REDSPOTTED HAWKFISH: BAHAMAS REEF FISH (35)


Redspotted Hawkfish, Bahamas (Melinda Riger)

REDSPOTTED HAWKFISH: BAHAMAS REEF FISH (35)

The redspotted hawkfish (Amblycirrhitus pinos) is one of a number of species of hawkfishes found worldwide. This one is found on the sub-tropical and tropical reefs of the Western Atlantic, and is therefore a fish you might see when out snorkelling or (more likely) scuba-ing in the Bahamas. These are small creatures – adults are unlikely to exceed 4 inches in length.

Redspotted Hawkfish, Bahamas (Melinda Riger)

There’s not a whole lot else to report about them. They have no medicinal superpowers, for example, nor wickedly toxic spines. A quick scroll through the highways and byways of the interweb reveals that redspotted hawkfish are considered (rightly, I think) to be attractive, tend to be shy, enjoy perching on coral ledges, and are generally benign, except to smaller fishes to which they may show aggression or – worse – an appetite. 

Redspotted Hawkfish, Bahamas (Melinda Riger)

As you might predict, these pretty little fish are popular in the aquarium trade, where on any view they should be kept safe from predators. But maybe captivity is a little limited in opportunities for travel and exploration. They can be bought for (I just checked) $29.99. Or else left alone on a reef to take their chances.

Photo Credits: Melinda Riger / Grand Bahama Scuba, with thanks as per…

WTF? (WHAT’S THAT FISH?) 13: THE ROUGHHEAD BLENNY


Roughhead Blenny - Melinda Riger / Grand Bahama Scuba

WTF? (WHAT’S THAT FISH?) 13: THE ROUGHHEAD BLENNY

The WTF? series has looked at a number of bizarre reef denizens, and this little fish is certainly that. For a start, its ‘correct’ name is Acanthemblemaria aspera, an excellent challenge for saying 10 times very quickly **. And the name blenny comes from the Greek word for ‘slime’, quite enough to make the poor creature a laughing-stock in the reef community.

Roughhead Blenny - Melinda Riger / Grand Bahama Scuba

There are in fact several hundred blenny species and subspecies around the world. The roughhead is one of the most commonly found in western Atlantic subtropical and tropical waters. These are burrowing creatures, and they find holes in the nooks and crannies of coral reefs – and indeed in the coral itself. Brain coral seems to be a preferred location. Mollusc shells are another. Or they may just bury themselves in the sea floor. 

Roughhead Blenny - Melinda Riger / Grand Bahama Scuba

The  ‘roughness’ of head refers to the whiskery appendages (cirri) on a blenny’s blunt bonce – slender tendril or hair-like filaments. The word cirri is the plural version of the wispy high altitude cirrus clouds that streak the sky. These tendrils are shown clearly in some of the photos here, despite the tiny size of the fish (± 1 inch). 

Roughhead Blenny - Melinda Riger / Grand Bahama Scuba

THESE GUYS LOOK A BIT PRIMITIVE, AM I RIGHT?

To be precise – as far as is possible – blennies can be dated back to the Paleocene Era (or is it an Epoch?). This spanned a period 66 to 56 million years ago – around the time of the formation of the Rolling Stones.

Roughhead Blenny - Melinda Riger / Grand Bahama Scuba

You can find out more about roughheads in this excellent eHow video I came across after I’d written this post, to which I should now add that there is considerable colour variation in this subspecies, as you may already have noticed…

** You can also try this with ‘Red Lorry Yellow Lorry’. Yes I know. Maddening, isn’t it. You can’t stop now you’ve started. Sorry…

Credits: all photo, Melinda Riger; video, eHow

DUSKY DAMSELFISH: BAHAMAS REEF FISH (34)


Dusky Damselfish, Bahamas (Melinda Riger)

DUSKY DAMSELFISH: BAHAMAS REEF FISH (34)

The dusky damselfish Stegastes fuscus is one of a number of damselfish species found in Bahamian waters. These small reef fish, in adult form, are dark coloured as their name suggests. Their appearance is brightened by having distinctive blue edges to their fins.

Dusky Damselfish, Bahamas (Melinda Riger)

These fish feed mainly on algae, with a preference for red. They top up their diet with small invertebrates. Their value to the reef is that their feeding patterns help to prevent coarser seaweeds from becoming dominant in areas where these are prevalent. 

Dusky Damselfish, Bahamas (Melinda Riger)

Like many damselfish, the dusky is a territorial species, guarding its chosen area of seabed and the food sources within it by repelling intruders – often seeing off far larger algae-grazing fishes such as parrotfish and wrasse. Yet besides their aggressive traits, they are also rather cute, as photo #2 shows!

Dusky damselfish, Bahamas (Melinda Riger)

All photos: Melinda Riger / Grand Bahama Scuba

FORAYS WITH MORAYS (4): EXPRESSIVE FEATURES


Green Moray Eel (Melinda Riger / Grand Bahama Scuba)

FORAYS WITH MORAYS (4): EXPRESSIVE FEATURES

Time to return to those extremely expressive characters of the coral reefs, moray eels. Specifically, some green morays. One hesitates to anthropomorphise or ‘project’ human emotions onto creatures but with some species it’s hard not to do so. Following Mr Grumpy (or perhaps Mr Sad) in the header image, here are some close-ups of morays appearing to express their emotions, from happy to downright furious… Eels featured here include Judy and Wasabi, and I remind myself that the human habit of naming familiar wild creatures is itself a (perfectly harmless) form of benign animism. Exactly as with the regular banded piping plovers featured elsewhere in this blog that overwinter on Abaco’s beaches, such as Harry Potter, Bahama Mama and the delightfully-named Felicia Fancybottom…

Happy and contented?Green Moray Eel (Melinda Riger / Grand Bahama Scuba)Green Moray Eel (Melinda Riger / Grand Bahama Scuba)Green Moray Eel (Melinda Riger / Grand Bahama Scuba)

Something on my mind…Green Moray Eel (Melinda Riger / Grand Bahama Scuba)

Slightly amused?Green Moray Eel (Melinda Riger / Grand Bahama Scuba)

Pretty funny, actuallyGreen Moray Eel (Melinda Riger / Grand Bahama Scuba)

Ha ha…! Hilair!Green Moray Eel (Melinda Riger / Grand Bahama Scuba)

Watch it. You are beginning to bug us, Mr Harbour, with your stupid captionsGreen Moray Eel (Melinda Riger / Grand Bahama Scuba)

ANGRY. BACK OFF… NOW!!!Green Moray Eel (Melinda Riger / Grand Bahama Scuba)

THE NEXT POST WILL BE FROM ABACO HQ NEXT WEEK

Credits: All morayvellous photos, Melinda Riger / Grand Bahama Scuba except 6, Virginia Cooper / Grand Bahama Scuba

BLUEHEAD WRASSE: PRIVATE LIFE LAID BARE


bluehead_wrasse_thallasoma_bifasciatum_oregonstate-edu-pinterest

BLUEHEAD WRASSE: PRIVATE LIFE LAID BARE

The bluehead wrasse (or blue-headed wrasse) Thalassoma bifasciatum is a denizen of the coral reefs of the tropical waters of the western Atlantic Ocean. This bright little 4-inch fish is… a wrasse with a blue head. No more and no less. Unless it’s a juvenile. Then it is mainly bright yellow. It’s similar to BLUE TANG (aka ‘the Disney Dory’), which starts life bright yellow and grows up to be blue.

blue-head-wrasse-melinda-riger-g-b-scuba-copy

The species may be found singly, in pairs or small groups, or in schools.  They have an important role to play in the life of the reef. They are CLEANER FISH, vital to the health and wellbeing of the larger species they attend to, and thus of the reef itself. This is ‘cleaning symbiosis’, a relationship of mutual benefit. The big fish get cleaned; the little fish have a useful function and – importantly for them – therefore don’t get eaten. 

thalassoma_bifasciatum_bluehead_wrasse_san_salvador_island_bahamas-james-st-john-wiki

Having said that, blueheads are of course fair game as a snack for species that aren’t in the market for their cleaning services. And, unfairly, some species that are content to let cleaner gobies runtle around their gills and mouths are not so considerate of the wrasse. Some types of grouper and moray eel, for example.

bluehead_wrasse

TELL US EXACTLY SEVEN BLUEHEAD WRASSE FACTS

  • Juveniles can alter the intensity of their colour, stripes & bars
  • The bluehead wrasse is a ‘protogynous sequential hermaphrodite’
  • All are born female**. Some change sex to male during maturation (see below)
  • Food includes zooplankton, small molluscs and small crustaceans…
  • …and parasites / other juicy bits (fungal growths, anyone?) from bigger fish
  • The main threat to the species is coral reef degradation or destruction
  • The bright colours invite aquarium use, but the trade is not a significant one

** Some sources suggest some are born male and remain male. I’m not sure which is right

A juvenile bluehead (with feather-duster worms) – mostly yellow, with a pale underside
Bluehead Wrasse juvenile (wiki)

THE REMARKABLE SEX LIFE OF THE BLUEHEAD WRASSE

This is an unavoidable topic, I’m afraid. The bluehead’s sex life is the most interesting thing about them, and this is no time to be prudish. It is the subject of extensive scientific research, not all of which I have read since I decided to write about the species last night. Like many human relationships, “it’s complicated”, but in a conch shell it boils down to this:

  • To recap, BWs are born female and as they mature, some become male.
  • Males reach an ‘initial phase’ when they can breed in groups with females
  • Some males grow even larger & reach full colouration. This is the ‘terminal phase’
  • These large males aggressively chase away smaller ones & seek females to pair with
  • Their state of readiness (as it were) is signalled by colour changes
  • This behaviour is similar to that seen in many city centres in a Saturday night
  • The smaller fish have one bonus – their sperm count is higher than a dominant male
  • Prozac tests have shown that the drug reduces a dominant male’s aggression

blue-headed_wrasse_det (wiki)

As the excellent organisation OCEANA puts it: Bluehead Wrasses may reproduce in four different ways throughout their lifetime:  1) as a female in a group spawning event; 2) as a female in a pair spawning event within the territory of a large male; 3) as a small male in a group spawning event; and 4) as a dominant, terminal male in a pair spawning event within its own territory.

A cropped still from a video I took at Fowl Cay marine reserve. I’ve looked at dozens of images online and not found one that was all blue with a yellow end to its tail fin. Maybe it’s not a BW at all. Or it’s a different type of fish completely. Or perhaps it is just an all-blue alpha male.bluehead-wrasse-fowl-cay-mr-abaco

Credits & Sources: Melinda Riger; Adam Rees; James St John; Oregon State edu / Pinterest; Wiki images; self; Oceana; IUCN; magpie pickings

A bluehead wrasse passes the time of day with a gruntbluehead-wrasse-grunt-adam-rees

WATCHING NURSE SHARKS: BE PATIENT…


nurse-shark-8-16-melinda-riger-gb-scuba

WATCHING NURSE SHARKS: BE PATIENT…

I last took a look at nurse sharks nearly 3 years ago HERE. Time to revisit these creatures. Indeed, time for a close-up look. If you want to know more about this fascinating species, just click the link above.

The two strange items hanging down from the upper lip are sensory barbels
nurse-shark-melinda-riger-g-b-scuba

This side-view shows the shark’s relatively small mouth (for a shark anyway)nurse-shark-a-melinda-riger-gb-scuba

Admire the extraordinary texture of the the skin; and the tiny evil eye. Click or – better – double click on the image and you will see that the skin is in fact tessellated, made up of a mosaic of tiny squares and near-squares**nurse-shark-close-up-melinda-riger-g-b-scuba

This one is a baby nurse sharknurse-shark-baby-melinda-riger-gb-scuba

A juvenile nurse shark with a couple of grunts. Note the youngster’s paddle-like finnurse-shark-juv-melinda-riger-g-b-scuba

Head, mouth, jaws and teeth

 ginglymostoma_cirratum_head  

nurse-sharks-x2-plus-reef-sharks-melinda-riger-g-b-scuba

SO, THEY ARE SHARKS – ARE THESE GUYS DANGEROUS?

Not really, no. They aren’t looking to pick a fight; and they are not as territorially aggressive as the ‘bitey’ sharks are (or can be).  These slow-moving bottom-dwellers are generally harmless to humans. However, they can be huge—up to 4 metres —and have very strong jaws filled with thousands of tiny, serrated teeth. They will bite defensively if stepped on or bothered by divers who assume they’re docile. [As I said previously, “there are recorded instances of injuries caused to divers who have tried to pull nurse sharks by the tail. And serve them right, I say. Treat them with patience and respect!”] 

Nurse Shark ©Melinda Riger @ G B Scuba copy

**FUN FACT

M.C. ESCHER (the inspiration for Mr Hammer) was the master of tessellation in art. Click the link to explore the dedicated website. Maybe, sensationally, one day a shark will be found with skin like this… (Alert reader: “Actually, I think it most unlikely…”)

Escher fish

Credits: field photos by Melinda Riger, Grand Bahama Scuba; Wiki for the 4 mouth images & the Escher 

Nurse Shark ©Melinda Riger @ Grand Bahama Scuba

WTF? (WHAT’S THAT FISH?) 12: THE TRUMPETFISH


trumpetfishmelinda-riger-gb-scuba

WTF? (WHAT’S THAT FISH?) 12: THE TRUMPETFISH

It’s been a while since the previous post in the WTF? series, dedicated to the unusual or downright weird marine creatures that, when you see them swim into in the frame of your mask, prompt the involuntary exclamation “WTF?” (What’s That Fish?). Now, in all its glory meet… The Trumpetfish. These long piscine pipes are in no way related to the President-Elect and his tank of pet fish, but perhaps more explicably to seahorses and seadragons.

trumpetfish-melinda-riger-g-b-scuba

Trumpetfishes Aulostomus maculatus are as happy to swim upright as more conventionally, which helps them to blend in with vertical corals and sponges on the reefs in the tropical waters of the western Atlantic. Adults may grow to 3 foot long or more. These creatures come in a variety of colours – shades of red, orange, brown, green and yellow.

trumpetfish-adam-rees-scuba-works_

At the end of the fish’s long snout – see how far back the eyes are set – is a small mouth. Here’s how a trumpetfish goes about catching its prey (mostly small fishes):

  • Slowly swimming or drifting to a target from behind, and sucking it into its mouth
  • Staying suspended in the water, motionless, and waiting like a malevolent stick for a passing wrasse or similar to get too close
  • Swimming alongside larger fishes, which camouflages its presence and enables it to ambush small fish as they pass 
  • More generally, the trumpetfish has some ability to change its colour to blend with its surroundings – both a defensive as well as an attacking advantage

Trumpetfish (Adam Rees / Scuba Works)

The very excellent Peppermint Narwhal recently produced a series of posters in appreciation of particular species – and trumpetfishes and their kin in the Order syngnathidae were honoured. The PN’s cheerful website is well worth checking out for the sheer diversity of their ideas.

14991470_1159096584183417_5198894741175308852_o

MUSICAL NOTES

We are beginning to collect the makings of a decent orchestra here. The trumpetfish has a relative, the cornetfish, elsewhere in the world. The remarkable GUITARFISH has already featured in the WTF? series, as has a species of BASS, the Harlequin. And – hey! – what about the spotted DRUMFISH to lay down the beat? Maybe I need to compose a little jingle featuring these one day…

Credits: Melinda Riger (Grand Bahama Scuba); Adam Rees (Scuba Works)