WTF? (WHAT’S THAT FISH?) (5): THE FROGFISH


Frogfish (Adam Rees, Scuba Works)

WTF? (WHAT’S THAT FISH?) (5): THE FROGFISH

This ‘WTF?’ series started with a relatively conventional species, the REMORA. It has been getting progressively more bizarre. We moved onto an omnium gatherum of WEIRDO FISHES, then the remarkable LETTUCE SEA SLUG, and most recently the BATFISH. Time to ramp up the stakes: with many thanks to scuba expert Adam Rees for use permission for his terrific photos, I present… the FROGFISH.

Frogfish (Adam Rees, Scuba Works)

The frogfish is a kind of anglerfish found in almost all tropical and subtropical oceans and seas. There are about 50 different species worldwide, covering an astonishing range of strange appearances. They generally live on the sea floor around coral or rock reefs. In size they vary from tiny to about 15 inches long – although ‘long’ is a flexible concept because they are to an extent shape-changers in height and width.Frogfish (Adam Rees Scuba Works)

FROGFISH SUPERPOWERS YOU MAY WISH TO HAVE

  • INVISIBILITY CLOAK . Frogfish are masters of disguise and camouflage. This enables them to catch their prey with minimal effort and also to avoid predators. Their camouflage methods – broadly known as ‘aggressive mimicry’ – include
    • Ability to change colour for days or even weeks to mimic their surroundings
    • Getting covered in algae and other organic matter that matches their habitat or
    • Looking inherently like a plump rock or in some cases, plant

Fear for the life of the spider crabFrogfish (Adam Rees, Scuba Works)

  • IRRESISTIBLE ATTRACTION (just like that nice Mr Grey)
    • A sort of frontal dorsal fin called an illicium to which is attached a
    • Lure called an esca which may mimic a worm, shrimp or small fish etc and which is
    • Retractable in many species and
    • Regenerates if it gets mislaid

The ‘dollop of cream’ thing is the esca. Note the characteristic large mouthFrogfish (Adam Rees, Scuba Works)

Spot the escaFrogfish (wiki)

  • BUOYANCY CONTROL & SHAPE-SHIFTING
    • Most frogfish have a ‘gas bladder’ to control their buoyancy.
    • Some species can change shape or even inflate themselves by sucking in quantities of water in a so-called defensive ‘threat display’.

frogfish-black

Frogfish (Adam Rees Scuba Works) Frogfish (Adam Rees Scuba Works)

HOW DO FROGFISH REPRODUCE? 

Although not conventionally attractive creatures, frogfish clearly manage to reproduce. Little is known about the techniques in the wild, but one is probably ‘with care’, especially for a male frogfish who may not survive for long if he hangs around after fertilisation has taken place. It has been noted that females tend to select far smaller males to fertilise their huge numbers of eggs, perhaps for that very reason.

Frogfish (Adam Rees, Scuba Works)

FROGFISH FEEDING SKILLS – GOOD OR BAD?

When deploying the lure, potential prey that comes too close to that wide mouth stands no chance. A frogfish will strike in a fraction of a second. Frogfishes have voracious appetites for crustaceans, other fish, and even each other. I can do no better than borrow this vivid description of a feeding frogfish:

“When potential prey is first spotted, the frogfish follows it with its eyes. Then, when it approaches within roughly seven body-lengths, the frogfish begins to move its illicium in such a way that the esca mimics the motions of the animal it resembles. As the prey approaches, the frogfish slowly moves to prepare for its attack; sometimes this involves approaching the prey or “stalking” while sometimes it is simply adjusting its mouth angle. The catch itself is made by the sudden opening of the jaws, which enlarges the volume of the mouth cavity up to twelve-fold, pulling the prey into the mouth along with water. The attack can be as fast as 6 milliseconds. The water flows out through the gills, while the prey is swallowed and the oesophagus closed with a special muscle to keep the victim from escaping. In addition to expanding their mouths, frogfish can also expand their stomachs to swallow animals up to twice their size.

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HOW DO FROGFISHES GET AROUND? SWIM? WALK? CRAWL?

Frogfishes do not in fact move around a great deal. Using their camo advantages, they prefer to lie on the sea floor and wait for prey to come to them. As mentioned in the quote above, they may slowly approach prey using their pectoral and pelvic fins to “walk” along the sea bottom. They can swim using their tail fin (or in some species by simple ‘jet propulsion’ by forcing water out of their gills) but rarely do so – they don’t feed on the move, and they are adapted to the sea floor environment where they food is readily available. However their “walking” ability is limited to short distances.

frogfish-anglerfisch

DO FROGFISH HAVE OTHER COLOUR SCHEMES?

Indeed they do. In stark contrast to the camo species, some frogfishes are highlighter bright. Here are two of my favourite photos by Adam that show this clearly. I’ve no idea if these are a male and female. I suspect they are different species. I think the brown one is a striated frogfish and the other is… a yellow frogfish. Some people keep these creatures in  aquaria, but apparently it is impossible to sex them, and they have to be kept on their own for everyone’s peace of mind…

Frogfish (Adam Rees Scuba Works) Frogfish (Adam Rees Scuba Works)

FROGFISH INFOGRAPHICS

frogfishFrogfish Infographic 'Monsters of the Deep'

FROGFISH VIDEOS

These two videos, from Lester Knutsen and Daan Van Wijk respectively, show some of the characteristics I have written about above. Both are short and both are fascinating.

To read more about frogfishes and for some fabulous photos I highly recommend the website FROGFISH.CH You can reach the main page(s) but the link seem to be broken so I have not been able to contact Teresa Zubi, whose site it is. She clearly has a sense of humour and uses a neat pair of gifs which I hope she won’t mind my using…

Credits: All main photos, Adam Rees  of Scuba Works with many thanks; wiki for ‘spot the esca’, red quote & basic info; videos Lester Knutsen & Daan Van Wijk; Teresa Zubi for website & gifs; infographics, authors u/k

Frogfish Tee Shirt

FORAYS WITH MORAYS (2): SPOTTED IN THE BAHAMAS…


Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba)

FORAYS WITH MORAYS (2): SPOTTED IN THE BAHAMAS…

I’ve been neglecting the moray eels. It’s ages since I did a post about them, and it’s time to put that right. Specifically, time to take a look at Spotted Morays Gymnothorax moringa. These eels can grow up to 2 meters, and live mainly in the sub-tropical waters of the Atlantic. They are solitary creatures, most often seen with just their heads protruding from holes and fissures reefs and r0cks. They have interesting dental arrangements (see below) and their bite is one that, all things being equal, is probably best avoided… Here’s what to look for.

ADULT SPOTTED MORAYSSpotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba) Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba) Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba) Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba)

TOOTHSOME CRITTERS (FANGS FOR THE MEMORY…)Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba) Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba) Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba)

WICKLE BABY MORAY. MORAYKIN?BABY Spotted Moray Eel, Bahamas (Melinda Riger Grand Bahama Scuba)

Photo credits: all amazing photos courtesy of Melinda Riger of Grand Bahama Scuba; Props to ‘Earl the Eel’ who appears in some of them!

BAHAMAS WHALES & DOLPHINS IN ABACO & ANDROS WATERS


Melon-headed Whale breaching - BMMRO copy

Melon-headed Whale breaching – BMMRO

BAHAMAS WHALES & DOLPHINS IN ABACO & ANDROS WATERS

The Bahamas Marine Mammal Research Organisation (BMMRO)  has its HQ at Sandy Point, Abaco. We recently went out in their research boat, a RHIB, to spend an unforgettable day with Blainville’s beaked whales and bottlenose dolphins. I posted some of the dolphins HERE; and a two-part beaked whale post is a work in progress.

Male Blainville’s beaked whale with its extraordinary barnacle-encrusted teeth that protrude upwards from its lower jaw. The prominent beak is plainly visible. Sighted off the south-west point of Abaco during our second encounter with a group of these whales – the only male we saw that dayBlainville's Beaked Whale KS 1

Abaco waters are ideal for marine mammals, especially off the southern shores where the walls of the Great Bahama Canyon drop vertiginously down from the shallow coastal waters to depths of up to 3 miles below. This is one of the deepest ocean canyons in the world.  The area provides a rich source of food and nutrients for the whales and dolphins and many different species are regularly sighted there, from huge sperm whales to small pilot whales (including plenty of species I had never heard of before). 

Great Bahama Canyon Map edit

As the name suggests, the BMMRO’s remit extends far beyond Abaco. The researchers often spend time exploring and recording cetaceans in other Bahamian waters. For the last few weeks the team have been off Andros and have encountered quite a few target species. I have included a selection below taken within the last month to illustrate the importance of the area for a remarkable assortment of wonderful whales and dolphins.

BLAINVILLE’S BEAKED WHALEBlainville's Beaked Whale copy

DWARF SPERM WHALESDwarf Sperm Whales - BMMRO copy

PANTROPICAL SPOTTED DOLPHINSPantropical Spotted Dolphin - BMMRO Pantropical Spotted Dolphin leap - BMMRO copy

On board the research vessel, every sighting is recorded in detail – where possible by species, numbers, ages, sexes, and individual identifying characteristics. Thus ‘SW34′ may have a damaged fluke, whereas ‘RD49′ may have a long scar on its back. 

PILOT WHALESPilot Whale - BMMROPilot Whales - BMMRO copyPilot Whales 2 - BMMRO

The research boat is equipped with sound devices which, when the microphone is immersed, are capable of picking up whale or dolphin sounds from a considerable distance. It’s astounding to be able to listen in ‘live’ to the wide assortment of clicks and whistles produced as the creatures communicate with each other. The recorded sound patterns are studied and can often be matched to enable an individual animal to be identified. 

MELON-HEADED WHALESMelon-headed Whales - BMMRO Melon-headed Whale - BMMRO

RISSO’S DOLPHINRisso's Dolphin - BMMRO copy

Other work, including photography, is done underwater. Perhaps the most intriguing aspect is the collection of poop specimens, from which a great deal can be ascertained about the diet and health of an individual animal. I wrote about this task and the methods used a while ago inFAMILIAR FECES‘.

I’ll be writing more about whales soon. Meanwhile, here’s a short BMMRO video of a large group of melon-headed males. At the start, you can clearly hear communication sounds between them.

Credits: Charlotte & Diane of the BMMRO for taking us out with them and for all the photos except the male Blainville’s beaked whale (mine, for once!)

BRITTLE STARS: PRIMITIVE YET INCREDIBLY COMPLEX STARFISH


Brittle Star around a Tube Sponge ©Melinda Riger @ GB Scuba

BRITTLE STARS: PRIMITIVE YET INCREDIBLY COMPLEX STARFISH

BRITTLE STARS are closely related to starfish, and in particular to Basket Stars. They are commonly known as “serpent stars”, having 5 long, thin arms that may grow as long as 2 feet long. There are lots of different types of brittle star – at least 2000 – and they are found in every ocean on earth from the poles to the tropics. In Bahamian waters they a commonly found living on reefs.

Although these creatures look primitive, their structure, nervous systems, respiratory systems, digestive systems, sex lives and transportation methods are incredibly complex. Take it from me – I’ve just read about it all. So I’ve decided to pick a few aspects of these creatures to highlight rather than discuss the minutiae of their ossicles (tiny bones), madroporites (a sort of water filter / pressure balancer) and viscera.

You are most likely to see Brittle Stars clinging to coral or spongesSponge & Brittle Star ©Melinda Riger @GB Scuba

A DOZEN BRITTLE STAR FACTS TO PLAY WITH

  • The star has no eyes and no sense organs as we know them, but can detect light chemically; and (why would they need this?) sense smell through their ‘feet’… [Not a superpower I would prize, but still]
  • The mouth is on the underside of the central disc (‘body’) of 5 segments, each with a toothed jaw
  • The mouth is used both for ingestion and, putting it delicately, egestion. [Nor that superpower]
  • Stars eat tiny organisms suspended in the water or mini-worms, gathering them with their arms
  • If I have understood this, they breathe through their armpits, and can excrete from here also
  • The arms fit the main part with ball and socket joints, and are flexible in all directions
  • The genitals seem to be located in or between the armpits (lucky we are not descended from stars)
  • Stars readily regenerate lost arms until they lose the 5th – then they are in real trouble
  • This enables them to shed an arm in a predator attack, like a lizard its tail
  • Trials indicate that a jettisoned arm cannot regenerate from itself
  • They use only 4 arms to move along, with the fifth ‘steering’ out in front or trailing behind
  • Brittle Stars are inedible but non-toxic

Brittle Star on Green Rope Sponge ©Melinda Riger @ GB Scuba

Often, brittle stars will cling on inside a spongeBrittle Stars in sponge ©Melinda Riger @ GB Scuba

I quite liked this infographic from a source new to me, ‘Weird ‘n’ Wild Creatures Wikia’Brittle_Stars_front

Here is a great video from Neptune Canada of a brittle star fight on the ocean floor over the remains of a shrimp. If you watch the ones joining the fight, you will clearly see the locomotion method described above, with one limb pathfinding and the other four ‘walking’.

I’m not renowned for extreme sensitivity, so I feel no shame in showing mating brittle stars, courtesy of Channel Banks. It’s not exactly Lady Chatterley and Mellors, but the entwined arms are rather romantic, no?

Credits: all wonderful photos by Melinda Riger of Grand Bahama Scuba; BS infographic and viddys as credited

RED HIND GROUPER: BAHAMAS REEF FISH (25)


Red Hind Grouper Melinda Riger @ G B Scuba copy

RED HIND GROUPER: BAHAMAS REEF FISH (25)

The Red Hind is one of several grouper species commonly found in  Bahamas waters. Commonly for now, anyway. There is less information available about this species compared with other groupers, but sources seem agreed that it is (a) abundant and (b) IUCN listed ‘least concern’ but (c) heavily fished and (d) delicious.

Red Hind, attended by Cleaner FishRed Hind Grouper ©Melinda Riger @ G B Scuba copy 2

Red Hind Grouper ©Melinda Riger GB Scuba copy

One problem arises from the fact that Red Hinds form spawning aggregations in particular areas, making them vulnerable to fishing exploitation in those locations, and consequent population decline. Already, some of their spawning areas are protected.

Another threat comes from the degradation of coastal habitats coupled with increasing commercial and recreational fishing.  Red Hinds are targeted with speargun, hook and line, fish traps and nets. They may also be by-catch of other fishing operations. Fortunately Marine Protected Areas such as the ones in Abaco waters provide localised protection but these are not found throughout the Red Hind’s range. Closed seasons have been imposed in a few areas, another conservation method that has recently been introduced in the Bahamas for the Nassau grouper. 

Female spawning Red Hind Grouper (Univ of Puerto Rico:NOAA)

Getting the right balance between traditional fishing for food, and stock conservation is inevitably a tricky calculation. For the Red Hind, the factors that may result in the population decline of a plentiful species are in plain sight and will continue to be monitored by the various scientific research organisations involved…

OTHER GROUPERS YOU MAY ENJOY…

NASSAU GROUPER

TIGER GROUPER

BLACK GROUPER

Red Hind Grouper ©Melinda Riger @ G B Scuba copy 3

Credits: All images Melinda Riger at Grand Bahama Scuba except (4) NOAA / Puerto Rico Univ; research from several sources, tip of the hat to SCRFA

BOTTLENOSE DOLPHINS IN ABACO WATERS (2): MOTHER & CALF


Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas 12

Sometimes things happen that completely take my breath away. Here is one of those moments, from our recent trip with Charlotte and Diane in the BMMRO research boat. As we returned from whale-watching to base in Sandy Point and moved from the deep dark ocean to the bright blue shallows, we encountered a group of bottlenose dolphins. You can see my recent post featuring some of the adults HERE. That was exciting enough, as they played around the boat. Then another participant appeared… 

 Notice the dark area behind the adult dolphin… Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas

…which soon separated into a small dark splashing creature with its own fin cutting the waves…Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas

…and next seen keeping pace with its parentDolphin Mother & Calf, Sandy Point, Abaco, Bahamas

The sharp line between the light and the dark sea is where the sandy shallows abruptly give way to the deep waters of the Grand Bahama Canyon, a massive trench up to 2.5 miles deep with almost vertical cliff walls to the depths in some places

Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas

Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas

There were less active and splashy moments as the pair swam around togetherDolphin Mother & Calf, Sandy Point, Abaco, BahamasDolphin Mother & Calf, Sandy Point, Abaco, Bahamas

Then it was back to doing what they like best…Dolphin Mother & Calf, Sandy Point, Abaco, BahamasDolphin Mother & Calf, Sandy Point, Abaco, Bahamas

Then some more restful moments…Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas

And finally the pair moved away. On the far horizon, the Massive Mickey Mouse Cruise ship moored at ‘Disney’s Castaway Cay’ (formerly the sober-sounding Gorda Cay), where you can be a Pirate of the Caribbean. Or anyway a very happy Tourist. The choice is yours. Would you like fries with that?Dolphin Mother & Calf, Sandy Point, Abaco, Bahamas

And looking out to sea from the cheerful place that is Castaway Cay, I wonder if a small child was wondering “Ok, love Mickey and his Friends – but I’d also really love to see a wild dolphin swimming free… 

Disney Magic docked next to the Castaway Cay Family Beach copy

All photos RH (except Castaway, Wiki). Huge thanks to Charlotte, Diane and Bahamas Marine Mammal Research Organisation BMMRO for a truly wonderful day photo 2

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BOTTLENOSE DOLPHINS IN ABACO WATERS (PART 1)


Bottlenose Dolphins, Rocky Point, Abaco (Keith Salvesen : BMMRO) 7

BOTTLENOSE DOLPHINS IN ABACO WATERS (PART 1)

DCB GBG Cover Logo dolphin

This seems to be a excellent early Spring for dolphin and whale sightings in Abaco waters. I’ve noticed that people have been posting dolphin sightings on FB recently. In our brief window of opportunity each March, I usually reckon to see 2 or 3 dolphins at most – maybe crossing over to Hope Town on the ferry, or more probably on a fishing trip. This year we saw 2 groups of about 6 off Cherokee while fishing, including calves. On another day, 4 adults made a leisurely progress the whole length of Rolling Harbour while we watched from the balcony of the Delphi Club. I don’t think they have ever been so close to the shore there before. The best was to come.Bottlenose Dolphins, Rocky Point, Abaco (Keith Salvesen : BMMRO) 3

Near the end of our trip Charlotte Dunn and Diane Claridge invited us to go out with them on the BMMRO research boat. This is equipped with a hydrophonic system that can detect the bleeps, whistles and clicks of cetaceans, and record them for comparison with previous data. This enables particular animals to be identified from their vocalisations. The other method is to note particular features of an animal – damage to a fin, markings on the flank and so on. During the day C & D happily conversed in code: “Is that 132 over there?” “No, it’s got a nick in the fluke, it must be 127…”BMMRO Research Boat, Sandy Point, Abaco

As we returned in the RHIB from an amazing day spent at close quarters with beaked whales [more on these soon], we moved from deep dark blue ocean to sandy turquoise shallows. There, just off Rocky Point (near BMMRO HQ at Sandy Point) were half a dozen bottlenose dolphins, including a mother and calf. This post contains a small batch of photos of adults – there’ll be another post shortly featuring the calf… Bottlenose Dolphins, Rocky Point, Abaco (Keith Salvesen : BMMRO) 4Bottlenose Dolphins, Rocky Point, Abaco (Keith Salvesen : BMMRO) 1Bottlenose Dolphins, Rocky Point, Abaco (Keith Salvesen : BMMRO) 5

Here’s a taster for the next post – the calf, just visible close alongside its mother, was being given leaping practice. Watch this blog…

Bottlenose Dolphins, Rocky Point, Abaco (Keith Salvesen : BMMRO) 6

All photos RH. Huge thanks to Charlotte, Diane and Bahamas Marine Mammal Research Organisation BMMRO for a truly wonderful day (and for my cool sweatshirt!) photo 2

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