TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

January 15, 2021 by Rolling Harbour

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.

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

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.

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.

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.

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

SHARK ATTACKS – ABACO, BAHAMAS, & BEYOND

August 3, 2020 by Rolling Harbour

SHARK ATTACKS – ABACO, BAHAMAS & BEYOND

Over the last couple of weeks or so I have been getting a lot of hits for Shark Attack information. There have been 2 or 3 recent incidents including a tragic (and very rare) death in Maine, which may well account for this. The Shark Attack details I have accumulated and posted over the years are buried in an historical sub-sub-page, so to make things easier I have rechecked and updated the latest data resources and their links, and put them in a mainstream post. This is it.

DATABASE UPDATE 2020

INTERNATIONAL SHARK ATTACK FILE

PRIMARY RESOURCE

This resource is the portal to a mass of current, recent, and historical data, presented with authority and clarity. It provides undoubtedly the most comprehensive and accessible global shark-incident data of all.

Last year I included informative screen-shots taken from this site. For now I am confining the information to the most useful direct links. More work for the reader, perhaps, but also a better chance to explore and understand the hows, whens and wherefores of shark-related incidents – and how best to avoid the situation in the first place.

SITE LINK

https://www.floridamuseum.ufl.edu/shark-attacks/

BAHAMAS-SPECIFIC

https://www.floridamuseum.ufl.edu/shark-attacks/maps/na/bahamas-antilles/

“The 2019 worldwide total of 64 confirmed unprovoked cases were lower than the most recent five-year (2014-2018) average of 82 incidents annually. There were five fatal attacks this year, two of which were confirmed to be unprovoked. This number is in line with the annual global average of four fatalities per year“

MENU SELECTION

Maps & Data Contributing Factors Shark Attack Trends

What are the Odds? Reducing Your Risk

For anyone thinking of entering waters where sharks live – eg scuba divers, spear-fishers, swimmers, boaters – with relatively little experience or knowledge, these links will be incredibly useful. Local knowledge is well worth having as well. A young friend of ours, an intern on Abaco, was warned against spearfishing at a particular location: “Fish there, you’ll get ate”. He did. He very nearly was.

“Humans are not on the menu of sharks. Sharks bite humans out of curiosity or to defend themselves”

The SRI produces a downloadable Global Shark Attack File that provides:

A downloadable incident log by country
A downloadable incident log chronologically
A world map of encounters categorized by provoked vs. unprovoked, incidents involving boats, air & sea disasters and questionable incidents
To read any basic case report, open the Chronological file, click on the case number (column A) and the report will open as a pdf file

SHARK SPECIES (CONCISE OVERVIEW FOR EACH SHARK)

http://www.sharkattackfile.net/species.htm

BAHAMAS-SPECIFIC STATS

http://www.sharkattackdata.com/gsaf/place/bahamas

ABACO-SPECIFIC STATS

http://www.sharkattackdata.com/gsaf/place/bahamas/abaco_islands

Credits: All great shark photos – Melinda Riger / Grand Bahama Scuba; ‘Infest’ sticker design, Tracie Sugo

A FINAL THOUGHT

EEL-SPOTTING: FORAYS WITH MORAYS (7)

December 9, 2019 by Rolling Harbour

EEL-SPOTTING: FORAYS WITH MORAYS (7)

MORAY EELS are plentiful around the reefs of the Bahamas. Some species, anyway. The ones you are most likely to encounter are green morays, and the spotted morays shown here. Less common are chain and golden-tail morays and, rarer still I suspect (because I have only one image in the archive…) is the ‘purple-mouth’.

Despite their moderately intimidating appearance – an adult may grow to 1.5 meters or more, with sharp teeth at the front end – these eels are not especially aggressive unless provoked. Best to assume that all humans will behave respectfully around them and remember that people are the intruders in the eels’ domain.

Morays tend to be loners of the reefs, but they do gather in groups from time to time. And as shown below, they will also hunt with other species, for example this tiger grouper.

Sharp-eyed, sharp-toothed

Looks friendly enough…

A long and surprisingly large body, generally concealed in the crevices of the reef

Credits: Melinda Riger / Grand Bahama Scuba

Lurkin’ Good

INTERNATIONAL SHARK WEEK? IT’S SO OVER… EXCEPT HERE

August 6, 2019 by Rolling Harbour

INTERNATIONAL SHARK WEEK? IT’S SO OVER… EXCEPT HERE

There’s never a day without a ‘Day’, nor a week without a ‘Week’. Almost all creatures under the sun are celebrated in some regular calendar-based time-frame. With the exception of No-see-ums: I’ve checked – there is no national or international Ceratopogonidae Day in any online calendar.

By a mere 2 days, I have missed Shark Week, a happening tied in with the Discovery Channel, and heralded by an amusing trailer that features no actual sharks… So, belatedly, here are some cool shark photos to enjoy, in case you didn’t get enough of them last week, or (like me) had other fish to fry.

“I’m so glad we agreed to watch each other’s backs…”

Meet Nurse Betty, as she is known to divers

MANGROVES: THE SHARK NURSERY

As all children are taught and some adults know, the mangroves that grow in the shallow waters around the islands of the Bahamas are of enormous ecological significance. This isn’t the place to expand on that now, but it is worth mentioning that the mangrove swamps are the nurseries of young sharks (‘pups’) until, as juveniles, they are old enough to leave the safely of their home for deeper waters. Check out the short video below.

Spot the REMORA hitching a ride on this shark’s back

Nurse shark – note the twin barbels (cf recent Goatfish article)

HAMMERHEADS FROM BIMINI

These wonderful photos were all taken in Bahamian waters. Melinda Riger of Grand Bahama Scuba is, as ever, the star snap-getter of sharks (and indeed all other marine creatures). Special thanks are also due to Grant Johnson / 60poundbullet and Neal Watson / Bimini Scuba Center for occasional use permission of photos – especially of hammerheads – that are, well, eye-popping. Video from ‘ZeroEye’

MEET ARNOLD: BE A BAHAMAS BLACK GROUPER GROUPIE

June 11, 2019 by Rolling Harbour

MEET ARNOLD: BE A BAHAMAS BLACK GROUPER GROUPIE

The Black Grouper, like all its cousins, has the twin disadvantages of being fished for sport and fished for food. As demand for grouper on the menu rises, so does its vulnerability. The species is described as a ‘slow breeder’, so a depleting population has less chance of sustaining numbers. The consequence is an exponentially diminishing stock of the species. The equation is simple: fewer fish means less and less stock replenishment.

Formerly plentiful, these groupers (like other grouper species) have moved from an IUCN listing of ‘Least Concern’ to ‘Near-Threatened’. Whatever effect climate change may be having on the oceans, stock depletion of this noble species also has more direct human causes.

An adult black grouper’s diet consists of small fish and squid. Juveniles feed primarily on crustaceans. However, certain tiny reef fish – blennies and gobies for example – are important to the species as ‘cleaners’. You can read about their significance by clicking CLEANING STATIONS.

The service performed by tiny fish on large ones (not only groupers) is an example of a symbiotic relationship known as ‘mutualism’**, in which both parties benefit (the little fishes get gacky bits of grouper to eat). The cleaners are able to do their work inside the gills and even the mouth of the host without being at risk.

The NASSAU GROUPER has a defined and enforced closed season to help maintain numbers. It will be interesting to see if the same protection is eventually extended to the black grouper and indeed to other grouper species.

** The other two types of symbiotic relationship are commensalism, in which only one species benefits while the other is neither helped nor harmed; and parasitism, where one creature (the parasite) gains, while the other (the host) suffers.

RELATED POSTS

Credits: all photos Melinda Riger of Grand Bahama Scuba

BAHAMAS TURTLES: BE AWARE BUT DON’T BEWARE

May 23, 2019 by Rolling Harbour

Green Turtle Eye (Melinda Riger / Grand Bahama Scuba)

GREEN TURTLE WATCHING

BAHAMAS TURTLES: BE AWARE BUT DON’T BEWARE

MAY 23 is another one of those ‘species awareness’ days. Somewhere in the world, it seems that every day of the year has a creature to be aware of. As the Sixth Extinction looms (the one we’ve promoted in basically two generations), a state of heightened awareness is where we should all be at.

TURTLES BY ADAM REES / SCUBA WORKS

That’s not an end in itself of course – it’s merely the first step to doing something about the species in question… and beyond that, every species. We’ve screwed up their world for them. Awareness is just a wake-up call to action. Support a cause. Join an organisation or group. Support campaigns. Sign up. Write stuff. Do stuff. Don’t do other stuff. Even wearing a “Save the Great-crested Newt” T-shirt would be better than nothing.

TURTLES BY MELINDA RIGER / GRAND BAHAMA SCUBA

Back to the turtles. I have featured a few great sea turtle photos (none of them mine) to concentrate the mind on today’s special species – one of the most loved and admired of the sea creatures of the Bahamas archipelago. If they go, we humans may not be far behind (but at least we won’t have stomachs full of plastic trash).

TURTLES: HAPPY TOGETHER!

Credits: Melinda Riger, Adam Rees, Virginia Cooper – and to all for their work in revealing the wonderful world beneath the ocean waves

ROCK BEAUTY: BAHAMAS REEF FISH (52)

May 10, 2019 by Rolling Harbour

ROCK BEAUTY: BAHAMAS REEF FISH (52)

I last featured the cheerfully-coloured Rock Beauty Holacanthus tricolor 2 or 3 years back. Time has passed; new photos exist; new people have signed up to follow this eclectic menagerie (thank you both). Time for another look at these beauties, which also happen to be cuties.

Look at the little guy above – posing for Pixar, adorably hoping to star in Part 3 of the Nemo / Dory trilogy

These fish are a small species of angelfish. Seen swimming around the reefs they are unmistakeable, not least because of their bright yellow hi-viz jackets, remarkable blue eyeliner and blue-black lippy.

Rock Beauties look like prime candidates for anyone’s aquarium, but their picky dietary requirements and tendency for aggression make them unsuitable.

They are highly specialised feeders, needing marine sponge in their daily diet. They are also prone to chase their tank-mates and nip them. On balance, they look more fetching nosing about the coral anyway.

WHAT DO JUVENILES LOOK LIKE?

Juvenile rock beauties are cute mini-versions of the adults, only more yellow and with yellow lips. In some development stages, they have a smart blue circle around the dark patch on their sides (bottom image).

NOTE Rock Beauties have no known kinship with Chrissie, Debbie, Lita, Joan, Jennifer, Stevie, Madge and the rest of the accredited ‘Rock Beauties aka Chicks’

NOT A TRUE ‘ROCK BEAUTY’ (no offence, Lita)

A TRUE ROCK BEAUTY

Credits: Melinda Riger, Grand Bahama Scuba; WP

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

April 19, 2019 by Rolling Harbour

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

HOW DO THEY FEED?

Diagram of adult solitary tunicate

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.

IF THEY CAN’T MOVE, HOW DO THEY… (erm…) REPRODUCE?

APART FROM BEING STATIONARY & ASEXUAL, ANY OTHER ATTRIBUTES?

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

‘REEF ENCOUNTER’ 1: GRAY ANGELFISH

April 4, 2019 by Rolling Harbour

‘REEF ENCOUNTER’ 1: GRAY ANGELFISH

Today I learn from a cheery message from WordPress that my illustrated ramblings have been going on for exactly X years, where X is greater than 5 but less than 10. Time to start a new theme: channelling my inner Noel Coward, I am introducing a new mainly pictorial series provisionally called ‘Reef Encounter’. All the awesome beauty of reef life will be here.

In the past I have posted about GRAY ANGELFISH, one of three kinds of angelfish found in the northern Bahamas. Today, I am featuring some more recent images of these pretty creatures. Note in particular the striking shape and colour of their mouths, the blue being found also on the fin edges at the back.

On this otherwise gray fish, you’ll also find touches of yellow on the face and the edges of the front fins. In the header image there’s another little fish in the bottom right corner. Not a baby angelfish, but a FOUR-EYED BUTTERFLYFISH – a species that will feature in own right in due course

All fabulous photos by Melinda Riger / Grand Bahama Scuba

WTF? (WHAT’S THAT FISH?) 17: YELLOWHEAD JAWFISH

February 7, 2019 by Rolling Harbour

WTF? (WHAT’S THAT FISH?) 17: YELLOWHEAD JAWFISH

It’s been a little time since I added to the WTF? series, in which some of the more outlandish reef denizens come under close scrutiny. Jawfishes (Opistognathidae) come into this category, not least because of their interesting ways with their eggs. Also, they tend to stick upright out of the substrate, which is not especially fishy behaviour.

More than 50 species of jawfish are found around the world. In the Bahamas, you are most likely to encounter the Yellowhead (or Yellow-headed) variety. And if you think they look slightly… primitive, that’s because they are. In fact, their forebears (forefishes?) originated in prehistoric times, specifically the Miocene era (a lot of million years ago, I didn’t count exactly).

These rather extraordinary little fish superficially resemble certain types of BLENNY. Their modus operandi is to burrow down into sandy, gravelly or other loose substrate. They do so by cramming their mouths with sand and spitting it out to one side. By this means they form a tunnel of sorts in which they can live, and from which they can emerge, or half-emerge and take a look around them. As they do so, they hoover up passing food, mostly plankton and suchlike.

If something looks threatening while they are feeding or having a look around, they can simply duck down into their burrow for safety. They guard their patch against rivals, and behave ‘territorially’ in the jawfish community. One method is to ingest and and then eject sand or gravel at a would-be intruder.

YES, BUT WHERE IS THE REAL ‘WTF?’ FACTOR HERE?

Good question. With a good and original answer. These little creatures are so-called ‘MOUTHBROODERS‘, meaning that they carry their eggs in their mouths. Depending on the species, females, males or even both parents (don’t try this at home) will do this at or after fertilisation. In effect the eggs are safely incubated until they hatch as fry. Then they are on their own.

ARE THERE ANY DRAWBACKS TO THIS UNUSUAL GESTATION METHOD?

Apart from accidentally swallowing the occasional potential junior, the eggs need aeration from time to time. This is achieved by expelling the eggs from the mouth, and quickly sucking them back in again. Try this very short video to see this rather improbable behaviour in action. It’s only 8 seconds blink and you’ll miss the action. The eggs hatch into fry in 8 – 10 days, after which both parents can relax. Until the next time.

Yellowhead Jawfish (Melinda Riger / Grand Bahama Scuba)

Photo Credits: all images from Melinda Riger / Grand Bahama Scuba except (4) Virginia Cooper / GBS; (5) Michael Wolf / Wikimedia; video, Alan Keller. Research: magpie picking, not excluding yet not limited to Wiki…

BAHAMAS REEF FISH (51): BLACK MARGATE

January 28, 2019 by Rolling Harbour

BAHAMAS REEF FISH (51): BLACK MARGATE

The black margate (Anisotremus surinamensis) is a type of GRUNT (see also PORKFISH) found among the reefs and rocks of (mostly) the western Atlantic seaboard, from Florida as far south as Brazil. They are relatively ‘shallow’ fish and they prefer to be close to place where they can live safely and avoid the predators that lurk in open or deep water.

Margates are not usually very large, mostly growing to between 18″ and 30″, although they can grow larger. Thanks to the awesomeness of Wiki and other reliable sources I can confidently report that “…the maximum recorded weight for this species is 5.8 kg (13 lb)“.

MAY WE HAVE THE TRADITIONAL 10 FUN FACTS PLEASE?

Local names include burriquete (Sp) and zapatero or burros (Mex)
There are 10 margate species world wide, including 2 Pacific versions
Their heads slope down to a notably thick lipped mouth in which they have strong teeth
Margates have erectile spines, presumably for defence (I’ve not tested that)
They like to shelter in caves and crevices, on ledges, and in wrecks (see pics)
Margates are ‘solitary fish’ or hang out in small groups
They are night-feeders on a diet of crustaceans, mollusks, smaller fish & urchins
Sadly for them, they are valued by commercial fisheries using baited drift fishing…
…and also targeted by anglers during the spawning season when they shoal (?unfair)
… and also caught as aquarium fish, adding to stock depletion

RELATED SPECIES

PORKFISH

Credits: all photos, Melinda Riger / Grand Bahama Scuba; research from magpie pickings and in particular the interesting mexicanfish.com

HAWKSBILL TURTLES: ENJOY THEM WHILE YOU CAN

January 3, 2019 by Rolling Harbour

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 on Hawksbill 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.

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

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

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

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

BAHAMAS REEF FISH (50): TOBACCO BASSLET

December 6, 2018 by Rolling Harbour

BAHAMAS REEF FISH (50): TOBACCO BASSLET

Welcome to #50 in the Bahamas Reef Fish series. I chose this fish to honour the landmark before thinking about its features. Grumpy. Also, associated with a narcotic and dangerous drug. And a fish one probably wouldn’t bother to smoke (even if one could get it to light underwater). In the Bahamas you’ll find these little fish around the coral reefs where they play their part as reef denizens, which includes being prey to larger species. If one looks them up online, however, the overwhelming impression from the websites and images available is that they exist largely for the benefit of the aquarium industry.

Tobacco basslets (Serranus tabacarius) – more commonly just called tobacco fish or tobaccofish – are related to the HARLEQUIN BASS(LET), a species that was most unfairly included as #9 in my parallel WTF? series among all the seriously weird sea creatures that feature in that category. A wrong I must right one day.

Tobacco fish are considered to be hardy, unaggressive (except towards the tiny fishes and crustaceans they feed on) but apparently they need quite a large tank to hold them. The ocean might be suitably large for the purpose. Especially as it seems that in an aquarium there needs to be a cover on top: “these fish are expert jumpers…“, as one source puts it…

BESIDES THE BAHAMAS & AQUARIUMS WHERE ELSE DO THEY LIVE?

APART FROM THE HIGH JUMP THING, ANY OTHER TRICKS?

Yes indeed. The Tobacco Basslet is hermaphroditic, like all other members of its genus.

DON’T LEAVE IT AT THAT… HOW DO THEY, YOU KNOW?

I didn’t want you to ask. All their FB pages say “It’s complicated“, but here’s a rough idea…

All individuals start life as simultaneous hermaphrodites (with sex organs of both sexes)
The largest fish lose their female functions and become active sperm-producing males
Each male leads a group of hermaphrodites and protects them from other males
This gives them exclusive rights to the female parts of members of their ‘harem’
Sometimes hermies may use their male bits to join in & release sperm – ‘streaking’
There are rarer mating strategies… Oh heck, please look at the abstract of a scientific paper for details. I had to! And all because you, gentle reader, asked that question.

With some relief, here is very short video. It probably doesn’t accurately show how Tobacco fish might behave on a Bahamian reef. In captivity, from the look of it, they get pushed around by bigger fish. But maybe, if their co-residents are carefully selected, the bonus is that they don’t risk getting eaten.

OPTIONAL MUSICAL INTERLUDE

There are no songs ever that mention tobacco fish or tobacco basslets (though lots involve bass). And more oddly, apart from a couple of old blues songs the only truly mainstream song about tobacco by name (as opposed to content) is Tobacco Road, a song as frequently and thoroughly covered as an aquarium tank containing jumpy tobacco fish.

Rare photos from the actual sea captured by Melinda Riger of Grand Bahama Scuba; Science Direct plus magpie pickings; Captive Aquatic Ecosytems (video)

I didn’t enjoy this article about me very much. I am NOT grumpy. Tobacco Basslet (Serranus tabacarius) Bahamas (Melinda Riger / GB Scuba)

BAHAMAS REEF FISH (49): BANDED BUTTERFLYFISH

November 22, 2018 by Rolling Harbour

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.

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 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.

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

Credits: Melinda Riger / Grand Bahama Scuba

BLACK DURGON: A TRIGGERFISH OF DISTINCTION

October 18, 2018 by Rolling Harbour

BLACK DURGON: A TRIGGERFISH OF DISTINCTION

The Black Durgon (Black Triggerfish) seems to be a fairly rare triggerfish in Bahamas waters. I say that not because I know, but because there is very little mention of them in a Bahamas context. In fact, the (not especially profound) research I have done suggests it is not (originally?) really native to the Bahamas region at all. Correction of this impression welcome!

These fish have the ability to change colour, according to their surroundings. Mostly, they seem completely black. However they have intricate blue markings to the head, and regular patterning on their flanks that resembles the sort of thing one idly doodles during a long and less then attention-holding phone call (or the ‘hold music’) – see Header Image. They also have dramatic pale stripes where their fins join the body.

These fish have a varied diet that includes small fish, squid and shrimps, with side-helpings of algae, zooplankton and marine plants. And…

FUN FACT (REALLY!)

The Black Durgon has been studied, of course. One piece of research discovered that they… erm… ingested the feces and vomit of a species of dolphin. Other reef fish in the area did so too, but the Black Durgon was much the keenest on this distinctive diet. So these are ‘offal-eating’ fish… and welcome to it. Here’s a short video to take your mind off it all…

I’d be interested to hear from anyone who has encountered these fish in Abaco waters. I ought to look further into their prevalence. Maybe they just don’t get much publicity. They need a new agent.

Credits: Photos by Melinda Riger / Grand Bahama Scuba except #3, Getty Images; Kwik-Viddy, Cassandra-Tel; inadequate research, Author

BAHAMAS SEA TURTLES: IN THEIR ELEMENT

October 11, 2018 by Rolling Harbour

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 reef Hawksbill Turtle, Bahamas (Melinda Riger / Grand Bahama Scuba)

A hawksbill snacking on a sponge

Interaction with other underwater species: gray angelfish and a rock beauty

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

WTF? (WHAT’S THAT FISH?) 15: SCORPIONFISH

September 13, 2018 by Rolling Harbour

WTF? (WHAT’S THAT FISH?) 15: SCORPIONFISH

The WTF? series is aimed at shedding light on fishes that are unusual. Or very unusual. Or puzzling, dangerous and maybe less than elegant in appearance. The scorpionfish is one such. It belongs to a large family, the Scorpaenidae, and many types are found throughout the world, especially in the Pacific and Indian oceans. LIONFISH, the newcomers to the western Atlantic, are a species of scorpionfish.

Just another rock on the seabed… Caribbean Scorpionfish, Bahamas (Melinda Riger / G B Scuba)

WHY ‘SCORPIONFISH’? THEY LOOK SCARY. ARE THEY DANGEROUS?

One feature common to many scorpionfish species is that they are highly venomous. As the name suggests, a sting is involved. Or several stings. These come from the creature’s sharp spines, which are coated with mucus, and are to be avoided. If you want to pet one, the dorsal, anal and pelvic fins are the ones to steer clear of – these all have venom glands at the base. The spines act like injection needles. Scorpionfish aren’t naturally aggressive (except to prey), but they know how to defend themselves if need be. If you get ‘got’, you are in for “extreme pain and burning sensation”.

DO THEY HAVE ANY OTHER TRICKS TO WATCH OUT FOR?

As many have written, scorpionfish are ‘Masters of Camouflage’. They are able to disguise themselves very effectively. Their appearance is a remarkably adapted to their surroundings, as if covered in a raggle-taggle of colourful algae. They can change colour to aid concealment. They can flick sand over themselves as they settle on the seabed. These ploys enable them to lie motionless on a coral reef or on the seabed, ready to ambush their prey. This consists mainly of small fishes and crustaceans, but really anything edible that will fit in their mouths is fair game.

Concealed against coral

HOW DO THEY FEED?

The large mouth of scorpionfishes has a particular function. They don’t have teeth because they have no need. A scorpionfish can open its mouth and its gills simultaneously, thereby creating an instant vacuum that will suck in its prey in a flash. I have seen this described as “a nearly imperceptible split-second movement (15 milliseconds)”…

THESE SCARY MONSTERS MUST BE HUGE, RIGHT? I’M KEEPING OUT OF THE WATER

Not so fast. When all is said and done – and in my view, most disappointingly – adult Caribbean Scorpionfish grow in the range of… erm… 7 – 14 inches. So now you are reassured, here’s a great short video from Ocean Frontiers Dive Shop, who kindly shared it on YT. I’ve used a couple of illustrative stills from it too.

ANYTHING ELSE WE NEED TO KNOW?

I can do no better than to turn to Card 81 to the excellent ‘Monsters of the Deep‘ series of trading cards (the link is to my MotD page). I do realise that this is a rather unscientific approach. On the other hand these guys pack memorable information into a very short space, and do it well. Note that you can get a reflex sting from a scorpionfish for up to a week after it has died. Eat dust, earthbound scorpions.

Credits: Melinda Riger / Grand Bahama Scuba (1, 2, 3, 4,); Ocean Frontiers Dive Shop (video from YT, 2 stills); Wierd (sic) Creatures / Monsters of the Deep (O/S)

FORAYS WITH MORAYS (5): THE GOLDENTAIL

September 3, 2018 by Rolling Harbour

FORAYS WITH MORAYS (5): THE GOLDENTAIL

The Goldentail Moray Eel Gymnothorax miliaris is one of the half-dozen moray species found in Bahamas waters. Adults range in length from about 1.5 to 2.5 feet, and they are creatures of the reefs and rocks of the western Atlantic. As far as I can make out, the goldentails are rather less common than green or spotted morays, the two main eel species of the Bahamas.

Like their moray cousins, goldentails likes to keep themselves to themselves, and lead largely solitary lives. That said, sometimes they have been observed hunting in a group. They live in holes, clefts, and caverns which they leave both during the day and at night to hunt for prey along the reefs, aided by an acute sense of smell. Their diet is mainly of crustaceans, mollusks, and small fishes.

ARE GOLDENTAILS DANGEROUS?

Like many other eels, goldentails secrete a protective mucus that contains a toxin, making them unattractive prey for large predators such a groupers and barracudas. They are also associated with ciguatera poisoning, the active ingredients of which are found in the mucus coating. They are sometimes found in aquariums – the associated sites give a warning of painful bites, because they have backwards-pointing teeth (aka prey traps) – see header image for a clear view of this.

Goldentail Moray Eel (Melinda Riger / G B Scuba)

CAN YOU EAT THESE FISH?

Well I wondered that too, so I checked. The answer seems to be yes, if you real really want to. Comments on forums include:

“Yes they are edible, I just ate one few weeks ago. Some parts are little bony and skinning it is a bitch. But the meat is very soft and white, delicious. Deep fry works”.
“After eating our moray eel something changed. The next morning, we were decidedly feeling ill. I won’t get into the details, but let’s just say that “gastrointestinal effects”
“…symptoms (of ciguatera) include gastronomic effects, and neurological effects which include headaches, numbness, paresthesia, muscle ache, and even hallucinations”.
“Before you can eat one you have to kill it. They are amazingly hard to kill. I would skip it.”
“I would rather eat a shoe”

So I’ll be moving straight on to the next course, please. Or just a Kalik would do, thanks.

RELATED POSTS

SPOTTED MORAY EELS

GREEN MORAY EELS

Credits: Melinda Riger / Grand Bahama Scuba (1, 2, 4); iStock / Getty Images (3, 5, 6)

GET ME A ‘CUDA – AND MAKE IT SNAPPY…

August 22, 2018 by Rolling Harbour

GET ME A ‘CUDA – AND MAKE IT SNAPPY…

It’s probably fair to say that barracudas are among the less kindly-disposed of the denizens of the flats and reefs of the Bahamas. They certainly rank high on the Rolling Harbour Tooth Avoidance Scale. The seemingly random nature of the razor sharp dental arrangements – different sizes, different angles, different directions – does not inspire confidence.

The worst fishing injury I have picked up so far – aside from multiple terrible injuries to pride from botched casts, mistakes, missed takes and lost fish – has come from a large ling. What I didn’t know until I had been cut when my finger went into its mouth was that the teeth are coated in anticoagulant. I bled all over the boat and spent the rest of the day getting through a large roll of paper towel and several improvised bandages (J-cloths). That wiped the smug smile off my face – pride in the catch came before a notable fall in my standard-issue blood quota.

When bonefishing in the shallow waters around the coast of Abaco, there are always ‘cudas to be seen. They are not the main target fish, but the boats always have a spinning rod in them, just in case… At some stage in the day, some people find it hard to resist the urge to chuck out a lure when ‘cudas are about. It’s not something I generally do, though occasionally my fly gets intercepted by a practice-sized ‘cuda.

A learner ‘cuda that took a bonefish fly

Earlier this year I was in a boat fishing with the legendary Robin Albury, a guide who generally doubles my usual modest catch rate. My boat partner and I were taking a lunch break, with an open cool box of snacks between us and a Kalik in our hands. Robin went to the sharp end with the spinning rod on the off-chance. In a flash he had seen a big ‘cuda, chucked out the lure onto the creature’s nose and caught it, almost in one movement. I put down my beer to watch the entertainment. Robin decided otherwise, and simply handed me the rod to play the thing. And boy, was that fun. I didn’t get the kudos of making the hook-up, but I had plenty of work to do… It took an excitingly long time to bring the strong and vigorous fish to the boat. Robin got to hold the fish, of course – after my ling experience, I was happy enough to let him mess with the dental arrangements.

Credits: Melinda Riger / Grand Bahama Scuba (1, 2, 4, 6, 7); Keith Salvesen / Rolling Harbour (3, 5, 6)

SHARPNOSE PUFFER FISH: BAHAMAS REEF FISH (47)

August 6, 2018 by Rolling Harbour

SHARPNOSE PUFFER FISH: BAHAMAS REEF FISH (47)

It’s more than 4 years since I last wrote about these intriguing creatures and their endearing ways. It’s time for another look, with a new batch of great photos too. This is a species that lends itself to the ‘Fun Fact’ treatment, a method that tells you at least as much as you probably need – or want – to know about puffers. The message to take away is, best not to handle one – let alone eat one – unless you know exactly what you are doing…

Sharpnose Puffer Fish (Melinda Riger / G B Scuba)

10 PUFFER FISH FACTS TO ASTONISH YOUR FAMILY & FRIENDS

1. Puffers can inflate their bodies in an instant by ingesting huge amounts of water and becoming water-filled balloons. Then their tiny spines stick out.

2. They need a startling form of defence (or ‘piscatorial superpower’ Linnaeus 1763*) like this because they can’t swim very well to escape from predators: it’s surprising and intimidating – and it also makes them hard to eat.

3. However, a persistent predator undeterred by the trick will find that the puffer contains a toxin (tetrodotoxin TTX) that is said to be ‘1,200 times stronger than cyanide’. One puffer fish has enough toxin to kill up to 30 humans (National Geographic).

4. Notwithstanding the risks, selected parts of a puffer fish are a delicacy in some cultures (known as ‘fugu’ in Japan). Specially trained chefs are used to avoid mass deaths among diners. The insurance premiums must be huge.

5. Sharks are thought to be the only species immune to the puffer fish, and are not much bothered by a small fish that can blow itself up.

6. Puffers have skin, not scales; most have toxic fins or spines of some sort, besides toxic innards. Bright coloured kinds are likely to be more toxic than their duller cousins. This warning colouration in creatures is known as aposematism.

7. It’s worth finding out what an uninflated puffer looks like before you try to pet a random passing fish and have a toxic encounter. There is as yet no known antidote.

8. In all, there are more than a hundred puffer species in the world, all found where there are warm shallow waters. At least 3 main species – sharpnose, band-tail and chequered – are found in the Bahamas.

9. Some puffer species are not toxic at all; and some – especially in Pacific waters – are far more toxic than others. That’s the region where they are treated as a delicacy.

10. I’ve checked several research papers but I can’t find an evaluation of the relative toxicity as between the Bahamas puffer species. However it’s clear that the sharpnose is certainly not one play with. Take care!

Q. SO WHAT DOES AN INFLATED PUFFER LOOK LIKE? A. THIS!

Brian Lockwood took his life in his hands to get this fantastic shot…