NASSAU GROUPER: ENDANGERED… AND PROTECTED


Nassau Grouper (Melinda Riger / Grand Bahamas Scuba)

NASSAU GROUPER: ENDANGERED… AND PROTECTED

Most creatures need some space for creative activity of one sort or another. Especially one particular sort, namely breeding. And for vulnerable and endangered species, this is especially important in order to maintain a sustainable population, and preferably to increase it year on year. Which is why there are closed seasons for certain fish, ensuring a time when they can be left alone to breed in peace and to perpetuate their species.

Nassau Grouper (Melinda Riger / Grand Bahamas Scuba)

The Nassau grouper Epinephelus striatus is just one of a number of grouper species that inhabit Bahamian waters. They are mostly found in the Northern Bahamas but only the Nassau grouper is on the IUCN Red List as an Endangered Species in need of protection.

Nassau Grouper (Melinda Riger / Grand Bahamas Scuba)

WHY ARE THESE FINE FISH ENDANGERED?

Sad to say, mankind is the main cause of the population fragility that has led to the official listing, and the imposition of a strict closed season for 3 months between December 1st and February 28th. Scientific studies have shown that commercial overfishing has reduced a thriving population to fewer than 10,000 mature fish. That may sound plenty to be going on with… until you consider that a net annual loss of only 10% would lead to extinction in a decade.

Nassau Grouper Infographic (Royal Defence Force)

10 CONVENIENTLY COLLECTED NASSAU GROUPER FACTS TO PONDER

  • An adult can grow to more than a metre long, and weigh 25 kg
  • They tend to be solitary daytime feeders, eating small fish & crustaceans
  • Their large mouths are use to ‘inhale’ or suck in prey
  • The colouring of an individual can vary from red to brown
  • These fish have little black spots around the eyes (I’ve no idea why).
  • Their habitat is in the vicinity of coral reefs, from shallows to 100 m deep
  • Spawning occurs in Dec & Jan during a full moon
  • Large numbers gather in a single location to mate in a mass spawning
  • These groupers are slow breeders, which compounds the overfishing problem
  • They are easy mass targets at spawning time; hence the need for a closed season

Nassau Grouper (Melinda Riger / Grand Bahamas Scuba)

Department of Fisheries information sheet (interesting if you have the time)

A Nassau Grouper glumly contemplates the possibility of extinctionNassau Grouper (Melinda Riger / Grand Bahamas Scuba)

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Nassau Grouper (Melinda Riger / . Grand Bahama Scuba)

Credits: all photos, Melinda Riger; Infographic by Royal Defence Force (tip o’ the  hat to Char Albury); Info Sheet, Dept of Fisheries

BAHAMAS REEF FISH (40): FOUR-EYED BUTTERFLYFISH


Four-eyed Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

BAHAMAS REEF FISH (40): FOUR-EYED BUTTERFLYFISH

Four-eyed (or foureye) butterflyfish (Chaetodon capistratus) are small, somewhat circular fish with an endearingly pointy little snout. They are one of several butterflyfish species found in Bahamian waters. On their sides are smart ‘go-faster’ chevrons, with the unmistakeable white-circled black ‘eye’ at the back. The real eyes, in the conventional position, are small and far less noticeable, not least because of the stripe that passes right through them.

Four-eyed Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

WHY THIS EXOTIC PATTERNING?

This type of misleading pattern is not uncommon in fishes and indeed in terrestrial creatures. It creates confusion in predators – and when this little fish is threatened it swims away with its large ‘eye’ prominent to the pursuer.  It acts as a warning and an off-putting feature that suggests ‘don’t eat me’. If you half-close your eyes and look at the image below, the large eyes stand out against the reef background and hint at a creature not to be tangled with. Why reef predators don’t rumble this ruse within minutes, I have no idea.

Four-eyed Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

WHAT IF THE RUSE FAILS?

Foureyes are very agile swimmers and can take advantage of narrow gaps and clefts in the reef  by swimming sideways or even upside-down to manoeuvre away from danger and to safety where the predator cannot reach it. 

Four-eyed Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

AND IF THAT DOESN’T WORK?

If the foureye is in deep trouble, it has an alternative cunning plan. It will turn and face the pursuer, head down and dorsal spines erect. This posture says both ‘I’m very spiny – watch out’ and ‘I’m coming atcher’. 

Four-eyed Butterflyfish, Bahamas (Lazlo Ilyes wiki)

AND IF THAT DOESN’T WORK? I’M WORRIED FOR IT NOW…

Curtains. It’s lunchtime, I’m afraid.

♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦

Foureyes are far from the only reef dwellers that have predator-confusing markings. In the image below, the foureye at the top is swimming with a larger BUTTER HAMLET, a species that also relies on an abnormal spot pattern to put off predators. This is a great capture, and it also illustrates how the smaller reef fishes can hang out together amicably.

Four-eyed Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

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Image Credits: 1, 2, 3, 4, 6, Melinda Riger / Grand Bahama Scuba; 5, Lazlo Ilyes

 

 

BAHAMAS REEF FISH (39): YELLOWTAIL DAMSELFISH


Yellowtail Damselfish (©Melinda Riger / Grand Bahama Scuba)

BAHAMAS REEF FISH (39): YELLOWTAIL DAMSELFISH

Yellowtails are just one of several damselfish species in Bahamas waters. These small fish are conspicuous not just for the bright tails that give them their name. More striking if anything – especially if seen underwater in sunlight against the coral – are the electric blue spots visible in both adults and juveniles.

Yellowtail Damselfish (©Melinda Riger / Grand Bahama Scuba)

The body of adults is dark blue to brownish to almost black 

The body of juveniles is blue

Yellowtails are a common and widespread variety of damselfish. They have a limited ability to change colour according to their surroundings, but with their bright tails and luminous blue flecks, it’s hard to see how they can look, to a predator, anything other than a tasty snack.

I have enjoyed seeing these little fish at Fowl Cay Marine Preserve, Abaco. The reef there makes for easy and rewarding snorkelling, with a wide variety of small and medium-size reef fishes to be seen. It’s an expedition I would definitely recommend to anyone wanting to see a healthy and active reef in a completely natural protected area.

I found that a video I took with a tiny camera was sadly of use only to myself. No one else would be able to make anything out due to the marked camera shake. Novices, huh? You are spared that: here’s a brief example of yellowtails swimming instead, showing the difference between juveniles and adults.

Credits: all photos, Melinda Riger / Grand Bahama Scuba; video from Desert Diving

‘RAISE AWARENESS’: SPOTTED EAGLE RAYS


Spotted Eagle Rays, Abaco, Bahamas (Gabrielle Manni)

Spotted Eagle Rays – Abaco, Bahamas

‘RAISE AWARENESS’: SPOTTED EAGLE RAYS

Mention of rays may conjure up thoughts of the familiar southern stingrays that populate the bright shallows and colourful reefs of the Bahamas. But there are other ray species out there gracefully patrolling the coral reefs – and one of these species is the spotted eagle ray (Aetobatus narinari).

Spotted Eagle Rays, Abaco, Bahamas (Catherine / Tara Pyfrom)

These fish (for that is what they are) are not uncommon. In fact they are found in tropical oceans worldwide (though there is a taxonomic distinction between the Atlantic version and the Pacific / Indo-Pacific ones). Note the concentration in the Caribbean sea.

Spotted Eagle Rays, Grand Bahama, Bahamas (Melinda Riger / GB Scuba)

Spotted eagle rays obviously have spots, but they are not notably eagle-like to look at. In fact, their snouts resemble a duck’s bill, and in some place they are less glamorously known as the duckbill ray. The ‘eagle’ part relates to the way in which they use their wings and appear to be soaring as they glide effortlessly through the water (see videos below).

Spotted Eagle Rays (Lazlo-photos Wiki)

Despite their global presence, these rays are categorised as ‘near-threatened’ on the IUCN Red List. Aside from vulnerability to predators including many types of shark, the rays may be caught as bycatch. In some areas they suffer entanglement in shark nets. And unsurprisingly there is a trade for them for large commercial aquariums. For the Atlantic species, Florida has taken a lead by banning fishing for, landing, buying or trading in spotted eagle rays. 

Spotted Eagle Rays, Abaco, Bahamas (Gabrielle Manni)

10 ESSENTIAL FACTS ABOUT SPOTTED EAGLE RAYS

  • They have 2 – 6 venomous barbed spines at the base of the tail
  • Adults are among the largest rays, with a 10 ft wingspan
  • They can leap clear of the water, and may do this more than once at a time
  • Occasionally they land in boats, to the consternation of all concerned
  • Their main diet is small fish and crustaceans, & sometimes octopuses
  • Their broad snouts are used to dig food out of the seabed as they forage
  • The rays are basically shy but may be curious of divers & snorkellers
  • They suffer from parasites, both externally and in their gills
  • Ray sex is quite physical, yet actual mating is brief (up to 90 secs…)
  • The female hatches her eggs internally, then her ‘pups’ are born live a year later

SPOTTED EAGLE RAY PUP

                          

Spotted Eagle Ray (John Norton Wiki)

 VIDEO SHOWCASE
These 3 short videos demonstrate the grace and beauty of spotted eagle rays as they glide elegantly around the reefs. The first (50s) was taken off Grand Bahama by Fred Riger (Melinda’s husband, for those who follow the underwater forays hereabouts); then one by Stephen Dickey (2:12) ; and finally one from Wildscreen Arkive (2:00).

WEIRD CREATURE CORNER

I have a lot of time for these cards produced by ‘Weird ‘n’ Wild Creatures’. In their unique style they are simple, educative and often give information nuggets not found elsewhere. The link is to their 4th series, Monsters of the Deep.

 

Photo credits: Gabrielle Manni (1), (5); Catherine & Tara Pyfrom (2); Melinda Riger / Grand Bahama Scuba (3); Lazlo-photos Wiki (4); Wiki (baby ray thumbnails); John Norton Wiki (6); Jacob Robertson Wiki (7); Weird ‘n’ Wild Creatures – card images. Videos as credited in text.

Spotted Eagle Ray, TCI (Jacob Robertson, Wiki)

QUEEN TRIGGERFISH AND GOOD RIDDANCE TO MARIA


Queen Triggerfish Bahamas (Melinda Riger / Grand Bahama Scuba)

QUEEN TRIGGERFISH AND GOOD RIDDANCE TO MARIA

I can think of no sensible connection between the colourful yet undoubtedly strange and grumpy-looking looking queen triggerfish Balistes vetula, and a hurricane. However, Hurricanes Irma and Maria have been rightly dominating the news and everyone’s thoughts for nearly 3 weeks now. And most of the recent posts from Rolling Harbour, for that matter. It’s not been a great time for looking at the birds, beasts and fishes. So, as Maria drifts eastwards and away from the Bahamas into the open ocean, it’s time for a splash of colour – and a fish I have not featured before. 

Hurricane Maria tracking at 11.00 EST on Sept 22

Queen Triggerfish Bahamas (Melinda Riger / Grand Bahama Scuba)Queen Triggerfish Bahamas (Melinda Riger / Grand Bahama Scuba)

The queen triggerfish, sometimes known as an Old Wife, is an Atlantic reef fish. This species is sometime fished for as game, and I know that a few have been taken from off the rocks at the south end of Delphi beach over the years – though perhaps not exactly on purpose.

Queen Triggerfish Bahamas (Mark Peter, Wiki)Queen Triggerfish Bahamas (Melinda Riger / Grand Bahama Scuba)

This fish typically is coloured with shades of  blue, purple, turquoise and green with a yellowish throat, with pale blue lines fins on head and fins. It’s minor superpower is to be able to change its coloration to some extent to match its reef surroundings and assist camouflage. Its favourite food is the sea urchin.

Queen Triggerfish Bahamas (Clark Anderson / Aqua-images)

Let’s hope this is the last post to feature anything about hurricanes for a good long time, as we think of all those still struggling to make sense of the terrible destruction they have recently experienced – in some places, twice over.

Credits: Melinda Riger / Grand Bahama Scuba; Mark Peter, Wiki; Clark Anderson / Aqua-images

CLEANING UP IN THE BAHAMAS: PEDERSON SHRIMPS


Pederson's Cleaning Shrimp, Bahamas (Melinda Riger, GB Scuba)

CLEANING UP IN THE BAHAMAS: PEDERSON SHRIMPS 

Pederson’s Shrimps Ancylomenes pedersoni (also known locally as Peterson’s shrimps), are one of several species of cleaner shrimp found in The Bahamas and more generally in the Caribbean seas. The species was named in 1958 by a multifaceted medico-oceanologist-zoologist Fenner A. Chace. He seems to have specialised in shrimps, finding distinct and differing species and naming them (not unreasonably) after himself (chacei);or colleagues and people he knew / admired; and in one case his wife. Mr Pederson was among them.

Pederson's Cleaning Shrimp, Bahamas (Melinda Riger, GB Scuba)

This tiny transparent creature with its vivid blue / purple markings and straggling pale antennae is unmistakeable, and helpfully cannot be confused with any other locally found shrimp species. Here’s an idea of its size, compared with a human finger and a blue parrotfish.

Pederson's Cleaning Shrimp, Bahamas (Melinda Riger, GB Scuba)

WHERE DO THESE SHRIMPS LIVE?

Their preferred home is… and it’s certainly a left field choice among sea creatures… in amongst the stinging tentacles of certain sea anemones. Not only do they not get stung, but of course they are well-protected by the defensive pain that their hosts can inflict. They are usually found singly or in pairs, but sometimes a whole colony may inhabit the same anemone.

SO EXPLAIN HOW THEY DON’T GET STUNG

Ok. The shrimps gradually build up a kind of resistance by pressing their bodies and antennae against the tentacles of the host anemone for increasing lengths of time, until they become immune. It’s like one of those kids’ electric buzzer / rheostat machines. Or a TENS machine (for those who know about backache).

 IS THERE A DOWNSIDE TO ALL THIS?

Yes indeed. If a shrimp moves away from its host for a few days, it has to start the process of immunisation all over again. So presumably they tend to stay home-lovin’.

Home sweet home for the Pederson shrimpsPederson's Cleaning Shrimp, Bahamas (Melinda Riger, GB Scuba)

SOMETHING ABOUT THE CLEANING, PLEASE

These shrimps offer ‘cleaning services’ to passing fish. When on duty, as it were, they wave their antennae vigorously to attract attention. A fish being cleaned will remain stationary and passive while external parasites and dead skin are removed. Many fish will open their mouths and gill covers for internal cleaning, with the tacit agreement that the cleaner will not become a snack. Shrimps often work in conjunction with small cleaner fish such as some species of goby and wrasse – see the links below for more on this topic, with copious images…

Pederson's Cleaning Shrimp, Bahamas (Melinda Riger, GB Scuba)

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Credits: all photos by Melinda Riger / Grand Bahama Scuba

BAHAMAS REEF FISH (38): SPOTFIN BUTTERFLYFISH


Spotfin Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

BAHAMAS REEF FISH (38): SPOTFIN BUTTERFLYFISH

Butterflyfishes are a large family of mainly colourful small fish somewhat like mini-angelfish. The spotfin butterflyfish (Chaetodon ocellatus) is one of several types of butterflyfish found in the western Atlantic Ocean; and one of half a dozen or so you are likely to see nosing around the coral reefs of the Bahamas.

Spotfin Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

The name ‘spotfin’ derives from the dark spot on the dorsal fin. At the front end, there is a distinctive black vertical stripe that passes right through the eye. Combined with the vivid colouring, predators are in theory confused or warned off.  The spotfin’s superpower (on a modest scale) is that at night, a change of appearance occurs in adults. The dark patch on the dorsal fin increases in size, and dark bands appear on the body. This seems to be in order to provide further protection during the darker hours.

Spotfin Butterflyfish, Bahamas (Melinda Riger / G B Scuba)

The spotfin above has an isopod attached to it, a type of crustacean with a segmented body. Primitive fossils of these creatures have been dated back some 3m years. Want to know want this one is up to? These things “are mostly external parasites of fish or crustaceans and feed on blood, having piercing and sucking mouthparts and clawed limbs adapted for clinging onto their hosts”.

Soldierfish photobombs a spotfin. Or maybe it’s vice versa?Parasitic species are mostly external parasites of fish or crustaceans and feed on blood. The larvae of the Gnathiidae family and adult cymothoidids have piercing and sucking mouthparts and clawed limbs adapted for clinging onto their hosts.

Reading about this particular species of  butterfly fish, I discovered that the spotfin “is very common and very hard to maintain in a tank” –  as if the two facts are somehow connected. So might they be coarse or vulgar, and thus unsuitable companions for better bred and perhaps sensitive aquarium fish? As it turns out, it may be because they are vulnerable to predation, and so can coexist only with peaceable tank friends. 

Spotfins are perfectly happy swimming upside down; and their party trick apparently is to rise to the surface and squirt a jet of water in the air. Sadly, I couldn’t come up with a photo of this…

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Credits: All fab photos by Melinda Riger / Grand Bahamas Scuba