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)

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


Caribbean Scorpionfish, Bahamas (Melinda Riger / G B Scuba)

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”.

Caribbean Scorpionfish, Bahamas (Melinda Riger / G B Scuba)

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 coralCaribbean Scorpionfish, Bahamas (Melinda Riger / G B Scuba)

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)”

Caribbean Scorpionfish, Bahamas (Ocean Frontiers Dive Shop)

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)

Scorpionfish, Bahamas (Ocean Frontiers Dive Shop)

THE BAHAMA NUTHATCH & THE BRINK OF EXTINCTION


Bahama Nuthatch, Grand Bahama (Bruce Purdy)

THE BAHAMA NUTHATCH & THE BRINK OF EXTINCTION

It’s quite a while since I posted about the Bahama Nuthatch (Sitta pusilla insularis) and the separation of its status from its cousin the Brown-headed Nuthatch HERE. I started by saying that it was one of the rarest birds in the Bahamas (or indeed anywhere), with a tiny population living only on Grand Bahama. It’s extraordinary to think that until the 1960s, these birds were common on the island. Then, for all the usual reasons, the  population began to decline “precipitously” (Tony White). By the 2000s, the most optimistic estimates suggested that about 1000 – 1200 mature birds might inhabit the pine forests. Other surveys showed far lower numbers. By now, the species had become highly vulnerable. Reports dwindled annually, and in some years only a handful sightings were recorded.

Bahama Nuthatch (Birdlife International, from Loma Linda Uni / Gary Slater)

Then in October 2016, Grand Bahama received a direct hit from Hurricane Matthew. It was as destructive as you might expect a violent Cat 5 storm could be. Without in any way seeking to diminish the far-reaching and devastating impact of the hurricane on the island (and elsewhere), I have to stick to the matter in hand here. The fact is that for nearly 2 years after Matthew and its trashing of the habitat, not a single BANU was sighted – this, despite many efforts to track one down in the known hotspot areas. It began to seem likely that  the little bird had simply been wiped out of existence. Since it is known nowhere else – not even on nearby Abaco – the Bahama Nuthatch had very probably become extinct.

Bahama Nuthatch (Erika Gates / Bahamas Weekly Article)

Fast forward nearly two years and suddenly there is the first hint of a glimmer on the horizon for these little birds. Finding one is already a needle-in-a-haystack quest. The target is shy and tiny – about 4 ins long and 10 grams; and the search area is vast – more than 30,000 hectares. Yet this summer, amazingly, some Bahama Nuthatches have been found and photographed, a most happy – and perhaps optimistic – outcome, and a deserved return for some serious survey work. Excited publicity has spread well beyond the usual online birding resources and into the mainstream press.

Bahama Nuthatch (Birdlife International)

THE KEY SIGHTINGS

JUNE 2016

The last recorded sighting of the Bahama Nuthatch (2 birds) before Hurricane Matthew was made in June 2016 by well-known Grand Bahama bird expert and guide, Erika Gates.

Bahama Nuthatch, Grand Bahama (Erika Gates) Bahama Nuthatch, Grand Bahama (Erika Gates)

MAY 2018

The May sightings involved a team of ornithologists from the University of East Anglia, together with experts from Birdlife International and the Bahamas National Trust. They planned a 3-month expedition to locate this species, among others. Meanwhile another team of local scientists and students also carried out a search, led by Dr. Zeko McKenzie of the University of The Bahamas (North) with the American Bird Conservancy.

The first team eventually made a sighting in May 2018, and the elusive bird was captured by Matthew Garner of UEA on camera. They also obtained brief and tantalising video footage (below). In all, the UEA team made six nuthatch sightings, and Bahamian team independently made five sightings (including seeing what appeared to be two together). 

Bahama Nuthatch (Matthew Gardner UEA)

JULY 2018

Erika Gates, with Martha Cartwright  and Zeko McKenzie, again managed to locate a single nuthatch to add to the earlier 2018 sightings. She too managed to get some photos of the bird.

WHAT OF THE FUTURE?

Among the May birds – however many there were in total – one was a juvenile. Combined with 2 adults seen at one time, that makes 3 birds. The extent of the period of study and search area of the May sightings (11 in all) make it likely that more than 3 birds were seen overall. Erika’s July bird, in a slightly different location, suggests another. Perhaps no more can be said than that there may be half-a-dozen Bahama Nuthatches extant in the world. It’s some comfort.

 Bahama Nuthatch (Birdlife International)However, as the May operation noted, ‘We also don’t know the sex of the birds. In many cases when birds dwindle to such small numbers, any remaining birds are usually male.’ The consensus of the articles I have read is that the handful of birds seen this summer, while a thrilling discovery, should not be seen as any guarantee against extinction. Further habitat degradation, more development, another hurricane, any one of these could be fatal to the species. The recent sightings are cause for some optimism but these little, highly vulnerable birds remain on the very brink of extinction. Those few people who have seen one in the wild have had a precious experience.

Bahama Nuthatch, Grand Bahama (Bruce Purdy)

THREATS TO THE SPECIES

  • Habitat loss / degradation from development, logging, forest fires & hurricanes
  • Invasive / introduced / feral species such as corn snakes, raccoons & cats
  • Competition from other more prolific species in a limited habitat

The Bahamas National Trust has produced an excellent video account of the whole story from Shelley Cant-Woodside HERE 

SOME LINKS TO THE STORY 

Photo credits: Bruce Purdy (1, 11); Gary Slater / Birdlife.org (2); Erika Gates / Bahamas Weekly (3); Erika Gates (4, 5, 7, 8, 9, 10); Matthew Gardner (6); Birdlife International (drawing); UEA & team (video)

Research credits include: Birdlife International / Birdlife.org; Lisa Sorenson; Tony White; Research Gate; IUCN; Bahamas National Trust; The Bahamas Weekly / Erika Gates; eBird; Loma Linda U; Science News; Sundry online publications; American Birding Association (and a bonus point for its brown-headed nuthatch behaviour article wittily entitled “Sex in the Sitta”)

GET ME A ‘CUDA – AND MAKE IT SNAPPY…


Barracuda, Bahamas (Melinda Riger / Grand Bahama Scuba)

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. 

Barracuda, Bahamas (Melinda Riger / Grand Bahama Scuba)

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.

Ling caught off the Dorset coast (Keith Salvesen)

Barracuda, Bahamas (Melinda Riger / Grand Bahama Scuba)

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.

Barracuda, Abaco Marls, Bahamas (Keith Salvesen)

Barracuda, Bahamas (Melinda Riger / Grand Bahama Scuba)

Barracuda, Bahamas (Melinda Riger / Grand Bahama Scuba)

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)


Sharpnose Puffer Fish (Melinda Riger / G B Scuba)

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).

Sharpnose Puffer Fish (Melinda Riger / G B Scuba)

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.

Sharpnose Puffer Fish (Melinda Riger / G B Scuba)

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.

Sharpnose Puffer Fish (Melinda Riger / G B Scuba)

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…Sharpnose Puffer Fish (Brian Lockwood)

* Not really

RELATED POST: PORCUPINE FISH

Photo Credits: All puffer fish taken by Melinda Riger of Grand Bahama Scuba except for the photo of an inflated one from recent Abaco permanent resident Brian Lockwood

OCTOPUSES: IN THEIR ELEMENT


Octopus, Bahamas (Melinda Riger / Grand Bahama Scuba)

OCTOPUSES: IN THEIR ELEMENT

We haven’t seen many octopuses in these parts for quite a while. Time to put that right. The seas of the Bahamas teem with many many marine species, but few are as fascinating or indeed versatile as the octopus. Don’t take my word for it, just watch ‘Finding Dory’ to see how amazing Hank the… [what’s that, Skippy? It’s fiction?]. As you were. That these extraordinary creatures even exist let alone thrive in our waters is a truly wonderful thing. Here are a few to admire – or in the case of the one below, to admire you.

‘Here’s lookin’ at you…’Octopus, Bahamas (Melinda Riger / Grand Bahama Scuba)Octopus, Bahamas (Melinda Riger / Grand Bahama Scuba)Octopus, Bahamas (Melinda Riger / Grand Bahama Scuba)

You can find out some more about octopuses – including the correct plural for ‘octopus’ – by clicking the links below. More importantly, you’ll see more of them too.

THE PLURAL OF OCTOPUS & RELATED CEPHALOPOD MYSTERIES

MARINE BAGPIPES FILLED WITH INK

OCTOPUSES: WORTH LEARNING TO SCUBA FOR

Octopus, Bahamas (Adam Rees / Scuba Works)

All octopedal photos: thanks to Melinda Riger / Grand Bahama Scuba (1 – 4) and Adam Rees / Scuba Works (5)

‘WELL SPOTTED’: PANTROPICAL SPOTTED DOLPHINS IN ABACO


Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

‘WELL SPOTTED’: PANTROPICAL SPOTTED DOLPHINS IN ABACO

Two species of spotted dolphin are found in Bahamas waters. The most common is the ATLANTIC SPOTTED DOLPHIN Stenella frontalis, a species confined to the Atlantic. Less commonly seen – though with a global range – are Pantropical Spotted Dolphins Stenella attenuata

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

The BMMRO research boat is out whale-spotting right now, and the team is finding a good variety of cetacean species, from dolphins right up to SPERM WHALE mother and calves. A couple of days ago, the pantropicals surfaced and these great shots of them were taken.

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

The two spotted dolphin species are very similar to the untrained eye. Identification is further complicated by the fact that both species start life without spots and go through stages ranging from no spots at all to completely spotted. These stages are sometimes referred to as ‘two-tone, speckled, mottled, and fused’. The pantropicals are relatively small, reaching lengths up to 7 feet and weighing c250 pounds at adulthood. Their beaks are longer and more slender than the familiar but larger bottlenose dolphin. The beak has a white tip, a useful identifier.

Atlantic Spotted and Pantropical Spotted range maps for comparison

The pantropicals favour shallower water by day, and at night they move to deeper water where they can dive down for food such as squid. Although they are IUCN listed as ‘Least Concern’ and their world-wide numbers are estimated to be abundant, they face the usual man-related threats to the species throughout their range, especially in the Pacific region. As we see time after time, complacency can turn to concern in a very short time.

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

THREATS TO THE SPECIES

  • Entanglement in fishing gear – captured as bycatch in the course of commercial fishing
  • Entangled in discarded fishing gear
  • Illegal feeding and harassment – this is a problem in particular locations eg Hawaii
  • Overexposure to and interaction with eager tourists in inshore areas
  • Hunting – these dolphins are prolifically hunted for food in several parts of the world
  • Hunting – they are caught ‘accidentally’ in large numbers in nets set for tuna
  • Persecution in eastern tropical Pacific fisheries, according to WDC
  • Pollution, plastic ingestion etc – basically, mankind’s negligence over 60 years or so
  • General habitat degradation, disturbance and marine noise pollution – mankind again

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

Credits: BMMRO for all photos; research credits NOAA; WDC