Video series: Take a Minute
In this video series, we invite you to “Take a Minute” to relax and refresh your mind and soul with visual meditation. Take a 1-minute break from whatever you are doing to immerse yourself in the beauty of our blue planet. For this minute, Yoeri selects one long shot to allow you to fully focus on one creature or seascape. Dive into the scene, feel the energy, open your heart, connect to the subject, look for details or simply get carried away!
Be here now. Take this one minute to be fully present, instead of analysing the past or planning the future. It is quite interesting to see how long and relaxing one minute can be as soon as we stay in that moment - fully aware, fully present, fully relaxed. Observing one long scene, in contrary to the bombardment of pictures, news and fast cuts we are getting on a daily basis, helps to calm us down, to ground and centre us. Sometimes all it takes is 1 minute to recharge.
Diving is our form of active meditation. Underwater we find happiness in the present moment. There are so many healing and soothing factors to the ocean. There is so much we love about diving and nature.
We will get to that. For now, enjoy!
Video gallery of the entire clip collection
Further down there are the separate clips with full descriptions listed - have it your way.
Take a Minute XLIX: Blue-lined philinopsis (Philinopsis speciosa)
Take a Minute XLVIII: Hairy Frogfish (Antennarius striatus)
Take a Minute XLVII: Hard coral polyps (Hexacorallia)
Take a minute XLVI: Leaf scorpionfish (Taenianotus triacanthus)
Take a minute XLV: Giant Moray Eel (Gymnothorax javanicus)
Take a Minute XLIV: Long-arm Octopus (Abdopus sp.)
Take a Minute XLIII : Tiger Shrimp (Phyllognatia ceratophthalma)
Take a Minute XLII : Ornate Ghostpipefish (Solenostomus paradoxus)
Take a Minute XLI: Goniobranchus kuniei
Take a Minute XL: Hawksbill Sea Turtle (Eretmochelys imbricata)
Take a Minute XXXIX: Whale shark (Rhincodon typus)
Take a Minute XXXVIII : Harlequin Crab (Lissocarcinus laevis)
Take a Minute to Relax XXXVII: Slender Filefish (Monacanthus tuckeri)
Take a Minute XXXVI: Feather Duster (Tube) Worm (Sabellastarte spectabilis)
Take a Minute XXXV: Roughhead Blenny (Acanthemblemaria aspera)
Single video clips with full descriptions
Take a Minute to Relax I
This shallow and sheltered part of the reef is perfect to start or or end a dive. Take a minute to let your eyes wander over the healthy and abundant corals. Gently moving closer to examine a group a Batfish (Platax) hanging out in one corner of the reef - simply taking their time to relax. Over the years we saw members this group of Batfish (also called Spadefish) growing up. So beautiful to continuously be one with nature - diving rules. So wonderful to see the positive impact of protected marine areas in Wakatobi.
Take a Minute to Relax II
We happily present our second clip of“Take a Minute”, a series of short films created to relax and refresh your mind and soul with visual meditation (longer description below). This 1-minute clip is featuring a nudibranch, an underwater sea slug, called Coryphellina rubrolineata. Take a Minute to look at all the beautiful details on this creature and how it eats this hydroid. Can you see the bite it took passing through the digestive tract?
We tell ourselves to be mindful, even when doing regular things in life, like eating. However, truly living in the moment, becomes so much easier underwater, not only is the marine life right there and then, but also we are more focused and aware of ourselves and our bodies. All our worries and (self-)doubts stay at the surface and hopefully you'll take your time to look and really observe the world around you. The overall picture (like the video clip two weeks ago: Take a Minute I) invites you to dream away. Details, like of this nudibranch, really lure you into the scene. Observing creatures and their behaviour is beautiful and relaxing in itself, but it becomes even more rewarding when we know their names and understand what they are doing.
The characteristic of aeolid nudibranchs like this Coryphellina rubrolineata are long, narrow bodies with numerous horn-like extension which are called cerata and serve as gills of these sea slugs. Nudibranch originates from the Latin word nudus meaning naked and Ancient Greek bránkhia for gills as nudibranchs have their gills exposed on their backs. The form of the cerata extends the surface for respiration (breathing) significantly, but the cerata is also used for defence. Like shown in this clip many aeolid nudibranchs feed on hydroids and their stinging cells (nematocysts) pass through the digestive system of some aeolids unharmed and are built into the tips of the cerata.
For more weird and wonderful clips, pictures and information on nudibranchs visit our website and take a look at the entry “Nudibranchs: Everybody’s darling” or watch more of the underwater clips Yoeri filmed for Devocean Pictures in the section videography or on our YouTube Channel.
Take a Minute to Relax III
It’s time to to relax again, and “Take a Minute” with the third clip of our series for visual meditation (longer description below). This 1-minute film is a visual treat on multiple levels. Beautifully captured, you can focus on the eyes of a purple-blotched mantis shrimp (Odontodactylus latirostris) and slowly discover more and more of this fascinating marine creature while the camera is zooming out.
Take a Minute to look deep into the eyes of this juvenile mantis shrimp. Mantis shrimps have the most complex eyes and visual system so far discovered in the animal kingdom. It’s almost like they can look into another dimension. 😉
The eyes on long stalks can be moved individually resulting in almost 360°view. Each eye can gauge depth and distance on its own by focusing on objects with three separate regions (trinocular vision). While human eyes have three types of photoreceptor cells, they have between 12 and 16 types. Mantis shrimp can perceive wavelengths of light ranging from deep ultraviolet (UVB) to far-red (300 to 720 nm), including fluorescent and polarized light.
This creature does not only amaze divers and photographers alike, but also scientists and engineers as they are learning more about the way these eyes function:
“Six species of mantis shrimp have been reported to be able to detect circularly polarized light, which has not been documented in any other animal, and whether it is present across all species is unknown. Some of their biological quarter-waveplates perform more uniformly over the visual spectrum than any current man-made polarising optics, and this could inspire new types of optical media that would outperform the current generation of Blu-ray Disc technology.” Wikipedia: Mantis shrimp
This juvenile purple-blotched mantis shrimp is a smasher. With their two raptorial appendages or clubs they can punch with the speed of a gunshot from a .22 calibre rifle. This rapid strike generates vapour-filled bubbles in the water between the appendage and the striking surface, called cavitation bubbles. These bubbles collapse and produce a measurable second hit after the instant forces of 1,500 newtons of the punch itself. Even if the initial blow misses the target, the shock wave of the collapsing cavitation bubble can be strong enough to stun or kill the prey.
Take a Minute to Relax IV
It’s time to “Take a Minute” again and to broaden the perspective on (marine) life with some visual meditation. Get into the groove and swing with this relaxed colony of garden eels. Unfortunately, worries and anxieties are on the rise. We do believe that nature is a beautiful way to calm the body and mind and nourish the soul. Luckily, in most countries, you are still allowed to leave the house for a walk in the woods. Our equivalent is a night dive tonight and, same as watching these garden eels dance, it will put a smile on our faces.
Garden eels (Heteroconger) are in favour of a sessile lifestyle. They only get out of their house to change over to another burrow. Anchored in their holes in the sand they live in colonies. In calm waters they go about their business, moving in any direction they like. The stronger the current the more the are forced to follow the same approach to conserve energy: Face into current and form their bodies into a question mark. As you can see we had a pretty relaxed end of the dive at the Liberty wreck in Tulamben, Bali (Indonesia), in February 2020.
If you can’t get into nature yourself, watch some more of our underwater clips, nature documentaries or put on some music to sing and dance your troubles away. After home office make time for some home disco! There is an added bonus to both of these approaches. Hopefully they put a smile on your face. A psychological study has shown that holding a smile during brief and acute periods of stress helps to reduce the body’s stress response, such as a higher heartbeat. For this effect to work the person doesn’t even have to feel happy, though we truly hope smiling in times of social distance actually contributes to everybody’s health and happiness. And the best: Smiling is contagious!
Take a Minute to Relax V
In this edition of the visual meditation sessions "Take a Minute", we would like to focus your attention on the skeleton shrimp. Although commonly named that way, they are in fact no shrimps at all. Caprellidae, as is their actual scientific name, are a Family within the Order of amphipods. Caprellids are easily distinguishable from other amphipods by their slender, elongated bodies, which allows them to virtually blend into their habitat consisting of fine filaments of seaweed, hydroids and bryozoans. With this ability, they also earned the nick name of "ghost shrimp". They are omnivores that often like to stand upright to catch their food floating by in the current, whilst anchoring themselves to something with 3 pairs of appendages, named pereopods. Most Caprellids are sexually dimorphic, with the males usually being far larger than the females.
In this particular shot, we see a male giving a "piggyback ride" to a female. They are about 2 cm in size. We thought this "uplifting" behaviour to be perhaps an example for us all during this difficult time, showing us that we should stand by, and help each other to get through this current situation ...
Take a Minute to Relax VI
In this visual meditation session of “Take a Minute”, we invite you to have a look at this “giant” among the little fellows. The Costasiella kuroshimae is a species of opisthobranch that is categorized as a sacoglossan sea slug, or sap sucking slug, due to its feeding behaviour. They can be found “grazing” on algae leaves, which earned them the nick name “Leaf Sheep”. Although most people these days know this creature under the name “Shaun the Sheep”, due to the uncanny likeness in “facial” expressions to the famous TV animation character. It is this adorable likeness that makes them one of the most famous nudibranchs today. This big superstar can grow up to a whopping 5 mm in size! So in order to fully enjoy an encounter with this aquatic “Shaun the Sheep”, one is advised to bring a magnifying glass. Otherwise one might be left with the same blank “Shaun the Sheep” expression on one’s face, when a dive guide points happily to a greenish speck on a leaf of algae. This tiny creature has the ability to extract the chloroplasts from the food it eats, and store them in its appendages, also known as cerata. This process is called kleptoplasty, and it enables “Shaun” to harvest/feed of the energy that is released by the photosynthesis of these accumulated chloroplasts . Pretty clever way to go about it, as you’re never really sure when the next meal will be!
In this clip we see that the life of a superstar is far from easy. Since they usually live in shallow waters, there is a real chance that water conditions, like waves, currents, or surge, might quite literally throw them of their game …
Take a Minute to Relax VII
In this episode of visual meditation, we take you for a minute long swim over a healthy reef, with an abundance in marine life. Coral reefs make up less than 1% of the ocean's floor, yet are home to more than 25% of all marine life. The oceans depend on healthy coral reefs for its inhabitants, but so do we ... Coral reefs protect the land above the surface from the full force of the oceans. So, by protecting the reefs, we are in fact protecting ourselves! Enjoy the energy of a healthy reef, and the feeling of weightlessness ...
Take a Minute to Relax VIII
The setting of this episode of visual meditation, is the Liberty Wreck in Bali. Here on a cloudy day in February, a Hawksbill Turtle (Eretmochelys imbricata) indifferently passes by, in search of food. She has learned over time that divers pose no threat to her, and comfortably swims around. Unfortunately, like all other sea turtles, the Hawksbill is an endangered species. Many of them drown when stuck in ghost nets, or other plastic rubbish. Although increased boat traffic, as well as human encroachment on their nesting beaches, aren't helping much either...
The Hawksbill is rather aptly named, since it has a very pronounced beak resembling that of the bird of prey. An easy way to distinguish between the sexes, is the size of their "tail". When it's large it's a male, and when it's short it's a female. In this (butt)shot, it's quite easy to determine the sex of this particular Hawksbill. On top of that, during these complicated times it's nice to watch a sea turtle's butt for a while! 🙂
Take a Minute to Relax IX
In this episode of underwater meditation, we would like to introduce you to a creature whose scientific name does it much more justice than the common names it goes by. Known by divers and snorkellers as a Seamoth, Pegasus, or Dragonfish, its scientific name has it all: Eurypegasus draconis. The Greek word "eury" meaning long, "pegasus" after the legendary winged horse, and the Latin word "draconis" meaning dragon. This beautiful little critter is an ancient relative of the seahorse, and it too has an exoskeleton made of interlocking bony plates. They're actually able to change the colour of their suit of armour to better blend into their environment. Interestingly, unlike many other fish, this creature sheds its scales all in one go, leaving a cast much like a snake or crustacean. This is done as often as every 5 days, and is believed to be linked to achieving the perfect camouflage for this bottom-dwelling fish.
It has a short squat body with a tail roughly the size of its upper body. It also possesses beautiful wing-like pectoral fins, which it uses to crawl along the seafloor with. Although, when one looks closer, one can see that it also has 2 adapted anal fins that are the main contributing source of its movement. Another distinguishing feature is its long rostrum, or snout, with which it can dig in the sand to find food. The mouth of this creature is actually underneath the rostrum, rather than on the tip of it.
Eurypegasus draconis mate for life, and can therefore often be found roaming the seabed together. Unlike its distant relative the seahorse, they are broadcast spawners. This means they glide up to about 50cm of the bottom in a dance like display, with their undersides pressed closely together, to release their eggs and sperm in the water column where they can mix freely before drifting away. It is the weird and wonderful creatures, like the Eurypegasus draconis, that make diving, and in fact life itself, such an interesting experience!
Take a Minute to Relax X
In this 10th episode of visual meditation, we'd like to introduce you to the elegant squat lobster (Allogalathea elegans). This curious creature is actually closer related to hermit crabs than to lobsters, as the name might suggest. It lives in a symbiotic relationship with crinoids (featherstars), and are therefore also known as Crinoid Squat Lobsters.
Crinoids themselves are often mistaken by divers and snorkellers as being a plant. They are in fact animals classified as "Echinoderms", members of the phylum Echinodermata, which roughly translated means "spiny skin", and includes seastars, sea cucumbers, and sea urchins. The elegant squat lobsters find protection from predators in the arms of the crinoid. They can live without the crinoid, however, its life expectancy would be a lot shorter.
So, understandably they like to stay with their hosts. To further increase their chances of survival, they adapt their colour to that of their hosts, making it even harder for potential predators to spot them. The elegant squad lobster, as well as its host the crinoid, both feed on the same plankton diet. Another great benefit for the squat lobster, since its host will always try to find the best place possible to catch food in the passing currents.
Females are larger than their male counterparts and can grow to about 2.5 cm. This gorgeous little creature can be found in the warm waters of the Indo-Pacific region, including the Red Sea. So, good luck finding them next time you're in the ocean!
Take a Minute to Relax XI
In this episode of visual meditation, we invite you to fly with us over a beautiful coral reef. As mentioned before in “Take a Minute VII”, healthy coral reefs play a vital role in the overall condition of the oceans at large. However, senseless destruction, fuelled by ignorance and greed, has left the majority of reefs worldwide dead or dying.
Fortunately, there are some that have understood the value of coral reefs and have started projects to protect them. But protecting the reefs is difficult without the support of the local communities. Many of the richest reef systems on this planet are located in regions where people are most dependent on the ocean and reefs for their food. Unlike the fishing industry, these people are not so much fishing for profit, as they are for survival.
It is therefore not an easy task to start a conservation project and to make it understood to the local population that it would be in their best interest to participate. After all, most of the time there are no immediate results for them to profit from. Understanding that inhabitants of a region have to profit more directly from such conservation efforts, has led Lorenz Mäder (owner/founder of Wakatobi Dive Resort), together with the population of Tomia and Lintea islands in the region of Wakatobi, to come up with the “Collaborative Reef Protection Program”.
With this program, the resort basically leases the use of the reefs of the local villages, and pays them fees/financial aid, under the condition that destructive fishing practices are no longer permitted. Restrictions on how and where one can fish, as well as agreements on particular “No Take” zones, are also included in this program. To make sure these agreements are adhered to, the reefs are “patrolled” by the boats of the resort, as well as by boats from the local communities (Patroli).
The program doesn’t end there. Besides the sustainable income to the local villages in the form of these “lease” fees, Wakatobi Dive Resort also provides electricity, helps with education projects, provides infrastructure, supplies the local hospital with necessities when needed, but most importantly the resort provides over 200 local people with a job! This is a place where jobs are hard to find, or come by. This program has led to a sort of mutually beneficial symbiosis (Mutualism) between the Wakatobi Dive Resort and the surrounding villages on Tomia and Lintea, whereby both profit from this “Collaborative Reef Protection Program”.
For the people of the region, there’s a steady sustainable income, as well as the before mentioned benefits. But because of the reef protection efforts, there is an increasing amount of fish, and in larger sizes. This means that it has become much easier for the population to catch the fish needed to support their families. All of this has led to a higher standard of living for the villagers on these islands and made the people believe that conservation is more profitable than destruction.
On the other hand, the resort benefits from this arrangement as well. The reefs around Tomia and Lintea, as well as the Sawa reef system, are a sight to behold! Kilometre after kilometre of unspoiled reefs with a mind-blowing abundance of marine life. That combined with an impeccable service, Wakatobi Dive Resort draws in people from all over the world. And even though the resort can most definitely not be described as a budget destination, the number of repeat guests is very high. Which is of course great news for all that are a part of this “symbiosis”.
But the resort takes its conservation efforts a step further. Apart from installing/maintaining moorings for their dive operations, as well as regular reef monitoring and cleaning when needed, the resort also treats its wastewater in biological ways, to prevent nutrients from entering the ocean. But most of all, and this is something that is often overlooked in other dive operations, it implements strict rules to minimise diver impact. All guests have to agree to the resort’s dive conduct regulations during their diving activities, and failure to comply can lead to exclusion from diving without a refund. In our opinion, this is a vital step in reef conservation, because the dive industry is responsible for a large part in the destruction of reefs worldwide, through its unregulated tourism.
The “Collaborative Reef Protection Program” has been a great success, and now has over 30 km of reef under its protection. The reef systems around Wakatobi Dive Resort are one of the few places in the world where the quality and diversity of the reefs, that are already stunning, are actually getting better by the year! A great example of how conservation can, and perhaps should be done, on a larger scale. After all, conservation is only possible if everybody profits from it.
Take a Minute to Relax XII
In this episode of underwater meditation, we would like to introduce you to "Bryaninops natans". These members of the large family of Gobiidae, are better known as the "Hovering -, or Pink Eye Gobies". This rather aptly named creature can grow to a maximum size of around 2,5 cm, and seem to prefer living in Acropora hard corals, that offer them some shelter from predators. They can be found hovering above these corals in groups, as they dart backwards and forwards to catch their food in the passing currents.
These small fish are fairly widely spread throughout the tropical waters of the Indo-Pacific and have even been found in the Red Sea. These interesting gobies have translucent bodies, not just as juveniles but for their entire lives! It is therefore only natural to see this remarkable feature is rewarded with some bright yellow insides, which really compliments the colour of their eyes. 🙂
Nature can be so entertaining. Studies have shown, that Pink Eye Gobies are not suffering from conjunctivitis, as was previously suspected. As it turns out, when most of one's body is transparent, one resorts to some drastic measures with the few remaining visible parts one has left. In the end, it's all about creating the right look ...
Take a Minute to Relax XIII
A very warm welcome to another session of "Take a Minute" to relax. Dive right into our visual meditation and watch this adorable creature in all its glory for one minute. Hummingbird bobtail squids, also known as Berry's bobtail squids (Euprymna berry) grow only up to 3 cm (male) and 5 cm (female). During the day they stay buried in the ground and come out to hunt at night.
Bobtail squids have 2 tentacles and 8 suckered arms and also possess a special light organ, where bioluminescent bacteria lives in a symbiotic relationship. Fed by sugar and amino acids, they hide the silhouette of the squid when viewed from below by matching the amount of light hitting the top of the mantle. Counter-illumination is one of the methods of camouflage used in the animal kingdom.
In the case of the little guy (maybe 2.5 cm), it didn't keep those pesky divers away and so it buried itself again. Please, never stress them by forcing them back out again. That's part of reef protection. Respect nature - below and above the surface!
Take a Minute to Relax XIV
In this episode of visual meditation, we'd like to introduce you to the Longhorn Cowfish (Lactoria cornuta). This curious-looking creature has 2 spine-like horns growing from the front of its head, and 2 more from the back of its body. These make it harder for any would-be predator to swallow them. Their body has plate-like scales that are fused together to form a solid box-like carapace and the fins, tail, eyes, and mouth protrude from this. Due to their armour, these fish are slow-moving and rely on their pectoral fins for propulsion.
Cowfish are closely related to Pufferfish, and although they don't have the ability to puff themselves up, they do have a symbiotic relationship with types of toxic bacteria similar to the Pufferfish. These bacteria produce ostracitoxin which is a powerful neurotoxin. The ostracitoxin’s are found in their skin and internal organs. In addition to being poisonous, they have the ability to secrete the ostracitoxins into the water when stressed. This acts as a chemical defence when they are attacked by predators.
To the dismay of many an aquarist who thought this funny looking creature would be a great addition to their tank, when stressed the Longhorn Cowfish is capable of killing every fish in an aquarium, including itself. An unfortunate case of murder-suicide, that once again shows us that creatures should not be imprisoned for our own entertainment.
Take a Minute to Relax XV
In this session of our visual meditation series, we'd like to bring the Trumpetfish, in this case Aulostomus chinesis, to your attention. Their scientific name "Aulostomus" is derived from the Greek words for flute (aulos), and mouth (stoma). Looking at the creature, one can sort of understand how they got to this name. Worldwide there are 3 species of Trumpetfishes, namely A. maculatus which can be found in the Caribbean Sea and Northern parts of South America. A. strigosus, which inhabits the Atlantic coastal waters of Africa and South America. And lastly, the leading actor of this episode, A. chinesis, which lives in the Indo-Pacific region.
Trumpetfish are easily recognizable by their long elongated bodies, and long heads with compressed snouts. At the tip of these elongated snouts, is a single prominent barbell, which can be used for defence. Their dorsal and anal fins are small, reduced, and set very far back on the fish’s body, lending an almost snake-like appearance. Their dorsal fins are preceded by twelve dorsal spines, and the caudal (tail) fin is small and highly rounded. All of these adaptations have led to the fact that the Trumpetfish is not a great swimmer.
They like to inhabit the seagrass beds, coral reefs and reef flats of the tropical and sub-tropical waters in their particular areas, where they can be found in areas with abundant vertical structures, like whip corals, sponges, and fan corals, in which they can easily blend in. From these places of concealment, they hunt for small fish and crustaceans, usually approaching their prey slowly from above, in a vertical manner. They have also been known to use larger fish, or even divers, as camouflage in their search for food. Although most of their food consists of small prey, they have been known to occasionally dine on larger fish as well, like grunts and surgeonfish. When hunting, Trumpetfish are able to open their mouths wider than the diameter of its own body, facilitated by elastic mouth tissues, creating a vacuum that sucks the prey into the fishes mouth.
The intricacies of Trumpetfish reproduction are not well studied, but it is known that they use their chromatophore colour changing abilities to conduct elaborate mating display rituals. These courtship rituals occur near the surface, then, as in their close relatives the seahorses, the burden of caring for the eggs is given to the male, who fertilizes them and carries them in a special pouch until they hatch. What an amazing creature!
Take a Minute to Relax XVI
The guest star in this Minute of visual meditation is the Halimeda ghost pipefish (Solenostomus halimeda). The name of this creature is derived from the Greek words soleno, meaning tube-like, and stoma, meaning mouth. Whereas the word “Halimeda” comes from the green calcareous algae, in which this creature can most often be found.
Although they’re closely related to pipefishes and seahorses of the family Syngnathidae, they differ from Syngnathids in both structure and behaviour. Instead of armoured rings, ghost pipefish are covered with large bony plates. They tend to swim upside down through their preferred habitat, which makes them very difficult to spot. Feeding on tiny crustaceans, especially mysids, which are rapidly sucked in through the long tubular snout, ghost pipefish are ambush predators, that stealthily approach their unsuspecting prey from above, in this head-down position.
Unlike Syngnathids, where the males take care of the fertilised eggs in a special pouch, with Solenostomidea it’s the female who carries the eggs in a brood pouch formed by the fusion of her pelvic fins, which are continuously fanning fresh water over the eggs. Most species of ghost pipefish spent a relatively long period floating around in the ocean as plankton, reaching almost adult length before they finally settle onto the reef. This means that they have a wide geographic range since they can travel long distances after they are born. However, since they only spend the adult/reproductive part of their lives on the reef, it also means that divers have a very short time frame to find this creature in a particular spot before they disappear. This time frame is no doubt made even shorter by the large number of predators inhabiting the reefs.
They're generally found living in pairs with the smaller, skinnier of the two male and the larger individual, with bigger fins the female. The Halimeda ghost pipefish is with its maximum of 7 cm, the smallest of the 6 scientifically recognized species of Solenostomidea. As their name suggests, they’re to be found among Halimeda algae growing on the reef. The head of a Halimeda ghost pipefish is almost equal to the length of the body. Their rounded fins are perfectly resembling the growth segments of the Halimeda algae it prefers to inhabit. The species is highly variable in colour (from bright green or red to white) and is sometimes covered with fine filaments that give the fish a 'hairy' appearance.
A very special little critter that is worth spending some time with. Should one be fortunate enough to come across one ...
Take a Minute to Relax XVII
Our creature of interest in this one-minute episode of visual meditation goes by many names. Squat shrimp, anemone shrimp, dancing shrimp, sexy shrimp, just to name a few. Thor ambionensis has a maximum body length of 13 millimetres. Their base body colour varies from red/orange to light brown, and even green. They have irregular blue/white circular marks on the body. In the centre of these marks, there are yellow lines and dots. On the brown coloured specimens, the colours in the centre of these marks are slightly different.
There are two or sometimes three similar coloured bands around the tail area and the tail fan has similar coloured markings on the top and the bottom. There are three sets of walking legs and a set of legs with small pincers known as chelipeds and a proportionally longer set of feelers. They have a habit of holding their abdomen above their head and wagging the tail giving them one of their common names.
Though it is named after Ambon, or Amboyna Island, one of the Maluku Islands in Indonesia, Thor amboinensis has a pantropical distribution and can be found in the Red Sea, the Indian Ocean, the Pacific Ocean, the Caribbean Sea, the Gulf of Mexico, and even at the Atlantic islands of Madeira and the Canaries. They prefer to live in a symbiotic relationship with anemones, but when none are around, can also be found in certain species of corals.
Living among the tentacles of their preferred host, the voracious anemone offers them a safe home from which they can feed on tentacle tissue, as well as on the mucus-trapped planktonic particles adhering to it.
The female Thor amboinensis carries the fertilised eggs under her abdomen until they are ready to hatch. The zoea larvae pass through several stages and, before undergoing a metamorphosis, are attracted by both chemical and visual cues which cause them to settle near potential host anemones. Researchers found that the larvae of Thor amboinensis were generalists, being attracted by and accepting several different species of anemone as hosts. In some experiments, they had a preference for the species of anemone from which the parent shrimp had been collected.
It’s always fun to spend some time with these little fellows and watch them dance around, shaking that booty.
Take a Minute to Relax XVIII
In this minute of visual meditation, we invite you to glide with a school of round batfish over a beautiful reef in Wakatobi. To avoid confusion with the other batfish of the family Ogcocephalidae, members of the group known as anglerfish, these round batfish are often referred to as spadefish, or platax.
The body of Platax orbicularis is almost disc-shaped, and very thin. Its tail, about 20% of the body length, is fan-shaped and is taller than it is long. Males can grow to up around 50 cm (20 inch) in length. This species has a wide range that extends from the Red Sea, Indian Ocean, all the way to the Pacific Ocean. They have been recorded off the coast of Florida as well, although this is thought to be the result of dumping of aquarium specimens.
These fish can be found singly, in small groups, and occasionally in large schools around reefs and wrecks, at depths ranging from 5-30 meters. Small juveniles are yellowish to reddish-brown and resemble leaves drifting amongst flotsam at the surface or moving along the bottom in the current. Platax orbicularis normally feeds on algae, invertebrates and small fishes, but has been known to spice their diet up at times with the occasional anemone.
What is lesser known, is that this species is a singer! Though their calls are not quite as melodic, as say that of birds, they are certainly diverse. Like with birds, their choruses occur mostly at sunrise or sunset, and sometimes both. Why they perform these serenades is still up for debate, but their songs seem to have a distinct staccato beat to them. Although the acoustic abilities of certain fish species still needs further research, the benefits of it are pretty clear. Singing offers considerable advantages as it means the fish can communicate at night, when predators can’t see them, and due to the density of the water, it allows them to communicate over long distances and bring animals together for spawning events. All species of fish can make sounds, but only some can sing. This evolutionary talent occurs in the‘swim bladder’, a large bubble of gas inside most fish that is used to control their buoyancy. Singing fish can control the muscles of their swim bladder, driving it to create sound. This makes Platax orbicularis an even more interesting creature, than it already was.
Enjoy your swim with these beautiful shiny, silvery, musical fish.
Take a Minute to Relax XIX
In this minute of relaxation, we’d like to focus your attention on a curious-looking sea creature digging in the sand, named the “Moon-headed sidegill slug” (Euselenops luniceps). Euselenops luniceps is a species of sea slug, a pleurobranchomorph gastropod mollusc in the family Pleurobranchaeidae. This family of sea slugs is known as "side-gilled slugs" since they have their gills hidden on the right side of the body under the mantle (the body edge). This slug is perfectly adapted for living in a sandy environment.
In most pleurobranchs, the foot and mantle are of similar size but in Euselenops the foot is much larger, which makes it easier to crawl over sand, or burrowing underneath it. Posterior, the mantle folds into a relatively long siphon or tube, which allows the mantle cavity and gills to remain in contact with fresh seawater while the animal is buried in the sand. With the incoming seawater, the animal can also sense chemical released by potential prey nearby. It has a large oral veil fringed with lots of sensory 'hairs' on the underside to detect prey.
This unique looking creature roams along sandy and silty sea bottoms for food with a very pronounced large oral veil, which underneath is fringed with tiny sensory "hairs" (papillae), to help it detect prey. Although it is a predator, little is known about what it eats. It appears they have a particular fondness for anemones, however, they have also been observed on sand flats at low tide, where they hunt and swallow whole any invertebrates that they touch with their large oral veil.
While most sea slugs move quite slowly, Euselenops with their active food gathering approach can move surprisingly fast. Not only does it have speed, but this slug can also actually swim for some distance by flapping the sides of its body, much in the same way as its more famous cousin, the “Spanish Dancer” (Hexabranchus sanguineus) does. Despite the fact that many websites claim the maximum size of this creature is approximately 7cm, this particular specimen filmed in Amed (Bali), was closer to 20cm.
We hope you’ll enjoy your Minute with this weird and wonderful creature...
Take a Minute to Relax XX
The star of this week’s episode of “Take a Minute” goes by many names, of which "Yellow pygmy goby" is just one. Since the name so perfectly describes this creature, I could’ve probably just left that… Anyway, Lubricogobius exiguus is a member of the family of Gobiidae. This family is tremendously large, comprising of over 2000 species in more than 200 genera, spread over 6 subfamilies. And yet none of them can be considered big. This cute little creature can grow to a maximum size of about 4cm. They prefer to inhabit muddy substrates, usually with rocky outcrops of rubble and/or debris, and can often be found in pairs, living in empty shells, holes, or in between the branches of hard coral, like Acropora, that provide them with a safe place for their eggs, as well as themselves.
Lubricogobius exiguus is one of those species that seems to have made the best of a bad situation, by seeing the ever-increasing amount of man-made rubbish coming into the ocean, as new real estate opportunities! These days, this species can often be found in discarded bottles, cans, and other trash with small openings. They feed on a variety of algae, plankton, and small invertebrates. This particular species of bright yellow fish doesn’t exactly blend into it’s preferred habitat of drabby dark colours. Thereby creating a contrast that seems irresistible to underwater photographers, and “critter enthusiasts” alike.
Take a Minute to Relax XXI
In this minute of relaxation, we invite you to look deep into the eyes of this beautiful creature and let it take you on a journey through time and space. Amphioctopus marginatus, also known as the “coconut octopus” and “veined octopus”, is a medium-sized cephalopod belonging to the genus Amphioctopus. Meeting any octopus is as close as we can currently get to an alien encounter. Their physiology is truly otherworldly!
They have a large brain that extends into the nervous system of their arms! Which means that its brain is not in 1 particular place, as with most other creatures, but has more of a “Multiverse” approach to brain function. Lacking skeletal support, this creature’s arms work as muscular hydrostats and contain longitudinal, transverse and circular muscles around a central axial nerve. Which basically means that they can extend/contract their arms, twist left or right, bend at any place in any direction and/or be held rigid. Each arm has a multitude of muscle controlled suction cups, that can grab, feel, manipulate, and even taste objects. Octopuses are basically “brains with arms”, or “thinking muscles”, that can control their bodies to such an extent, that they’ll fit through any opening the size of their beak. The parrot-like beak of all octopus species contain venomous saliva and is the only hard part of their bodies.
Octopuses, as well as some other cephalopods, are capable of greater RNA editing (which involves changes to the nucleic acid sequence of the primary transcript of RNA molecules) than any other organism. More than 60% of RNA transcripts for their brains are re-coded by editing, compared to less than 1% for that of a human’s. This allows the octopus to evolve/adapt/learn from the experiences of previous generations, without actually being taught.
Octopuses have 3 hearts and depend on the copper-rich protein, haemocyanin, for oxygen transport throughout the body. Although in cold conditions and with low oxygen levels, haemocyanin transports oxygen more efficiently than haemoglobin, it also tends to make the blood thicker, resulting in blood pressures that can exceed 75 mmHg (10 kPa). But, with 3 hearts, the octopus isn’t really worried about high blood pressure. As an added bonus, the haemocyanin makes the octopus’s blood look blue-ish. True royalty!
Named for their use of coconuts as tools for defence, the coconut octopus can also use clamshells, or these days a variety of plastic rubbish, depending on their size. Although they have the ability to burrow and hide in the sand, they prefer the extra security these tools are giving them. Often the shells and husks that the coconut octopus gathers, will be used for dens or “defensive fortresses”.
Amphioctopus marginatus is even capable of bipedal (2 legged) movement and slit-walking, which allows them to carry the coconut or clamshells, with the remaining 6 arms. The octopus will carry a shell with it while searching for another, testing several as it scavenges as a hermit crab might. Coconut octopuses are commonly found throughout the tropical Pacific and the Indian Ocean. Their main body is normally around 8 centimetres (3”) tall and including the arms, approximately 15 centimetres (6”) long.
Their diet includes invertebrates such as shrimp, crabs and clams, although they will also eat small fish if they can catch them. With three to five years the coconut octopus has one of the longer life spans for octopuses. The primary contributing factor to determining their life span is when they decide to mate. The coconut octopus reaches sexual maturity between 18 and 24 months of age. Once a male mates he will die within weeks, sometimes days thereafter. The female will die only after she has laid her eggs and they have hatched.
The mating ritual of the coconut octopus is a “fast and furious” affair. Males prefer to insert their sperm packet with their specialized “sex arm” into the mantle of the female as quickly as possible. It has been observed in the wild that the females often strangle the males that hang around too long, and then eat them. Not quite the preferred dinner date ... To avoid being eaten, male coconut octopuses employ the “mate and dash” technique. Some also disguise themselves as females in order to stand a chance while approaching.
Since the mating style of the coconut octopus is designed to be as fast and as distant as possible, there have been observations of a female octopus “entertaining” two or more male suitors at once. Yes, a saucy coconut octopus underwater orgy, so to say. Since the female carries the sperm packets in her mantle until she is ready to lay her eggs, having sperm packets from multiple males is not a problem. Consequently, the hatchlings that emerge from a specific brood can have multiple fathers. What a fascinating alien creature this octopus is!
Take a Minute to Relax XXII
In this episode of underwater relaxation, we would like to introduce you to this beautiful little Xmas creature that is dressed for the occasion. Primovula roseomaculata, also known as a Soft coral cowrie, Allied Cowrie, or False Cowrie, is a species of sea snail, a marine gastropod mollusc in the family Ovulidae.
Molluscs are a big and very diverse group of creatures consisting of animals as different as mussels and octopuses! Most colourful and strikingly patterned among the molluscs are the cowries. Their shells were used as currency in different cultures throughout history and are now prized collector items, due to their shining and often brightly coloured and patterned shell.
However, what we as ocean enthusiasts see, is not the shell itself, but rather the soft mantle of the animal, wrapped around the shell. The mantle is even more beautiful than the shell itself, often bearing a striking resemblance to the soft coral that these cowries prey on, even including tentacle-like protrusions, to completely blend in with its coral host. These branching papillae on their mantle are not only there to complete the finishing touch on their extravagant camouflage, but assist in the respiration of the cowrie as well.
Primovula roseomaculata usually live and feed on soft corals of the genus Dendronephtya. Due to the potent toxins used by these corals to deter predators, these cowries have adapted to only a single coral species. This behaviour has led to the rise of one of their common names, the “Allied Cowrie”. However, “Allied cowries” are in fact parasites, that harm their hosts. They feed on the coral’s tissues, mucus and polyps, and are able to absorb the pigments of their coral host, which enables these cowries to match their host's colour so well. Not only that, but Primovula roseomaculata has the ability to even extract the defensive chemicals of the coral host, and store them in the skin of its own mantle, where they can protect the snail from fish predation! The host coral will continually regrow the lost tissue, so the cowrie never runs out of food, and or ammo!
They start off their lives as free-swimming post-larval juveniles and probably detect chemical clues that signal a potential host is nearby. Hosts are often home to several individuals. When settled, cowries graze up and down the coral and eventually deposit their eggs on a bare branch, beginning the cycle all over again.
Take a Minute to Relax XXIII
In this first minute of relaxation of the new year, we’d like to focus your attention on this gorgeous, but voracious little hunter. A juvenile Harlequin Shrimp. There are two types of harlequin shrimp. Hymenocera elegans, is native to the Indo-Pacific region, and hymenocera picta, which is specific to Hawaii. The name of the genus Hymenocera is derived from the Greek words “hymen” (membrane) and “keras” (horn, or in this case antennae), indicating that this crustacean has lamina-shaped antennae. Whereas both “elegans”, as well as “picta” refer to the beautiful coloured spots adorning the exoskeleton of this decapod.
They are reef dwellers, preferring water temperatures of 24-29 degrees Celcius, and are especially partial to a habitat with spaces for them to retreat into, like branched corals or rock formations. Their eyes are positioned on stalks, and they have two giant flat claws that serve as snipping tools while harvesting their prey. Females are generally larger than males and can grow up to around 5cm.
Harlequin shrimp are white to light pink in colour, with splashes of bright coloured spots on their entire body, usually red, purple, orange, and blue. Despite their relatively small size, they have few natural predators. This is thanks to their markings and colouration. Like on land, in the ocean bright patterns are a red flag to predators of toxicity. In addition, their colouration serves as a wonderful camouflage when moving along a coral reef, mimicking the bright lights and shadows produced by the overhead sun.
What’s curious about the Hymenocera is that they live almost exclusively on a diet of sea stars. Some have been observed munching on sea urchins, but generally speaking, sea stars are their comfort food. The harlequin shrimp has two flat antennae that are used for detecting the scent of sea star prey. They will often hunt as mating pairs, and work together to overtake and devour their prey. One shrimp will use its claws to clip the soft tube feet attaching the sea star to its surface, while the other then pulls the creature away from the surface and onto its back.
Some harlequin shrimp will then drag the sea star to its lair, and feed on its tube feet and soft tissues. Unable to right itself, the starfish will then endure being eaten alive for a period of days to weeks, depending on the size of the starfish. Harlequin shrimp have been observed feeding the starfish to keep it alive for their consumption.
Harlequin shrimp mate for life, and are fiercely protective of their family territory. Once the pair finds a suitable home within the reef, they are known to stay within the area for months or even years. The pair mate after the female moulds, and can produce anywhere from 100 to 5,000 eggs per breeding season. This may seem like a lot of offspring, but the high demand for harlequin shrimp in the aquarium trade has made them rarer in the wild.
Since Hymenocera has a symbiotic relation with corals, this isn’t exactly good news for coral reefs! Hymenocera preys on sea stars that would otherwise eat the corals, and in return for its efforts, it gets a safe place to live. Without the help of these little creatures, the future of the reef as a whole is at risk.
Take a Minute to Relax XXIV
In this Minute of tranquillity, we’d like to introduce you to one of the ocean’s most recognisable icons, the reef manta ray. The species was described in 1868 by Gerard Krefft, the director of the Australian Museum. He named it M. alfredi in honour of Alfred, Duke of Edinburgh, the first member of the British royal family to visit Australia. It was originally described as part of the genus Manta but in 2017 was changed, along with the other manta species, to be included as part of the genus Mobula. The artist formerly known as Manta alfredi, is as famous, as it is graceful. This gentle giant is the smaller of the two manta species currently known to science.
Despite their distinctive flattened body, this fish is closely related to sharks. At the front, it has a pair of cephalic fins which are forward extensions of the pectoral fins. These can be rolled up in a spiral for swimming or can be flared out to channel water into the large, forward-pointing, rectangular mouth when the animal is feeding. The eyes and the spiracles are on the side of the head behind the cephalic fins, and the five gill slits are on the ventral (under) surface. It has a small dorsal fin and the tail is long and whip-like. The manta ray does not have a spiny tail as do their close relatives, the devil rays (Mobula spp.). The colour of the dorsal side is dark black to midnight blue with scattered whitish and greyish areas on the top head. The ventral surface is white, sometimes with dark spots and blotches. The markings can often be used to recognise individual fish. Mobula alfredi is similar in appearance to Mobula birostris and the two species may be confused as their distribution overlaps. However, there are distinguishing features.
The first difference is the size. M. birostris is bigger than the reef M. alfredi, 4 to 6 m on average vs. 3 to 4 m. However, when they’re young specimens telling them apart becomes somewhat difficult, in which case only the colour pattern remains an effective way to distinguish them. The reef manta has a dark dorsal side with usually two lighter areas on top of the head, looking like a nuanced gradient of its dark dominating back colouration and whitish to greyish, the longitudinal separation between these two lighter areas forms a kind of “Y”. While for the oceanic manta, the dorsal surface is deep dark and the two white areas are well marked without gradient effect. Meanwhile, the line of separation between these two white areas forms a "T". Also, the reef manta ray has a white belly with often spots between the branchial gill slits and other spots spread across trailing edge of pectoral fins and abdominal region. The oceanic manta has also a white ventral colouration with spots clustered around lower region of its abdomen. Its cephalic fins, inside of its mouth and its gill slits are often black.
Both species have the largest brain of all know fish species and are very curious and intelligent. Because of its large size and velocity in case of danger (24 km/h escape speed), the reef manta has very few natural predators which can be fatal to it, apart from some large shark species and orcas. Since there’s so much to tell about this beautiful creature, more info will follow in future Manta Minutes …
Take a Minute to Relax XXV
In this session of tranquillity, we would like you to focus on the living art that is the coral reef and its protection. This particular reef, named Fan 38, is located at Wakatobi Dive Resort and is one of our favourite reefs on this beautiful Blue Planet. Reef-building corals consist of colonies of tiny animals, all sharing the same genes. In other words, any particular hard coral is one creature, as well as many creatures at the same time … When the conditions are just right, these animals can grow prolifically, albeit at a very slow pace, creating the cathedral-like structures we love so much.
These days, pretty much all of the coral reefs worldwide are under threat. Luckily, some localized conservation efforts are paying off, and allow the reefs there to recover. Coral reefs are pretty much a symbiotic organism in itself, depending on all the lifeforms that inhabit them, as well as those that visit temporarily, for survival. A technique that is used by pretty much everything in the natural world. Everything is connected …
Therefore, every action is affecting everything else. So, in nature there is no good or bad, there are only consequences. Unfortunately, our species seem to have forgotten this fact. Which is somewhat strange, since we ourselves are also symbiotic creatures of sorts, who depend not only on the world around us for sustenance, but on the amount and health, of all the bacteria, viruses, and other life forms that share our bodies with us. Take one away, or let another grow out of control, and we get sick as a result.
Same goes for coral reefs, which makes protection and conservation rather difficult, when dealing with a species like ourselves, temporarily claiming dominance over this planet, whilst being conditioned to forget about life’s equilibrium and focus on a fictitious monetary and power system instead. But try as we might, we can not change the fact that we are indivisibly linked to the world around us …
Many of the current reef conservation efforts around the world, like the one in Wakatobi, are private initiatives funded by NGO’s and/or tourism, and as such they’ve had a very difficult time over the last year. There are many people that believe that 2020 has been a good year for nature, and the planet as a whole, due to lockdowns and travel restrictions, but this is certainly not the case for the world’s oceans. Less supervision in protected areas has led to an increase in fishing activities there.
As the world is hopefully opening up again somewhat this year, these conservation efforts are in need of your assistance. Our advice would be to look at the projects one can support when deciding their next holiday destination. Luckily for Fan 38, as well as the many other spectacular coral reefs in the region, Wakatobi Dive Resort has kept a skeleton crew on site, that together with the local authorities, has patrolled and protected the reefs that are part of their conservation efforts. So that when the first guests return to the resort, underwater paradise awaits them!
Take a Minute XXVI: Solar Powered Melibe (Melibe engeli)
In this Minute of Relaxation, we would like to introduce you to one of the most interesting species of Nudibranch, named Melibe engeli. Nudibranchs are molluscs in the class Gastropoda, which includes snails, slugs, and sea hares. Many gastropods have a shell. Nudibranchs have a shell in their larval stage, but it disappears in the process of becoming an adult.
Nudibranchs can thrive nearly everywhere, from shallow, temperate, and tropic reefs to Antarctica and even hydrothermal vents. At present, there are well over 3000 species of nudibranchs known to science, but new species are still being discovered. They come in all shapes and sizes, not to mention wild colour pattern variations, which makes them so popular with divers and snorkellers. The word nudibranch comes from the Latin word nudus (naked) and Greek branchiae (gills), which refers to the gill-like appendages which protrude from the backs of many nudibranchs.
Although they possess eyes, their eyesight is thought to be limited to picking up only light and dark shapes. They view the world through chemical receptors in the shape of tentacles on their heads. These tentacles are called rhinophores and they allow nudibranchs to smell food, find potential mates, predators and provides them with some sort of situational awareness.
However strange it may seem, this colourful family of sea slugs are carnivores, whose prey consists of sponges, coral, anemones, hydroids, barnacles, fish eggs, sea slugs, and other nudibranchs. To eat their food, most nudibranchs possess a radula, which is a toothed structure that they use to “chew” their food up. Some species suck out their prey after predigesting their tissue with selected enzymes, rather like a spider. Nudibranchs are very picky about what they eat, individual species or families of nudibranchs may eat only one kind of prey. Nudibranchs get their vivid colours from the food they eat, which in turn advertises to would-be predators, that they are poisonous, or at the very least foul-tasting. In any case, enough to be left alone by most.
With so many vibrantly coloured and interesting family members, what makes the Melibe engeli stand out? It’s not its size, this creature grows up to around 5cm. And this Melibe doesn’t have any bright colour patterns. But where its carnivorous cousins are going mostly after static prey, this particular species of Melibe is an active hunter, feeding on shrimps, crabs and other small crustacea which they catch by throwing the inflated oral hood over the substrate like a fisherman casting his net. This active “fishing” practice is a joy to observe. However, they lack a radula, which means that their swallowed prey remains alive in the gut until killed by digestive juices.
But what makes this creature even more special, is that it doesn’t rely only on catching its prey for sustenance, it also hosts algae farms in its tissues, that through photosynthesis produce nutrients for the Melibe in situations when food is scarce. The mutualistic symbiosis between different species of nudibranchs and unicellular photosynthetic dinoflagellates of the genus Symbiodinium (often known as ‘zooxanthellae’) has been known to science for quite some time.
Most “solar-powered” nudibranch species take up Symbiodinium from their prey of soft or hard corals and cultivate them inside the cells of their digestive glands. But since Melibe engeli feeds exclusively on small crustaceans, science is still baffled as to how this nudibranch picks up the symbiont zooxanthellae for its emergency solar farms. What a beautiful world we live in, and how fortunate we are to be able to observe all these different adaptations to life on it!
Take a Minute XXVII: Bigeye Trevally (Caranx sexfasciatus)
In this episode of underwater relaxation, we would like to become a part of this immense living silver cloud, and simply go with the flow: Bigeye trevally (Caranx sexfasciatus).
A school of fish this size can literally block out the sun. These Bigeye trevallies (Caranx sexfasciatus) have come together in impressive numbers, to cruise over this beautiful sunlit reef. Bigeye trevallies are currently classified within the genus Caranx, one of the groups known as Jacks or Trevallies. This genus itself is part of the larger mackerel family Carangidae. It’s specific epithet (the second part of the scientific name), roughly translates to “six banded”, and refers to the creature’s juvenile colouration. This species of trevally is rather easily identified due to its big eyes, and are one of the most widespread species of them all.
They can be found in massive schools in the tropical waters from the western shores of Central America, all the way to the east of Africa. Actually, the only place they can’t be found is in the Atlantic Ocean. Bigeye trevally normally live close to shore, down to a depth of around 150 metres. However, they do venture out to make offshore seamounts their home as well. They can even make their way upriver into freshwater. As they reach their adult size of about 80 cm, they can easily weigh 10kg.
Caranx sexfasciatus is a voracious predator that relies predominantly on its speed to overpower and surprise its prey. Their diet consists of other fish and crustaceans, which are mainly caught at night. During the day they like to come together to relax. After all, many big eyes see more than one, and in the ocean one always needs to keep an eye out for a bigger fish. This gives them the chance to visit cleaning stations and enjoy their Spa treatment to the fullest extend. An interesting side note about this creature is that although they usually appear silvery and shiny, like many other species of fish they are capable of changing their colour, all the way to a dark black. It is thought that this capability to change colour is helping them to communicate more efficiently amongst themselves, as well as with other species.
Although Caranx sexfasciatus is quite a common sight around the tropical waters of this planet, it is clearly not a boring creature. And when they come together in large numbers, they’re a sight to behold. Not only taking the light but also one’s breath away.
Take a Minute XXIX: Nudibranchs
In this minute of visual meditation, we would like to focus on nudibranchs in general instead of going into the specifics of the two species filmed in the waters of Bali (Indonesia). Divers lovingly call them nudis, short for nudibranchs, which makes them even cuter and brings out their true nature: beautiful, colourful, and exotic on the one hand, mysterious, bizarre and toxic on the other.
Different families of nudibranchs (further split into genus and species) form the order Nudibranchia within the large taxonomic class Gastropoda, commonly known as snails and slugs. While all nudibranchs are sea slugs, not all sea slugs are nudibranchs. The name nudibranch originates from the Latin „nudus“, meaning „naked“, and the Ancient Greek βράγχια (bránkhia) for „gills“, referring to the gill-like appendages which protrude from the backs of many nudibranchs.
Although they possess eyes, their eyesight is thought to be limited to picking up light and dark shapes only. They view the world through chemical receptors in the shape of tentacles on their heads. These tentacles are called rhinophores and they allow nudibranchs to smell food, find potential mates, predators and provides them with some sort of situational awareness.
Nudibranchs can thrive nearly everywhere, from shallow, temperate, and tropic reefs to Antarctica and even hydrothermal vents. At present, there are well over 3,000 species of nudibranchs known to science, but new species are still found. Discoveries of large numbers of bioactive compounds suggest that sea slugs are an excellent biomedicine source which has fueled the research into this order within the animal kingdom.
However strange it may seem, these colourful families of sea slugs are carnivores, whose prey consists of sponges, coral, anemones, hydroids, barnacles, fish eggs, sea slugs, and other nudibranchs. To eat their food, most nudibranchs possess a radula, which is a toothed structure that they use to “chew” their food up. Some species suck out their prey after predigesting their tissue with selected enzymes, rather like a spider. Nudibranchs are very picky about what they eat, individual species or families of nudibranchs may eat only one kind of prey. Nudibranchs get their vivid colours from the food they eat, which in turn advertises to would-be predators, that they are poisonous, or at the very least foul-tasting. In any case, enough to be left alone by most.
The characteristic of aeolid nudibranchs, like the ones in this clip, are long, narrow bodies with numerous horn-like extension which are called cerata and serve as gills. The form of the cerata extends the surface for respiration significantly and is also used for defence. Various species feed on hydroids and their stinging cells (nematocysts) pass through the digestive system of some aeolids and are build into the tips of their cerata (watch “Take a Minute II” for more details).
Nudibranchs have a shell in their larval stage, but it disappears in the process of becoming an adult. They come in all shapes and sizes, not to mention wild colour pattern variations, which makes them so popular with divers and snorkellers. Some are very hard to tell apart, others strikingly different from anything you have ever seen before. Some stand out, others are highly camouflaged.
They also vary in sizes from massive beasts such as the“Moon-headed sidegill slug” (Euselenops luniceps) presented in „Take a Minute XIX“ to tiny speaks of some millimetres, like Costasiella kuroshimae a.k.a. “Shaun the Sheep” (shown in „Take a Minute VI“). This tiny creature has the ability to extract the chloroplasts from the food it eats and stores them in its cerata. This process is called kleptoplasty, and it enables “Shaun” to harvest/feed the energy that is released by the photosynthesis of these accumulated chloroplasts.
This is also the second feeding strategy of Melibe engeli („Take a Minute XXVI“). Through photosynthesis, the algae farms in its tissues produce nutrients for the Melibe in situations when food is scarce. The mutualistic symbiosis between different species of nudibranchs and unicellular photosynthetic dinoflagellates of the genus Symbiodinium (often known as ‘zooxanthellae’) has been known to science for quite some time. Most “solar-powered” nudibranch species take up Symbiodinium from their prey of soft or hard corals and cultivate them inside the cells of their digestive glands. But since Melibe engeli feeds exclusively on small crustaceans, science is still baffled as to how this nudibranch picks up the symbiont zooxanthellae for its emergency solar farms.
The search is on - not only for divers and snorkelers.
Take a Minute XXX: Cephalopods
Cephalopods are molluscs with their arms attached to their head. The word is based on old Greek (kephalópodes; „head-feet“). Octopus, cuttlefish and squid are in a class of their own in multiple ways. Classified as cephalopods they lack a backbone in their soft bodies but show remarkable intelligence for invertebrates. These savvy softies arouse a great deal of interest in divers and science alike.
Probably the most fascinating aspect of cephalopods is their ability to change colour as well as the texture of their skin in a blink of an eye. This way they can blend in with their surroundings perfectly. Alternatively, they show bright warning or hypnotizing patterns at will. Just below the surface of their skin sit thousands and thousands of chromatophores (colour-changing cells). Each chromatophore contains a sack of a particular pigment (black, brown, orange, red or yellow). By stretching the sack, the colour appears brighter. A complex system of nerves and muscles controls this magical transformation including the texture of the skin from smooth via small bumps to high spikes.
Additionally, some cephalopods have iridophores, plates reflecting greens, blues, silvers and golds, while leucophores mirror the colour of the surroundings to perfect their camouflage. They use their skill to hide from predators as well as to sneak up on their prey. But colour patterns are also a way to communicate to another or others in the form of flashing bright warning colouration, like the poisonous and venomous Flamboyant cuttlefish. As a last resort, they can release a cloud of ink and disappear through any hole their bony beak fits through. That’s the only hard part of the body of these curious creatures.
Cephalopods have the largest brain-to-body mass ratio as well as the most complex nervous system among all invertebrates. Basically, science is still struggling to understand and test certain aspects of the intelligence of cephalopods. Maybe soon there are new ways to measure and validate other forms of their intelligence too.
Almost all cephalopods are active hunters, pushing them to develop certain strategies and behaviour to find and catch their prey. Some crabs, the base of the most octopus food source, have powerful pincers to defend themselves and a long pursuit costs energy.
Hence, octopuses are looking at how to use the work of others to their advantage, such as stealing bait from lobster traps or climb on board fishing boats to feast on the dead or dying crabs in containers. As described above, cephalopods can use skin colouration and texture to communicate. Posture and locomotion add to their display.
We were lucky enough to observe flamboyant cuttlefish flashing colours in courtship in Komodo ourselves (Flamboyant cuttlefish: King of critters). Eventually, the bigger female stopped and raised her arms to allow the small male to deliver its sperm. They went on for various rounds.
Especially, squid use colour and (flashing) patterns to communicate, not only in courtship (Squids: Upside down and fast backwards). Caribbean reef squid can send different colour patterns to squids on either side of their bodies at the same time. Humboldt squid use communication even in cooperative hunting techniques. Octopuses can be trained to distinguish between different shapes and patterns. In laboratories, they benefit from an enriched environment, using bottles or toys to play with. Furthermore, they have repeatedly shown the ability to use tools. As seen by many divers, they collect, carry and use coconut husks and shells for protecting their soft bodies from predators. The ocean is full of wondrous life forms, that makes us re-think everything we thought we knew about this planet and our place in it!
Take a Minute XXXI: Coral reef life or breathing to relax body and mind
This time in "Take a Minute to Relax" we present coral reef life in the shallows (Wakatobi, Sulawesi, Indonesia). As we have been writing about "The reefs of Wakatobi" in episode XI and "Coral Reef Protection" in episode XXV of our series, we focus on breathing now. After all, it is a minute to relax.
We as humans don’t need to think about breathing, we even continue to breathe when we are unconscious (involuntary breathers). Dolphins, on the other hand, are voluntary breathers, meaning they have to decide when to take a breath. Becoming aware of how we breathe and how breathing is connecting our body and mind is useful not only while diving.
Our breath is controlled by the respiratory centre of the brain. Automatically, we don’t need to do anything – but we can. When we feel stressed, our breathing pattern and rate change, also automatically as part of the evolutionary “fight-or-flight response”. We are taking shallow and rapid breaths into the chest rather than all the way into our bellies. That’s a natural response to be ready and alert.
It can, however, increase the level of stress if we start to feel uncomfortable with this breathing pattern itself or have the feeling of not getting enough air. All too often this process happens without us even recognising the connection to breathing, after all, there’s something else on our mind at that moment.
At a time like that, body functions such as the response of the immune system or digestion, are having a lower priority. So, not a healthy state to be in for very long. We all have been overwhelmed by situations and emotions one way or another. Madly crying, highly agitated or simply furious, all have an impact on our breathing. Maybe somebody told us to “take a deep breath” or “just breath slowly” and hopefully you noticed that focusing on breathing in and out deeply and slowly, actually calms you down.
The connection between body and mind works both ways. As soon as we start to change our breathing pattern consciously, we signal the brain that we have the situation under control, resulting in feeling less stressed. Be kind and be patient. Quickly and forcefully changing your own breathing pattern can lead to disruption, rather than the desired correction. Being able to lift yourself up is definitely worth working on.
Breathing plays an important role in many relaxation techniques from yoga and meditation to mindfulness and other stress relief techniques and, of course, diving. Note: For some people focusing on the breath is actually having the opposite effect (enhancing anxiety levels and panic). If somebody doesn’t feel right underwater, it is the number one thing to do: Eye contact and making sure the breathing is under control. The easiest and most effective way is breathing together, deeply and slowly to get calm and relaxed.
Place your hand in front of your regulator and move it away for exhaling and back towards the face for inhaling. If needed, signal slow/calm down by moving the flat hand (horizontal) up and down. Of course, breathing dry compressed air of a limited supply adds to the pressure to get the breathing under control. But what works underwater works also on land, where you can talk or count out loud for a rhythm. In Open Water diving courses or any sort of try dives, you’ll often hear "breath deeply in and out" or "breath normally".
But what is normal? In fact, we all breathe differently and our normal might not be the desired relaxed state the instructor is talking about. Deeply and slowly might even feel awkward and unnatural – in the beginning. Don’t worry. Most things feel awkward the first time. The more we practise the better we get and all of a sudden we can’t even remember what was the problem in the first place. For starters, we look at ways to breathe.
A good way to start is to actually get to know the different ways to breathe – on land. Lay down or sit comfortably with one hand on your chest and one hand on your belly. Just breathe in and out. Where do you feel a movement? There are two major ways to breathe: Using the diaphragm, a sheet of muscle underneath the lungs, or the muscles between the ribs. When breathing only into the chest, we are not using our full lung capacity. Subconsciously we might have trained ourselves to breathe only with the chest as flat bellies are considered to be more attractive. You can breathe with the diaphragm without moving the belly, but for full abdominal breathing, also known as belly breathing, the belly expands (partially) with the inhalation and contracts with the exhalation. We have a detailed description of how to experience the different areas of the lungs and how to train the full power of breathing (Why breathing is your superpower).
Take a Minute XXXII: Randall’s Shrimp Goby (Amblyeleotris randalli)
After a long wait, we’re very happy to finally bring you another episode of our “Take a Minute to Relax” series. The guest star in it is both flamboyant as well as interesting and goes by the scientific name Amblyeleotris randalli. In the common tongue, there are numerous names for this beautiful creature. Gold-barred Shrimp Goby, Gudgeon, Orangestripe Prawn Goby, Orangestripe Watchman Goby, Randall's Shrimp Goby, Sailfin Shrimp Goby, just to name a few.
Amblyeleotris randalli is a relatively small fish that can grow to about 12cm/4,7”, and can be found in the Western Pacific region. It is part of the Family Gobiidae (Gobies), which is the largest family of marine fishes on the planet, containing nearly 2000 species, possibly even more. One would think that in a family of that size, it’s near impossible to stand out. However, about 120 species of this family have developed a remarkable evolutionary trait, that did just that!
These select few started a mutualistic symbiosis with a completely different creature, namely shrimps of the family Alpheidae. These shrimps are characterized by having asymmetrical claws, the larger of which is typically capable of producing a loud snapping sound, which creates a cavitation bubble that is loud enough to stun their prey. It, therefore, comes as no surprise that these creatures are also commonly known as snapping shrimp, or pistol shrimp. The Alpheid shrimps are incredible diggers, and are constantly creating, and maintaining burrows in the seabed which provides them with a relatively safe place to live.
However, due to their very poor vision, the shrimps are extremely vulnerable to predators every time they dump sand, and/or gravel, outside of their burrow. And this is where the shrimp/partner gobies come in. Amblyeleotris randalli, as well as the other shrimp/partner gobies, have excellent eyesight, and like a watchmen/guardian, it maintains constantly vigilant against potential predators, while the shrimp continues the digging and maintenance activities. This way, the shrimp gets security, and the goby gets a safe home with cleaners. What a clever way for 2 small creatures to increase their chances of survival!
A very interesting aspect of this particular symbiosis is the communication between goby and shrimp. So far it's been established that when a predatory fish approaches the burrow entrance fast, the goby escapes into the burrow. This escape reflex is very similar to that of other fishes. However, when a predatory fish approaches the burrow at a moderate distance or speed, the goby flicks its tail, and/or dorsal fin, in quick bursts, so that the shrimp, who’s in touch with the body of the goby via its antennae, notices the message and stays below ground. This type of messaging is signalling a threat level below the "full escape", and is information specifically communicated to the shrimps!
Since behavioural science of marine life is still in its infancy, hopefully, scientists will bring us more interesting facts about their inter-species communication in the future. Perhaps even more remarkable, is that this symbiotic relationship between shrimp and goby lasts a lifetime. They start bonding as juveniles and remain together as adults, spending their days foraging together and sharing a burrow. It is still unclear why these two species have developed such a high level of co-dependency, but the symbiosis is working well for both creatures. Gobies eat micro-fauna, and sometimes small fish that they find near the bottom.
The shrimps, on the other hand, feed on what they find during their burrowing and therefore do not compete with the gobies for food. While shrimp reproduction isn’t all that remarkable, the reproduction of gobies on the other hand has some peculiar aspects. During the mating season, the male and female gobies start a wild circular dance in an extended side corridor of the burrow. They touch and stimulate each other from head to tail, which causes sand and gravel to fall from the ceiling and walls. The shrimp’s digging/cleaning actions play an important role in ensuring that the mating ritual can continue, as gobies don’t have the ability to transport the sand themselves.
Hence, the preparation of the gobies breeding chamber, as well as the constant maintenance during the actual mating, and by extension, the successful procreation of the particular goby species, is only possible with the shrimp’s assistance! If by now you’re wondering how gobies and shrimps find each other in the first place, know that science hasn’t found a definitive answer to that question yet. Marine biologists have conducted numerous experiments to determine who finds who, and how, but currently, this question remains one of nature’s enduring mysteries ...
Take a Minute XXXIII: Sarasvati Anemone Shrimp: Periclimenes sarasvati
In this episode of “Take a Minute to Relax”, we would like to focus your attention on a small treasure, that’s easy to overlook: Sarasvati Anemone Shrimp (Periclimenes sarasvati). This little beauty is a commensal shrimp, genus of semi-transparent within the family Palaemonidae, often living symbiotically. It has been labelled with many common names, depending on the region of the Indo-Pacific where it is found. Anemone- Carid, Cleaner, Commensal, or even Glass shrimp, due to the fact that their bodies are almost transparent.
However, the scientific name “Periclimenes sarasvati” rolls so nicely of the tongue, and is beautifully befitting! It has been named after the Hindu goddess Sarasvati, which is the goddess of knowledge, music, arts and science. Periclimenes sarasvati is relatively easy to distinguish from other species in their genus, by the red stripe(s) going through their white eyes. The one in this particular shot also seems to have a bundle of pink eggs in her abdomen. One of the advantages of a transparent body!
This pretty creature grows to a maximum of 2,5 cm and can be found on coral reefs from 2 – 40 meters of depth. They prefer to live in small groups and will form symbiotic relationships with host species, like anemones and corals. It is at these host species, that the Periclimenes sarasvati will set up shop, and open their cleaning business. Because most all reef and pelagic fish species enjoy a good cleaning session once every so often, to rid themselves of parasites, help clean any wounds they might have, and lower their overall stress levels, these cleaners are generally very well respected.
However, when one is so small, it can’t hurt to provide your services from the safety of a voracious killer like an anemone, to which one can retreat, when a customer is showing signs of bad behaviour/intentions. These cleaning stations are fairly easy to spot for anyone diving, and/or snorkelling on a particular reef. When a reef fish hovers over, or next to an anemone or coral for a while, one can be pretty sure that there is a cleaning service in progress at that particular spot.
If and when one manages to approach a cleaning station in such a manner that disturbs neither the “staff” nor the “customers”, one gets the opportunity to observe the behaviour of both, the personnel and their clients, in this cleaning operation. Periclimenes sarasvati tend to hover a fair distance over their host species, to advertise that they’re willing to receive customers. When a fish approaches, they first retreat to the safety of their host’s stinging tentacles, from which they will assess if their potential client is giving the right signals. During this time they may “clap” their hands/arms together in a particular sequence, advertising their willingness to start the cleaning activities.
If, and when the customer displays the right submissive behaviour, signalling they are ready, and willing to be cleaned, without any “funny business”, multiple Periclimenes sarasvati will go to work and clean the customer’s skin, potential wounds, gills, and even the inside of their mouths. Quite some fish will change skin colour before, and during their treatment, to inform the cleaners that they will behave appropriately during the proceedings. After observing all of this, one might even be rewarded with a free manicure themselves!
Take a Minute XXXIV: Thorny Seahorse (Hippocampus histrix)
In this episode of “Take a Minute to Relax”, we invite you to look deep into the eye of one of the most effective and successful hunters, not only of the aquatic realm but of the entire planet: Hippocampus histrix, a fish that also goes by the common name of Spiny or Thorny seahorse.
Their scientific genus name “Hippocampus” is derived from the Greek words “Hippos & Kampos”. “Hippos” means horse, and “Kampos” means sea monster. The Romans later adopted it as “Hippocampus”. In both Hellenistic and Roman imagery, it was depicted as a two-hoofed horse creature with a fishtail, that drew the “chariot” of the sea god Poseidon/Neptune. Looking at the creature, it’s not too hard to understand why science adopted the “Hippo” part of its name, but the “Kampos” (sea monster) part, seems a bit far fetched at first. Also, histrix is rooted in ancient Greek and means spiny.
With their elongated bodies, covered in an armour of bony plates, and prehensile tails, they look nothing like any of the traditionally shaped fishes. However, equipped with fins for propulsion, gills for breathing, and even a swim bladder to control their buoyancy, these oddly shaped creatures are indeed fish from the family Syngnathidae. They usually can be found in shallow tropical-, and temperate waters, but also do occur in some colder water in places like New Zealand, Argentina, and Canada.
Their usual lifespan ranges between 1-5 years. But there’s a lot more to this creature, than just its strange appearance. To say that seahorses are not very good swimmers, would be somewhat of an understatement. Their main source of propulsion is delivered by a small fin on their back, that although it can flutter up to 50 times a second, gives them very little speed. They’re however capable of covering large distances, by simply using their prehensile tail to hang onto pieces of seaweed and/or debris, which can carry them to far of places.
Hippocampus does neither possess any teeth, nor stomach! Therefore, the food they consume passes through their system so quickly, that they have to eat almost constantly, in order to survive. Their diet consists of plankton, plants, small fishes, and crustaceans, like shrimps and copepods. Adults will typically have between 30-50 feeding sessions a day. Baby seahorses are called “fry”, and like the teenagers of our own species, can consume an incredible amount of food. Their food intake can be an astonishing 3000 food pieces a day!
The eyesight of seahorses is excellent, and they are able to move their eyes independently from each other, making it easier to spot their food, whilst using their tube-like snout as a suction device! Due to their lack of movement, and ability to blend in with their environment, their tiny prey has no idea of their presence, until it’s too late. They have one of the highest success/kill rates of any creature in the animal kingdom. 90 %, compared to say lions with a 25%, and even sharks are well below 60%.
Hippocampus are essentially serial monogamists and stay with one partner for as long as possible. They also have voices and can make grunting sounds, as well as clicking noises. Some of these noises are made on a couple’s daily romantic “confirmation dance”, that takes place each morning, whereby the couple dances and pirouettes together for a couple of minutes. This often results in the iconic heart-shaped pose of their heads and upper bodies, before they separate for the rest of the day.
They have this morning ritual to confirm the other partner is still alive, reinforce their bond and synchronize their reproductive cycles. After courtship, the female deposits her eggs in a specialised breeding pouch of the male, where he fertilises them. This “male pregnancy” lasts between 10-25 days, depending on the species.
The number of young released by the male seahorse at the end of term, are on average between 100–1000 babies. Under normal circumstances, less than 1% of these will ever make it to adulthood, which explains the large number of offspring. Whilst the male is taking care of the “pregnancy“, the female can use her energy into producing the next batch of eggs.
Seahorses can not only change the colour but even the texture of their skin. Not just for camouflage purposes, but also to communicate and express their emotions. They do this by contracting or expanding pigment cells known as chromatophores. These muscle manipulated cells can be controlled by the nervous system, for quick changes in appearance, or by hormones for slower more flamboyant changes. On top of that seahorses are masters at the game of hide and seek. They have for instance figured out that humans often manage to find them, because of their iconic horse-like body shape, and therefore often lay down flat on the bottom, in order to remain hidden.
What an incredible creature this is!
Take a Minute XXXV: Roughhead Blenny (Acanthemblemaria aspera)
In this minute of relaxation, we would like to introduce you to a creature, that despite being quite the character, is often overlooked by most that visit the tropical reefs of the Caribbean: Roughhead Blenny (Acanthemblemaria aspera). Looking at the creature, it’s easy to understand how this name came to be. The so-called “roughness” refers to the slender appendages/hair-like growth on the blenny’s head named “cirri”. Incidentally, the word “cirri” is derived from the plural version of the high altitude cirrus cloud, which are able to create these beautiful, whispy, and streaky patterns in the sky. Just to give you an idea, of how awesome its haircut is!
Some might say that Roughheads look a bit pre-historical in its appearance, and they wouldn’t be wrong with that observation. Fossiles of Blennies date back to the Paleogene period, which started about 65 million years ago. To put that in perspective, that is around the time Keith Richards was born!
If one intends to admire Acanthemblemaria aspera in all its glory, as well as its amazing haircut, of course, it would probably be best to bring some form of magnification device, be it a macro lens or a magnifying glass, for this funky little fish grows to a maximum size of 4cm/1”. They inhabit shallow coastal waters from 2-20m/6-60ft and are not overly picky about where they live. They are known as burrow creatures and find a place to live in just about every nook and cranny of the reef, if not in the corals themselves. Not that they construct their own burrows, but more that they occupy holes left by other marine life, like worms and molluscs. A bit like a squatter with good hair, so to say. Although some of them have been known to bury themselves in the seafloor.
They come in many different colour variations, and can adapt their colouration to blend into any neighbourhood they happen to find themselves in. That being said, the females are often more lightly coloured. They’re oviparous, and after mating the female covers the walls of the male’s burrow with her eggs, and leaves them for him to defend until they hatch. After which the young fry go through a 22-day pelagic phase, and eventually settle down in a new area to find a home for themselves. They have excellent eyesight and prefer to dine on drifting, floating, or falling amphipods and/or copepods, that happen to pass by their burrows. This “hunting” action results in a kind of swaying head movement, which has led to the creature’s nickname, the “Stevie Wonder Fish”.
Another stunning creature, in another beautiful part of this amazing blue planet!
Take a Minute XXXVI: Feather Duster (Tube) Worm (Sabellastarte spectabilis)
In this session of relaxing minutes, we would like to introduce you to a critter that uses a flamboyant feature to mask what many people would deem an otherwise gross appearance. Yes, Sabellastarte spectabilis is, despite its beautiful name, not some fluffy plant or coral in a variation of colours, but in fact a humble worm. However, don’t let this little detail change your opinion of this creature. Sabellastarte does really make an effort to look more appealing than just another worm. As a matter of fact, another member of this family of worms, the Christmas tree worm (Spirobranchus corniculatus), was the inspiration for the beautiful Helicoradian plants on the moon Pandora, in the hit movie Avatar (2009).
Sabellastarte spectabilis has a segmented tubular body of around 8cm long, and roughly 1cm wide, and can be found in the more sheltered regions of the tropical reefs and lagoons around the world, ranging from 5-100m in depth. This worm creates a leathery-looking tube from its own mucus secretions and attached sediment and/or sand. Others use calcium carbonate or chitin, and some even have a trap door to close their tube off, in case of lurking danger. These tubes are then embedded, or attached to a variety of substrates, from where they compete with other organisms for food and space. Some even have the ability to physically, or chemically burrow into corals and/or limestone.
As a defence mechanism, these creatures are able to quickly retreat into their tubes, when disturbed by potential predators. It may come as a surprise, but Sabellastarte has eyes! And some species have more than others. They have multiple eyes along the sides of their bodies, as well as appendages called chaeta, which allow the worms to anchor themselves inside their tubes and aid in the retraction response. These eyes will likely let the worm know whether it’s still within the safety of its tube. Perhaps they might even locate areas of the tube that need maintenance. In some species, eyes may also be found on their heads and/or on the highly specialised, feather-like feeding tentacles, that stick out of the tube. That’s a lot of eyes for one creature!
While some of these eyes might simply detect light and darkness, others might be more complex compound eyes capable of producing a picture and detecting movement. Similar to that of more active predatory marine worms, or flying insects. Like many other sedentary life forms, Sabellastarte is a “filter feeder” that dines on planktonic prey and detritus brought in by the currents. They do this by using the only visible part of themselves, their beautiful exposed plumage. It is this plumage giving them the common name feather duster tube worm.
Each feeding tentacle is called a radiole and is covered by feather-like pinnules and a sticky mucous, that form a fine mesh net, to capture any food particles that float by. Short vibrating microscopic hair-like structures, called cilia, cover both the radiole and the pinnules. Cilia can also be found in humans, where it lines our lung surface and windpipe, and capture and remove dirt particles and mucous. Vibrating cilia on the ventral surface (underside) will create an up-current, directing particles through the radiole and pinnules, where they can be caught.
From there, a decrease in pressure makes the particles fall into the ciliated groves on the dorsal (upper) side of the pinnule, from where they will be transported via several other ciliated, mucous-lined food grooves down to the actual mouth. There the particles will be sorted. The edibles will continue their journey into the worm itself, the rejected particles will be removed via other ciliated grooves away from the mouth. Some of these particles will be stored, and used for repairs on the actual tube when it has sustained damage.
In addition to all that, the large surface area of the plumage also acts as gills, making them technically known as branchiae, since they’re used for respiration. With so many important functions located in a small area, one would think that if a predator was quick enough to bite a chunk of the plumage, the worm would surely die. But sabellastarte has the uncanny ability to regenerate damaged or lost body parts! Several species have shown to be able to control the loss of the crown of tentacles, a process known as autotomy. Lizards have a similar process whereby they intentionally lose a tail in order to distract a predator and enable their escape.
They reproduce by spawning, releasing eggs and spermatozoa in the water column in the hope that they will find one another before any predator, including themselves, get to them. Strangely enough, Sabellastarte is also capable of reproduction by fragmentation, also known as „budding“. So you see, there’s a very interesting creature hiding behind those colourful plumes!
Take a Minute to Relax XXXVII: Slender Filefish (Monacanthus tuckeri)
In this minute of relaxation, we bring you another Caribbean addition in our series „Take a Minute to relax“. The small but beautiful Monacanthus tuckeri, a.k.a. the Slender filefish.
Although most individuals encountered, range between 2-5cm in length, they can potentially grow up to 10cm! They have laterally compressed, slender, elongated bodies, with a tapered snout, and protruding eyes that are located high on their heads. Filefish have a slender retractable spine on top of their heads, which is incorporated in their first dorsal fin. This spine/dorsal fin actually contains two spines, whereby the second, far smaller one, is used solely to lock the first spine into its upright position. This explains the family name Monacanthidae, from the Greek „monos“ meaning „one“ and „akantha“ meaning „thorn“.
Like their cousins the triggerfish, filefish have small gill openings and their pelvic fins are lacking. Instead, there is an extension of the pelvic bone, known as the pelvic rudiment, with skin attached to it. This „pelvic girdle“ is capable of moving up and down in many species, to form a large “dewlap”, which can make Monacanthus appear much larger than it actually is. Some filefish erect the dorsal spine and pelvis simultaneously to lodge themselves into place, making it more difficult for a predator to remove the fish from its shelter. It may also be used for communication purposes with other filefish.
The small mouths of this creature have specialized incisor teeth, on the upper and lower jaw. In the upper jaw, there are four teeth in the inner series and six in the outer series; in the lower jaw, there are 4-6 in the outer series only. These teeth allow them to be opportunistic omnivores, that dine on macroalgae, filamentous algae, seagrasses, coralline algae, sponges, hydrozoans, bryozoans, and tunicates. A small portion of their diets includes foraminiferans (shelled protozoa), polychaete worms, smaller species of bivalves, snails, ostracods, amphipods, and shrimp.
They have non-overlapping scales that bear “spicules”, which are small, needle-like anatomical structures, protruding from the centre of each scale, giving them the rough and tough, sand-papery skin, that together with its body shape inspired the filefish’s common name. Monacanthus isn’t a particularly strong swimmer, and relies more on crypsis, camouflage, and hiding, to avoid being eaten. Slender filefish are often found around soft corals, like sea whips, rods, and fans, but also in seagrass, hydroids and algae, where they align their movements perfectly with that of the ocean’s swell. Despite lacking the power, their body shape allows them to manoeuvre effortlessly around these complex environments. They love hanging out vertically in the water column, and on top of that, these incredible fish can quickly change their colouration and patterns, making them not easy to find.
But when you find one of these small ocean dancers, enjoy their performance for as long as you can! For it might all be over, in the blink of an eye …
Take a Minute XXXVIII : Harlequin Crab (Lissocarcinus laevis)
This relaxing Minute features a colourful character, and its relationship with anemones, as well as certain coral species, and even some sea cucumbers: Harlequin Crab (Lissocarcinus laevis). In it, we see a Harlequin crab caught with its hand in the cookie jar, as it tries to get to some food before the anemone can eat it.
As we look closely at this little scoundrel, we can see that the last hind legs are larger and flatter than the other ones. This is because they belong to the Portunidae family, also known as swimming crabs. With these flattened hind legs, these creatures are capable of swimming through the water column, when the need arises. However, like most swimming crabs, Lissocarcinus laevis prefers to keep its feet firmly on the seafloor, or on its host for that matter. But it’s nice to have options.
This small, yet ornate species of swimming crab has a very smooth, reddish, light brown carapace with large white to yellow spots and markings which are often interconnected. So smooth in fact, that their genus name actually means „smooth crab“. Its claws are banded with white and brown/red bands. The females can be slightly larger than the males and can grow to a width of about 3,5cm, with a body that is wider than it is long.
As with most crustaceans, after the eggs are fertilised by the male, they’re carried under the body of the female, who will protect and oxygenate them, until it’s time to release them. Once they hatch, the larvae go through a pelagic phase of several weeks, before settling down and growing into their adult form.
They are guided to their host species, by the chemicals these host creatures release, to attract their symbionts. Interestingly enough, the chemicals produced by these host species might actually be meant to deter predators and parasites, but for Lissocarcinus laevis it’s a chemical trail, that leads to a compatible host, and hopefully the start of a long-lasting symbiotic relationship.
Chemical sensing is considered to be the most ancient and universal form of communication in the biosphere. All living organisms are able to detect chemical cues in their respective environments. These cues allow for different types of intra- and interspecific interactions between organisms. For example, mate recognition, prey/predator interactions, and symbiotic associations. The communication between symbionts and their hosts is needed to ensure appropriate host selection, as well as maintaining the symbiotic relationship through time, but is just one of the many chemical conversations that are taking place below the surface of the ocean.
Although the symbiotic relationship of the Harlequin crab with its host is very common throughout the Indo-Pacific, the exact nature of the relationship between the hosts and symbiont is still somewhat unclear. Something which has made it very hard for scientists to classify their relationship on the symbiotic spectrum. It is currently listed as “commensal”, meaning one species gains benefits from the relationship while the other neither benefits nor is harmed.
Harlequin crabs are predators, that eat shrimps and other tiny planktonic organisms, as well as leftover food from their hosts. Scientists believe it might also be feeding on parasites from its hosts. If true, it might mean another shift on the symbiotic spectrum, but no studies have been done yet to prove this hypothesis.
Take a Minute XXXIX: Whale shark (Rhincodon typus)
After many episodes that focused on the smaller and more cryptic marine life, in this „Take a Minute to Relax“ we’d like to introduce you to the largest fish in the ocean, the whale shark (Rhincodon typus). The name of this creature has confused people for many years, and unlike what it seemingly suggests, this creature is in no way related to whales.
The only reason this was added to its name, was to give people an idea about the immense size of this fish. Rhincodon typus can grow up to a size of around 18 metres when given the chance. Although most adults that are encountered by people are around 12 metres in length. Not only are these creatures very large, but they can live to be around 130 years!
Despite its enormous size, and the amount of research that’s been done on them, much of the whale sharks‘ life is still shrouded in mystery. This is probably due to the fact that whale sharks migrate and can easily travel great distances. One particular tagged specimen was recorded to travel nearly 15.000 kilometres, in a little over 3 years. On top of that Rhincodon typus can dive to a depth of around 1,500 metres. All of this makes it very hard for scientists to study this iconic creature.
As mentioned before, not everything is known about the reproductive behaviour and life cycle of whale sharks. But what we do know is that Rhincodon typus reaches sexual maturity around 30 years of age, and is ovoviviparous. Meaning that the female lays eggs and keeps them inside of her body. When fertilised, they will hatch, but remain safely inside until they are fully formed and strong enough to start their life outside of their mother’s body. A whale shark can give birth to about 300 pups that are about 40-60 cm in length, and already look like a miniature version of their parents.
Although whale sharks are no threat to humans and are referred to as the gentle giants of the ocean, they do have teeth. In fact, they have more than 3,000 teeth stacked in 300-350 rows, which is more than any other shark species. Despite all these teeth in their enormous 1-1,5 metre mouths, these sharks are filter feeders. Meaning that these animals feed by straining suspended matter and food particles from water. They typically do so by letting the water pass over a specialized filtering structure. Due to the fact that they play such an important role in clarifying water, filter feeders are considered to be ecosystem engineers.
The whale shark also feeds by active suction feeding. This occurs when they are in a vertical position. The animal opens and closes its mouth, sucking in volumes of water, then expelled them through the gills. Rhincodon typus can process over 6,000 litres (1,500 gallons) of water each hour in this fashion! The whale shark’s most common diet consists of plankton, copepods, krill, fish eggs, jellyfish, red crab larvae and small nektonic life, such as small squid or fish. To eat, the whale shark opens its formidable sized jaws and passively filters everything in its path. This technique is called “cross-flow filtration”, and is similar to how some bony fish and baleen whales feed.
The distinct pattern of white spots on the whale shark’s back is unique, and no two are alike. Which makes them a bit like human fingerprints, and helps scientists identify individuals. Since swimming with this creature is high on the list of divers and snorkellers alike, we can all contribute by making our photos available to organisations and researchers that study this incredible creature.
Take a Minute XL: Hawksbill Sea Turtle (Eretmochelys imbricata)
In this relaxing Minute, we invite you to swim alongside one of the more famous and beloved ocean creatures, the hawksbill sea turtle (Eretmochelys imbricata). These marine reptiles, and yes they are reptiles, have been roaming the world’s oceans for an incredibly long time. It is believed that the “Cheloniidae” family, the name of these marine turtles, has been living on our planet since the last Mesozoic Era, more than 100 million years ago! Making them some kind of living fossils.
Their scientific name Eretmochelys imbricata, is derived from the Greek words “eretmo” meaning oar referring to its oar-like flippers and “chelys” meaning turtle. The second part of the scientific name “imbricata” comes from the English word ‘imbricate’, which means ‘having overlapping edges’, and refers to the overlapping scales of the Hawksbill’s carapace. There are currently actually 2 subspecies known to science, namely E. imbricata imbricata (a.k.a. the Atlantic Hawksbill), and E. imbricata bissa (a.k.a. the Indo-Pacific Hawksbill).
The Hawksbill is one of the smaller species of sea turtles, growing up to about a meter in length. It has a characteristically narrow, pointed beak and a beautiful patterned shell/carapace, which has serrated edges towards the lower end. These turtles are in fact omnivores that will dine on a wide variety of food sources, including jellyfish, corals, fish, anemones, molluscs, marine worms, crustaceans, and other plants and animals. However, Hawksbill turtles feed primarily on sponges.
They show a great level of feeding selectivity, in the way that they only eat certain species of sponges, some of which are toxic to other animals. But there is more to their diet. In fact, their type of feeding provides a great service to other marine life on the coral reefs. Without hungry hawksbill turtles, the reefs would quickly overgrow with sponges, taking the space for slower-growing corals to thrive. Hence, hawksbills play an important role in the ecosystem and contribute to the overall health of coral reefs and wider marine life.
Hawksbill sea turtles reach sexual maturity between 20 and 35 years of age (around 20 in the Caribbean and 30-35 in the Indo-Pacific). It is estimated that they can live between 30 and 50 years in the wild. Hawksbills will lay eggs every 2-4 years during those sexual mature years. Nesting is the moment when the female turtles, who have come back to the place of their own birth, leave the water. This allows observing them on the sand of small beaches, where they dig a nest to lay their eggs. Such a nest is usually about 50cm /19” deep.
After they have laid their eggs inside, they cover them with sand again. Each egg is approximately 36 mm in diameter and 28 g in weight. About 60 days thereafter, the young ones will hatch. Interestingly enough, temperature determines the sex of these hatchlings. When the temperature is around 29°C/ 84.2°F, the male-to-female ratio is about 1:1 in the nest. When the temperature rises, more female baby Hawksbills turtles will be born. If it drops, the baby Hawksbill turtle males will dominate the hatching. This fact is worrisome, not only to scientists, as the averages temperatures on our planet continue to rise.
Unfortunately, these beautiful creatures are critically endangered and therefore listed in appendix I of CITES, a multilateral treaty to protect endangered plants and animals, as well as the „Red list“ of IUCN (International Union on Conservation of Nature). These listings lead to the fact that the trade of this turtle’s beautiful carapace/shell has been made illegal, in an effort to conserve the population. Despite this, the Hawksbill turtle shell is still found in souvenirs and jewellery. In fact, it’s still the most frequently confiscated illegal item by customs officials …
This clip was filmed by Yoeri diving at Balicasag island, the Philippines, with a Sony V1p in an Amphibico housing in 2010. We have presented hawksbill sea turtles to you before. Watch „Take a Minute VIII“ or read more on Statia‘s sea turtles 1: Species, sex & individuals.
Take a Minute XLI: Goniobranchus kuniei
In this relaxing episode of “Take a Minute”, we would like to introduce you to a pretty creature named Goniobranchus kuniei. This colourful little beauty is a dorid nudibranch, of the Chromodorididae family. The Order Nudibranchia of which this creature is part differs from other sea slugs. The name “Nudibranchia” is derived from the Latin word “Nudus” meaning naked, and the Greek word “Branchia” meaning lungs/gills. This describes the breathing organ that these creatures carry on their backs.
Goniobranchus kuniei is widely distributed in the central, and west Pacific regions. They like water that is of a temperature between 21°-27° C and can be found at depth of between 5m-40m. A pattern of blue spots with pale blue haloes on a creamy mantle, and a double border to the mantle of purple and blue let them stand out. They are known for raising and lowering the entire edge of their mantle in a smooth single motion, creating a bowl-like shape to the mantle and leaving its foot and oral tentacles exposed for a moment. There are two ways. Either, they just raise the anterior or posterior portion separately, or they move the whole mantle edge in a wave-like motion from front to back.
Being closely related to the sea slug family, Nudibranchs are slow-moving creatures. They have millions of tiny hairs on the bottom of their fleshy “foot”. These help them maintain a good grip, whilst they move forward by expanding and contracting the muscles in their “foot”. In fact, some Nudibranchs can even swim, or propel themselves along, by muscular contraction of their “foot” in a flapping fashion, to escape from would-be predators.
Being small, in the case of Goniobranchus kuniei up to around 5 centimetres, and being slow, Nudibranchs would be easy prey for any hungry predator on the reef. However, these creatures have come up with an ingenious solution to that problem. Goniobranchus kuniei feeds on sponges with a rasp-like tongue. These sponges contain toxins that the nudibranchs will store in their flesh, and can secrete through their mucus. This makes them either very distasteful or outright dangerous to eat. They advertise their chemical properties by their flamboyant appearance. Their bright flashy colours are a warning to would-be predators.
Although most have some form of eyes in their heads, these mostly provide no other visuals than light and shade. However, they “see” their surroundings through chemical interpretation, which they pick up with two specialised organs on the top of their heads, named rhinophores. Since these are very important organs, the rhinophores of the Goniobranchus kuniei arise from slightly raised translucent pockets into which they can withdraw. All these aspects together, make these magical creatures the true chemical brothers of the ocean.
Like all members of the order of Nudibranchia, Goniobranchus kuniei are simultaneous hermaphrodites. During mating, these creatures engage in a “fencing match” with their penises, in order to induce one of them to act like a female. The one who is first to penetrate the body wall of the other will be the dominant male, whereas the other will assume the role of a female. After mating, the eggs will be deposited in a beautiful ribbon on a particular substrate, where the offspring can develop and hatch to start their pelagic larval stage. Eventually, they’ll find their way back to the reef, as well as their food, through chemical clues given off by the reef.
What an incredible, amazing and beautiful creature this is!
Take a Minute XLII: Ornate Ghostpipefish (Solenostomus paradoxus)
In this Minute of relaxation, we would like to introduce you to a very cryptic creature, that is very much loved by divers and snorkellers alike, the Ornate Ghostpipefish, a.k.a. Solenostomus paradoxus. In this clip, we see the Ornate Ghostpipefish in one of its favourite hiding places, namely among the feeding arms of a crinoid named a Feather Star.
Solenostomus paradox is a stunningly beautiful creature, that has a bizarre way to move around. It spends all of its life swimming with its head down. They can be recognised by their distinctive body form, with slender appendages on the body and fins. It has deeply incised membranes in the dorsal, caudal and ventral fins. Ornate Ghostpipefish come in different colourations; White-Red, Gold-Red or Black-Golden, and grow to a maximum size of around 12 cm.
They are fairly widespread in the Indo-West Pacific and can be found in depths ranging from 5m-35m. Although they are closely related to Seahorses, they differ in several ways. An Ornate Ghostpipefish’s head is held at an angle to the body, but not to the extent of that of seahorses. Ghostpipefishes have two dorsal fins whereas seahorses only have one. In addition to that, Ghostpipefishes do not have an actual brood pouch in which they rear their offspring. Instead a female Ghostpipefish, as opposed to the male seahorse, looks after the eggs in a pouch formed by her modified ventral fins.
These fins are greatly expanded and united with the abdomen along the upper margin, and together form an improvised brood pouch of sorts. The females carry up to 350 eggs in this ventral brood pouch. Solenostomus paradoxus can often be found in mating pairs, which makes it easier to spot the difference between the two. The females are much larger in size, with males being around 37% smaller. However, as with much other marine life, they are able to change their sex during their lifespan.
After the eggs hatch, they will be released into the ocean’s currents, to start their pelagic phase as tiny larvae. Once they have grown a little more mature, they start to settle on the sea floor. Transparent in colour they try to protect themselves from predators, by being as inconspicuous as possible. Before long, they begin to mature even more. When they reach the phase in their lives that they are old enough to breed, they head up to an area which offers them good hiding places, as well as potential mates. This is where they start to gain their beautiful colourations, camouflaging alongside Crinoids, Fan coral, Black coral bushes, and algae.
The scientific name Solenostomus paradoxus roughly translates to marvellous tube mouth, which honestly sounds way better than their common name. “Solen” means tube, “stoma” is the mouth, and “paradoxus” means marvellous/unexpected. Overall quite an apt description of this gorgeous creature. Their tube-like mouth turns out very useful in their hunt for food. As they slowly hover around in a face-down position, their tube-like mouth can create quite an under pressure when opened quickly. In this fashion, they suck up their unsuspecting prey. Solenostomus paradoxus mainly feeds on mysids, small shrimps, or other tiny crustaceans, but can also eat small fishes at times.
These incredible creatures are a delight to watch!
Take a Minute XLIII: Tiger Shrimp (Phyllognatia ceratophthalma)
In this episode of relaxation, we would like to focus your attention on a gorgeous little creature that goes by the name Tiger Shrimp, Phyllognatia ceratophthalma. Since its scientific name is of very little help this time, we like to throw in some of its common names: Spiny Tiger Shrimp, Bongo Shrimp, and Horned Bumblebee Shrimp.
This very shy and cryptic shrimp grows up to about 2cm, and likes to hide out in sponges, rubble, algae or broken coral, or in an encrusted mix of all of the above. They look extraordinary, with their beautiful colouration. As they grow older, spikes randomly jutting out from their bodies.
Most shrimps are omnivores. However, the diet of the Tiger Shrimp is not totally clear yet. If it behaves similar to other shrimps in the family of Palaemonidae, it feeds on the feet of various Echinoderms, like seastars, brittle stars, urchins and sea cucumbers, for example. Other than using its legs to move around for short distances, the Tiger Shrimp is actually able to swim.
They use a technique named drag swimming, by which they use a cyclic motion where they push water back in a power stroke and return their limb forward in the return or recovery stroke. When they push water directly backwards, it moves their body forward, yet as they return their limbs to the starting position, it pushes the water forward, which in effect will move them back to some degree. This opposing force is called drag, and causes drag swimmers to employ different strategies than lift swimmers. Reducing drag on the return stroke is essential for optimizing efficiency.
As one can admire in this clip, the Tiger Shrimp has beautiful eyes. Each ommatidium (optical unit consisting of photo-receptors and usually multiple lenses) is equipped with a set of plane mirrors. The superposition compound eyes are aligned at right angles, forming a square. This is causing light that enters the eye at an angle to encounter two surfaces of each mirror box rather than only one surface. In this case, the pair of mirrors at right angles acts as a corner reflector, which reflects incoming light rays through 180 degrees, irrespective of the light rays originally came from. This ensures that all parallel rays reach the same focal point and means that the eye as a whole has no single axis, which allows it to operate over a wider angle.
Since so little is known about this beautiful creature, we see it as an ambassador for reef/ocean conservation. Who knows what wonderful abilities and behaviour we might miss out on, when a life that has hardly been studied, disappears from our oceans forever!
Take a Minute XLIV: Long-arm Octopus (Abdopus sp.)
It is time to take a minute to relax again. Sit back and enjoy the mesmerising beauty of a Long-arm Octopus (Abdopus sp.). Even though this octopus is quite common in the Philippines and Indonesia, it hasn’t been scientifically described yet. Hence, its scientific name just ends in sp. for species. As there is another long-armed octopus in the Atlantic (Macrotritopus defilippi), our cephalopod is often called a White V octopus instead.
Abdopus sp. likes living around (black) sand slopes with mild currents. The head of this octopus is usually around 6 cm in size, while the arms can reach 15 cm in length. These long arms are marked with a series of white spots on the body and a “V” shaped mark on the back of the head. Generally, they are coloured light brown to brownish red. When this octopus is resting inside a small hole in the sand, usually only its head sticks out. In general, long-arm octopuses are quite shy. Yes, it is octopuses, not octopi (Let’s talk scientifically: Pictures and classifications of marine life).
In this case, we were lucky enough to meet the long-arm octopus (Abdopus sp.) while it was out and about searching for food. Same as mimic octopus which is closely related to them, the long-arm cruises along the bottom in a teardrop shape.
We wrote a long story on the body, brain and nervous system of octopuses in „Take a Minute XXI: Coconut Octopus (Amphioctopus marginatus)“ as well as what they eat and how they mate. Therefore, we focus on other aspects regarding their arms now. First of all, octopuses have arms, not tentacles. There are other cephalopods with tentacles such as cuttlefish (Savvy softies: Octopus, cuttlefish and squid), but an octopus is all about arms! More precisely, eight arms. Hence, the name octo (Greek for eight). Even though it was called a foot first (pus from pous for foot).
Maybe, feet turned into arms when people observed what an octopus can do with them. Each arm has around 280 suckers (~2,240 suckers in total). They are used for: Moving, pushing, pulling, grasping, camouflage, mimicry, fighting, mating, capturing prey and tasting.
When an octopus sustains an arm wound, they don’t get a scab or scar as we would. Instead, a layer of cells called epithelium (the same cells that make up our skin layer) covers the wound and beneath this, the regeneration process begins. A study reported that the first sign of regeneration came in the form of a tiny knob on the arm edge, 3 days after injury. After 11 days, they observed a protrusion which turned into a hook-like structure by day 17. By day 55, a complete structure (mini arm) was visible and by day 130, the new arm tip had fully regenerated.
Some species of octopus can even drop an arm to confuse a predator. It can keep moving for up to five hours. This defence tactic is called “arm dropping” and apparently some String-Armed Octopuses manage just fine with only 2 arms! However, this species can regenerate its arms as quickly as 6-8 weeks.
For hunting, octopuses use an arm or more to feel out the nooks and crannies in the reef and grab anything wanting to escape with another one. A different technique is net fishing. In this hunting strategy, the octopus spans its whole body over a small piece of coral or such. Only when it has blocked all escape routes, it starts poking around with its arm to get its prey out of hiding and into the net with eight arms. The longer the arm, the easier the catch? Possibly.
We hope there will be more studies on this interesting marine creature soon. Subscribe to our channel for more ocean stories.
Besides, we ask for your help in the name of octopuses. Spain plans to set up the first worldwide octopus farm. Usually, industrial farming leads to problems, be it inside the ocean or on land. Read more on this project and its problems and put our name down against octopus farming here. What to amplify your voice? There are more petitions out there: here and here. Let’s care and share!
Take a Minute XLV: Giant moray eel (Gymnothorax javanicus)
In this round of „Take a Minute“, we present you with the Giant moray eel (Gymnothorax javanicus). Granted, at first glance, it neither looks relaxed nor relaxing. However, it opens and closes its mouth simply for breathing. Moray eels have relatively small oral cavities with the gills sitting behind them. The constant gaping pumps oxygen-rich water with fresh oxygen through. That is why morays often swim with their mouth open.
If a moray wanted to make a thread display, it would hold its mouth wide open to show off its sharp pointy teeth. There is a second row of teeth in the upper jaw, assisting in grabbing prey and holding it tight. By the way, all of these teeth are pointing backwards. But not to worry, same as with all of our aquatic friends, they rather flee from humans if given the chance than attack. Only cornered animals with no way out, e.g. in the case of people hunting for crayfish and sticking their hands into cracks on the reefs, will attack. Okay, and some species attack when nesting and guarding their young. Surely, we can all relate to that.
Gymnothorax javanicus is the biggest of all moray eels in terms of body mass. It can weigh more than 30 kilograms and can grow up to three meters in length (Wikipedia). However, the longest moray eel is the slender giant moray (Strophidon sathete). Juveniles are still light brown with large black spots, while adults turn darker brown with leopard-like spots behind the head.
Giant morays are carnivorous and hunt their prey along the reef – often but not exclusively at night (Sea unseen). They go after fish as well as crustaceans or octopuses. Sometimes, groupers such as roving coral groupers invite giant morays to hunt with them by shaking their head in the direction of the prey. While the moray can get into the reef and this way may scare prey up and out, the grouper hunts above the reef and might scare prey to seek refuge in the reef (Biology dictionary). Either way, the other predator is waiting. Similarly, Yoeri observed giant morays hunting together with jacks and napoleon wrasses. If the giant moray can‘t get the prey down in one go, it either wraps itself around it to crush the victim until it is small enough to be swallowed, or it tears pieces from the prey and eats it bite-by-bite.
When researching the giant moray I found some pages and videos referring to it as alien-like. I think they got it wrong: The alien from the movie Alien is clearly moray-like. Moray eels have a second set of jaws with teeth in their throat called pharyngeal jaws (Animal corner). Morays first latch onto their prey with the outer jaws. Then they actively use the pharyngeal jaws to pull it deeper down into the throat and stomach. They are the only fish using pharyngeal jaws to capture prey. When hunting by themselves they rely on their excellent sense of smell instead of their rather poor eyesight.
Moray is a fish with a dorsal fin that runs along the full length of its body (Animal network). They don‘t have pectoral or pelvic fins and swim in an undulating motion, pretty much like snakes. Morays don‘t have scales but thick skin with many cells secreting lots of mucus. In some species the mucus contains toxins. While sand-dwelling morays use the mucus to stabilize the sides of their burrows, eels such as the giant moray living in cracks and crevices in the reef might just glide through the habitat with more ease this way. Possibly, it helps the giant moray to stay clean. Divers can often observe cleaner wrasses and shrimps taking care of the set of teeth as well as the rest of the muscular bodies of giant morays.
This giant moray was filmed by Yoeri at the house reef of Wakatobi Dive Resort in Indonesia with a Panasonic GH5s in a housing of Nauticam and with lights of Archon. However, the species is widespread not only in the Indo-Pacific but all the way from the Red Sea and the eastern coast of Africa via Polynesia, the Pitcairn group and Hawaiian islands to the west. North to south, giant morays can be found from Japan to New Caledonia, Fiji and Australia. Giant morays live in lagoons and on the outer slopes of coral reefs. During the day, they mostly stay inside reef crevices between 1 and 50 meters deep.
Giant moray eel (Gymnothorax javanicus) reaches sexual maturity when they are around 2,5 years old. For mating, giant morays wrap their bodies around each other and release eggs and sperm simultaneously (Sea unseen). Morays as so many other ocean creatures are hermaphroditism. Some are sequential, meaning they change their sex over the time of their lives, and others are synchronous, having both reproductive organs. Courtship usually happens when water temperatures are high. After the larvae have hatched, it floats through the ocean for a year or so. As soon as the larvae are big enough, they swim down to the reef and hide there while slowly turning into the next generation of moray eels.
It clearly pays off to know about (marine) animal behaviour.
Take a Minute XLVI: Leaf scorpionfish (Taenianotus triacanthus)
„Take a Minute to Relax“ and observe another weird and wonderful creature hiding in the coral reefs: Leaf scorpionfish (Taenianotus triacanthus). The leaf scorpionfish, also called paperfish, is definitely the most elegant of all the ambush predators. Ambush predators, also called sit-and-wait predators, are carnivorous animals that get to their meals by stealth or by strategy rather than by speed or by strength.
Ambush predators sit and wait for prey, often from a concealed position and, in the case of our marine candidate here, concealing themselves by different methods of camouflage. Blending in has created some remarkable features, giving these creatures quite unique looks. As one would expect from animals specialised to suck their prey in, their heads and in particular their mouths are quite large in comparison to their overall body size. By opening their mouth quickly, they create a sucking motion strong enough to catch and swallow their prey in one bite.
So much on ambush predators in general, back to our little Leaf scorpionfish (Taenianotus triacanthus) in particular. It comes in many colour variations from black, red, yellow and white to pink, green, brown or ochre. It always works with dark or light mottling to match their surroundings or simply perfect their elegant and timeless disguise of an ambush predator.
Taenianotus triacanthus is amongst the smaller ones of the scorpionfishes, only up to 10 cm when fully grown. Its unusual shape lets it stand out: flattened body from side to side and tall as the sail-like dorsal fin, with 12 spines starting right behind the eyes, is lifted up most of the time. As you can see, there is a darker line going across its eyes to break up the outline. Sometimes this line is more spotted. Its dark pupils have a rim with yellow spots which continues as stripes into an area around the eyes where all leaf scorpionfish show a radiant pattern in various colours.
Taenianotus triacanthus has several small appendages to assist with blending in and sometimes even real algae or hydroids settle on its skin. The anal fin has an additional three spines and even though the venom of leafies is considerably weaker than the one of lionfish or stonefish, it should be avoided.
Same as with other ambush predators, swimming is not its strong point. Instead, leaf scorpionfish use their large pelvic fins to wedge themselves into position. Then they simply sit and wait until suitable prey, a small fish or crustacean, approaches. To look inconspicuous, leafies rock gently from side to side, pretending to be a dead leaf moved by the water. This camouflage is perfected by irregular brown to black (or white) blotches over their bodies. If they have to move, they tend to hop or walk on their pectoral fins. Once their prey is within striking range, it is sucked in by a sudden opening of the mouth.
Unlike other scorpionfishes their look is elegant and timeless, they can’t just change with the blink of an eye. Every 10 to 14 days leaf scorpionfish moults and this way can change its colour step by step over a longer time period. Pieces of old skin stay attached to the body and assist in the overall camouflage. Interestingly, some leafies match the colours of their surroundings quite perfectly, while others a clearly more flamboyant and, colourwise, stand out quite a bit. This does not seem to be a problem for their hunting technique. We have observed leafies staying in the same spot for years and not feeling the need to adjust their colour to match their surroundings.
Taenianotus triacanthus is widespread around the world. You can meet leafies from the east African coast and the Red Sea to the tropical Indo-Pacific, north to the Galapagos Islands, the Ryukyu Islands, Hawaii, and the coast of New South Wales. They can be found anywhere in tropical waters on coral reefs, from shallow water to a depth of 130 m. However, in Wakatobi where this footage was taken they preferred to hang out in between 2 and 7 metres.
The females produce eggs that are released into the water and then fertilized by a male. Afterwards, they float near the surface until they hatch.