toxins, and instead of secreting these after feeding, the snail stores them. This supplements the defence provided by its APOSEMATIC COLORATION, the vivid colour and /or pattern warning sign to predators found in many animal species.

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

MANKIND’S CONTRIBUTION

It comes as little surprise to learn that man is now considered to be the greatest menace to these little creatures, and the reason for their significant decline in numbers. The threat comes from snorkelers and divers who mistakenly / ignorantly think that the colour of the mantle is the actual shell of the animal, collect up a whole bunch from the reef, and in due course are left with… dead snails and “boring-looking shells” (see photos below). Don’t be a collector; be a protector…

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

The photos below are of nude flamingo tongue shells from the Delphi Club Collection. Until I read the ‘boring-looking shell’ comment, I believed everyone thought they were rather lovely… I did, anyway. You decide!

Flamingo Tongue Snail Shell, Keith Salvesen AbacoFlamingo Tongue Snail Shell, Keith Salvesen Abaco

Image Credits:  Melinda Rogers / Dive Abaco; Keith Salvesen / Rolling Harbour

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)