BAHAMAS REEF LIFE (1): FRENCH ANGELFISH


French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

BAHAMAS REEF LIFE (1): FRENCH ANGELFISH

The massive destruction and dislocation caused on both Abaco and Grand Bahama by Hurricane Dorian is well-documented. The regeneration of both islands is making unsteady progress towards a stability that still seems many months away. In many locations it is still ‘two steps forward, one step back’. It remains a moot point whether ‘normality’, as it was just over 2 months ago, will ever be quite the same again.

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

We know how things are on land. As far as Abaco is concerned, few people can say how the coral reefs have been affected by the massive storms. Boats that were not flung ashore were sunk instead. Marinas and their infrastructure all but disappeared. 

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

Dive Shops, like so many thriving businesses in MH, have been reduced to rubble by this cruellest of extreme tropical storms. For the time being at least, they are damaged beyond use. I have seen no reports about the conditions in – for example – Fowl Cays National Park, a coral and reef-life rich marine preserve that was directly in the hurricane’s path. It may be weeks before an assessment can be made.

French Angelfish juv, Grand Bahama (Melinda Riger/ G B Scuba)

Happily, Melinda and Fred Riger of Grand Bahama Scuba have very recently been able to reopen their business. Melinda is, as regular readers will know, a wonderful underwater photographer. She kindly gives me the freedom of her extensive photo archive, accumulated over many years. The focus today is on French angelfish on the reefs of Grand Bahama.

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

Many of the photos here have been taken during the last 3 weeks or so, as diving becomes more of a daily exercise and customers are able to return to explore the underwater world of the reefs. Adult French angelfish have handsomely decorated flanks and golden eye-rings. The small striped ones with blue flashes on their fins are juveniles.

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

There are three angelfish species in the northern Bahamas – Queen, Gray and French. I have chosen to feature French angelfish because as it happens the juveniles of the species found since Dorian by Melinda and Fred may provide some insight into the subsurface effects of this huge storm.

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

As is evident from Melinda’s recent photos, the reefs off the south coast of Grand Bahama are relatively unscathed. Corals that she and Fred planted after the last hurricane have ‘taken’ and remain in place. However the juvenile fish now being seen nosing around the reefs in quantity may tell a story of disruption elsewhere.

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

The juvenile angelfish – as with the young of many other species – tend to live in the relative safety of the mangroves as they grow towards adulthood and are ready to move to the reefs. However, the unusual numbers of juveniles seen in the open during recent weeks suggest that the storm-damage to mangrove swamps in shallower water has unexpectedly displaced the juveniles to the reefs. 

French Angelfish, Grand Bahama (Melinda Riger/ G B Scuba)

This theory seems to apply to juveniles of other species recently encountered. What can be said is that, if even if displaced, there are plenty of healthy juvenile as well as adult fish around. And the justifiable  fears of serious damage to the corals have not been borne out. It remains to be seen whether a similar situation exists in Abaco waters.

French Angelfish juv, Grand Bahama (Melinda Riger/ G B Scuba)

Credits: all fantastic photos, Melinda Riger / Dive Abaco. It’s great that you have been able to reopen the business and restart having been forced to suspend operations completely.

French Angelfish juv, Grand Bahama (Melinda Riger/ G B Scuba)

IS THIS THE REAL LIFE? OR IS THIS JUST FANS AT SEA?


Purple sea fan, Bahamas (Melinda Riger / Grand Bahama Scuba)

IS THIS THE REAL LIFE? OR IS THIS JUST FANS AT SEA?

I wrote the original post on this theme, with its somewhat Bohemian and rhapsodic title, a while back. It was put together at a time of sunshine, normality and optimism. The 2019 hurricane season was far in the future, and the prospect of one – let alone two – of the finest islands in the Bahamas being virtually eradicated overnight was unthinkable.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Right now, in the aftermath of the devastation wrought by Hurricane Dorian, and as the communities gradually start on the long road to recovery, the priorities remain personal and community safety, food, fresh water, medical supplies and access to all the other necessities that the major relief operation has so effectively enabled. However, as gradual improvements to daily life are achieved, so a degree of interest in the natural world is returning.

Purple sea fan, Bahamas (Melinda Riger / Grand Bahama Scuba)

The despoliation of the land is there for all to see, visible even from space. As yet – as far as I know – no one has had the time or opportunity, or even a boat and the right equipment to investigate below the surface of the sea. What of the reefs: the bright darting reef fish; the larger denizens of the deep; the corals, sponges and anemones? The massive Cat 5 storm caused an unprecedented 23′ surge. It’s hard to see how the reefs can have remained unaffected, and there must be the possibility that the THIRD LARGEST BARRIER REEF in the world will have been altered irrevocably.

Purple sea fan, Bahamas (Melinda Riger / Grand Bahama Scuba)

Since Dorian, the related organisations have been unable to operate. Abaco’s ‘Dive Abaco’ was virtually annihilated along with the rest of Marsh Harbour. Grand Bahama Scuba has just reopened, although it may take a while before dive trips are anywhere back to normal. This post contains beautiful photos from both the Melindas concerned, taken in happier times before the dark cloud swept over the islands just one month ago.

Purple sea fan, Bahamas (Melinda Riger / Grand Bahama Scuba)

NOTES FROM THE PRE-DORIAN PAST

The waters of Abaco teem with myriads of fish that depend on the coral reefs for shelter and safety, for breeding, for growing up in, and for nourishment. Sea fans (or gorgonians, to use the technical name) are animals too. They may look like plants and stay rooted to the spot, but like anemones these ‘soft corals’ are creatures of the reef and essential indicators of its health.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

At the moment it can still be said that the static (‘sessile’) members of the Abaco reef community are relatively unscathed by the impact of (and I don’t want to get into any arguments here) whatever causes mass bleaching and the death of reefs elsewhere in the world.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)  Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

The purple sea fan Gorgonia ventalina (classified by Linnaeus in 1785) is one of the most common species of sea fan, and a spectacular one at that. The main branches are linked by a lattice of smaller branches. Below the ‘skin’ is a skeleton made of calcite compounded with a form of collagen. 

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Sea fans are filter-feeders, and have polyps with eight tiny tentacles that catch plankton as it drifts past. They develop so that their orientation is across the prevailing current. This maximises the water passing by and consequently the supply of food as the fans gently wave in the flow.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)  Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Gorgonians have a chemical defence mechanism that protects against potential troublemakers. The main effect is to make themselves unpleasant to nibble or uproot.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

One species impervious to this deterrent is the fascinating FLAMINGO TONGUE SNAIL (more of which quite soon). Other ‘safe’ species include the fireworm and BUTTERFLYFISHES.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

One benefit of sea fans to mankind is that their defensive chemicals have been discovered to provide the basis for drug research and development, specifically in the field of  anti-inflammatories. Another benefit, of course, is that they are very beautiful to look at. And in bad times, that can only be good .

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)    Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Most of the photos featured are by courtesy of Capt. Keith and Melinda Rogers of the well-known local scuba dive and snorkel centre DIVE ABACO, located in central Marsh Harbour. As prime enablers of reef exploration in Abaco waters, it can truly be said that they too have plenty of fans.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Credits: Melinda and Keith Rodgers / Dive Abaco, Marsh Harbour; Melinda and Fred Riger / Grand Bahama Scuba (1, 3, 4, 5)

** The answer to the questions in the Title is… it’s both!

FINALLY, A SPECIAL FAN FOR ABACO AND GRAND BAHAMA

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

BLUE CHROMIS: A FLASH OF COLOUR ON THE REEF


BLUE CHROMIS: A FLASH OF COLOUR ON THE REEF

I’ve gone pictorial for today because I have only got my phone with me while we are away. Composition is slow, close to decomposition – and the comms connection is close to disconnection

Blue chromis (Chromis cyaneus) belong to the same group of fishes as damselfishes. These unmistakeable, bright reef denizens are very visible despite their tiny size. These fish are shoalers, so out on the reef you can enjoy them flickering around you as you swim along or hang in the water to admire the corals.

Like many a pretty and easily captured small fish that can be monetised once removed from its natural home environment, the blue chromis is popular for aquariums, and for humans to keep in their own home environments, unselfishly feeding them concocted food.

Blue chromis are adaptable and sociable, and will happily swim with other small reef fishes (as above). My own favourite combo is chromis mixed in with sergeant majors. But a shoal of them (mostly) alone is pretty special too….

I cynically mentioned ‘concocted’ food earlier. Here is one online care instruction for looking after them: “They are omnivores, meaning that they eat both meaty and plant based foods. They are not difficult to feed and will eat a variety of regular aquarium fare, frozen, live, and sometimes even dry food. Feeding them a variety of foods will help them retain their color in captivity. They sometimes feed on the algae in the tank”. 

If you are tempted to rescue some from their reef habitat, rest assured that: They have been known to spawn in captivity. Blue chromis can usually be obtained for about $10-15. And don’t hold back on the frozen food (though maybe warm it up a bit before feeding time).

Credits: Melinda Rodgers / Dive Abaco; Melinda Riger / G B Scuba

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)

IS THIS THE REAL LIFE? OR IS THIS JUST FANS AT SEA?


Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

IS THIS THE REAL LIFE? OR IS THIS JUST FANS AT SEA?

The waters of Abaco teem with myriads of fish that depend on the coral reefs for shelter and safety, for breeding, for growing up in, and for nourishment. Sea fans (or gorgonians, to use the technical name) are animals too. They may look like plants and stay rooted to the spot, but like anemones these ‘soft corals’ are creatures of the reef and essential indicators of its health.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

At the moment it can still be said that the static (‘sessile’) members of the Abaco reef community are relatively unscathed by the impact of (and I don’t want to get into any arguments here) whatever causes mass bleaching and the death of reefs elsewhere in the world.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)  Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

The purple sea fan Gorgonia ventalina (classified by Linnaeus in 1785) is one of the most common species of sea fan, and a spectacular one at that. The main branches are linked by a lattice of smaller branches. Below the ‘skin’ is a skeleton made of calcite compounded with a form of collagen. 

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Sea fans are filter-feeders, and have polyps with eight tiny tentacles that catch plankton as it drifts past. They develop so that their orientation is across the prevailing current. This maximises the water passing by and consequently the supply of food as the fans gently wave in the flow.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)  Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Gorgonians have a chemical defense mechanism that protects against potential troublemakers. The main effect is to make themselves unpleasant to nibble or uproot.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

One species impervious to this deterrent is the fascinating FLAMINGO TONGUE SNAIL (more of which quite soon). Other ‘safe’ species include the fireworm and BUTTERFLYFISHES.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

One benefit of sea fans to mankind is that their defensive chemicals have been discovered to provide the basis for drug research and development. It’s tempting to say that by way of gratitude, we pollute the waters they need for their very existence. So, consider it said…

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)    Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

All the photos featured are by courtesy of Capt. Keith and Melinda Rogers of the well-known local scuba dive and snorkel centre DIVE ABACO, located in central Marsh Harbour. As prime enablers of reef exploration in Abaco waters, it can truly be said that they too have plenty of fans.

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

Credits: Keith and Melinda Rodgers; Dive Abaco @DiveAbaco, Marsh Harbour, The Bahamas ** The answer to the questions in the Title is… it’s both!

Purple Sea Fans, Abaco, Bahamas (Dive Abaco / Keith & Melinda Rogers)

BAHAMAS REEF FISH (49): BANDED BUTTERFLYFISH


Banded Butterflyfish, Bahamas (Melinda Riger / GB Scuba)

BANDED BUTTERFLYFISH – BAHAMAS REEF FISH (49)

The banded butterflyfish (Chaetodon striatus) is one of several butterflyfish species found in Bahamas waters. There are links to some of the others at the end of this post. The reason for the name is obvious. The purpose of the patterning (striatus) is to act as an adaptive anti-predator defence when seen against the varied landscape of the coral reefs that are its home. 

Banded Butterflyfish, Bahamas (Melinda Riger / GB Scuba)

These little fish tend to be found either singly or in pairs. Two of them together may play a form of chase game among the corals and anemones of the reef. 

Banded Butterflyfish, Bahamas (Melinda Riger / GB Scuba)

Banded butterfishes, like their cousins, have a varied diet that includes small crustaceans, worms, and coral polyps. They also have a valuable role on the reef by acting a cleaner fish for larger species like grunts, tangs and parrot fish. This sort of relationship, where one party benefits from this kind of interaction , is known as ‘commensalism’, one of the 4 types of symbiotic relationship.

Banded Butterflyfish, Bahamas (Melinda Riger / GB Scuba)

RELATED LINKS

LONGSNOUT BUTTERFLYFISH

BUTTERFLYFISHES (RH guide to reef, banded, four-eyed & spotfin)

REEF FISH INDEX gateway to loads of colourful finny species

WHAT’S THAT FISH? A handy resource

FLORENT’S GUIDE A ditto

Banded Butterflyfish, Bahamas (Melinda Riger / GB Scuba)

Credits: Melinda Riger / Grand Bahama Scuba

LETTUCE SEA SLUGS: SOLAR POWERED ‘CRISPY BLISSFUL HEAVEN’


Lettuce Sea Slug, Bahamas (Melinda Riger / G B Scuba)

LETTUCE SEA SLUGS: SOLAR POWERED ‘CRISPY BLISSFUL HEAVEN’

The Lettuce Sea Slug Elysia crispata (transl. ‘Crispy Blissful Heaven’) was No.3 in the ‘WTF’ ‘What’s That Fish’ series (despite not actually being a fish at all). It is not by any means the weirdest creature featured so far but it is nonetheless an animal whose appearance excites curiosity. Unless you see one moving, it could easily be mistaken for a plant. Maybe even lettuce. It is in fact a SACOGLOSSAN.

Lettuce Sea Slug, Bahamas (Melinda Riger / G B Scuba)

The name ‘sacoglossan’ literally means ‘sap-sucker’. This group (or ‘clade’) comprises small gastropod mollusks that ingest the cellular content of algae (which isn’t really sap).

WHY WOULD THEY DO THAT?

Because they are… SOLAR POWERED slugs

Lettuce Sea Slug, Bahamas (Melinda Riger / G B Scuba)

WHAAAAA…..?

As I mentioned when I last visited these remarkable creatures, this isn’t a technical forum and too much science hurts my head. This species primarily lives off algae. May I give you the word KLEPTOPLASTY to drop lightly into your conversation? In a couple of sentences, algae / algal content is eaten but only partially digested. Certain elements are stored to produce photosynthesis by which light is converted to energy (cf plants) and the slug can in effect live and move around without food. You could entertain your neighbour at dinner (or maybe on public transport, why not?) by summarising the process as “chloroplast symbiosis”. Meanwhile, I’m fetching a beer. Two beers.

Lettuce Sea Slug, Bahamas (Melinda Riger / G B Scuba)

HOW DO THEY REPRODUCE?

This topic doesn’t seem to have excited much investigative interest, and there’s not much specific information about it. What there is sounds unnecessarily complicated, so I am just going to say authoritatively ‘they do it like many other slug species’ and hope that covers it. The pair shown below may be exploring the possibilities, or at least trying to work out which end is which. One is easy to tell, but the other? Time to make our excuses and leave…

Elysia_crispata_(Lettuce_Sea_Slug_pair) Nick Hobgood

HOW FAST, EXACTLY, DOES A LETTUCE SEA SLUG MOVE?

This rather beautiful video from ‘CORAL MORPHOLOGIC STUDIO’ will reveal all. You’ll soon see that progress is very slow. I recommend watching the first 30 seconds and you’ll get the idea. If you choose to persist, you will see the slug sort of turn and move off to the left.

DO SAY:        What an intriguing creature. It’s a true wonder of marine nature.

DON’T SAY:  Any good in a mixed salad?

Lettuce Sea Slug, Bahamas (Melinda Riger / G B Scuba)

Credits: Melinda @ Grand Bahama Scuba, Nick Hobgood, Coral Morphologic Studio, Laszlo Ilyes wiki

Lettuce Sea Slug (Laszlo Ilyes)