Guestblog: Frogfish history

IMG_0737This is the second guestblog by Daniel Geary, resident marine biologist  and frogfish-enthusiast at Atmosphere Resort in Dauin, Philippines. You can read his first blog here. In this new guestblog Daniel explores the history of frogfish research and provides an introduction to a few common and not-so-common frogfish species.


There are many places across the globe where divers can see frogfish, but the Philippines (especially the Dauin area) is one of the best frogfish destinations of them all. I have personally seen thirteen species in this country, including 11 species here in Dauin. Sometimes we will see over 30 individuals on a single dive! It is not uncommon for some of the frogfish to stay on the same site for over a year, especially Giant Frogfish. Another great destination for frogfish is Indonesia, especially Lembeh, Ambon, and also some places in Komodo. Generally, if there is good muck diving, there is good potential for frogfish action. Australia also has some unique frogfish species, as well as the Caribbean, where there are a few places with reliable frogfish sightings.

Although frogfish are relatively well known critters to divers in the Indo-Pacific, this has not always been the case. Stories of frogfish and their accompanying drawings and sketches have existed for hundreds of years, with encounters spanning the globe. The first ever documented frogfish comes from Brazil. At some point before 1630, a drawing was given to the director of the Dutch West India Company. A woodcut was made from this drawing, and that woodcut was published in 1633. The first color drawing appeared in 1719, published by Louis Renard, an agent to King George I of England. He published a collection of color drawings of Indo-Pacific fish and other organisms and some of these represent the earliest published figures of Indo-Pacific frogfish. One was called Sambia or Loop-visch which translates directly to “walking fish.”

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First colour drawing of a frogfish – Louis Renard 1719

Albertus Seba and Philibert Commerson were two important scientists in the 1700s when it comes to frogfish. Seba believed frogfish were amphibians and tried very hard -incorrectly of course – to prove that they were the link between tadpoles and frogs, although anyone who has seen a baby frogfish knows this to be false. Even though he incorrectly identified a few nudibranchs as juvenile frogfish, he was still able to identify two species, the Hairy Frogfish (Antennarius striatus) and the Sargassumfish (Histrio histrio) during his studies. Commerson was the first scientist to focus solely on frogfish. He was a botanist and naturalist employed by the King of France and he described three species from Mauritius (Painted Frogfish – Antennarius pictus, Giant frogfish – Antennarius commerson, Hairy Frogfish – Antennarius striatus).

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Commerson’s drawing of the hairy frogfish – Antennarius striatus

There have been plenty of identification problems when it comes to frogfish, even today.  Frogfish colorations and patterns are highly variable, so it is nice to know people have been struggling with frogfish identification for hundreds of years. Albert Gunther, a scientist who attempted describe the different species of frogfish, said in 1861 that “[their] variability is so great, that scarcely two specimens will be found which are exactly alike…although I have not the slightest doubt that more than one-half of [the species] will prove to be individual varieties”. He listed over 30 species, but only 9 of those species are still accepted today. Since 1758 there have been over 165 species described and over 350 combinations of names. Currently there are around 50 accepted species, roughly one third of the total species described.

FROGFISH SPECIES PROFILES

Painted Frogfish – Antennarius pictus

This is the most abundant frogfish species in the Indo-Pacific. They can be identified by having 3 distinctive spots on their tail. They prefer to live near sponges, rocks, ropes, mooring blocks, and car tires. They can grow to a maximum size of around 15 cm.

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Painted frogfish (Antennarius pictus) with its typical three tail spots

Sargassumfish – Histrio histrio

This is the species with the largest distribution. They can be found in floating seaweed or debris as well as anchored seaweed and other marine plants. They can reach a maximum size of around 15 cm and are often sold in the marine aquarium trade.

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Sargassumfish (Histrio histrio), a surprisingly good swimmer that lives on floating seaweed

Psychedelic Frogfish – Histiophryne psychedelica

This is one of the rarest frogfish species. They are only found in Ambon, Indonesia at a handful of dive sites, usually at around 2-3m hidden in rock crevices or in coral rubble.

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“Snooted” picture of a psychedelic frogfish (Histiophryne psychedelica)

Giant Frogfish – Antennarius commerson

This is the biggest frogfish species, reaching lengths of more than 40 cm. They prefer to live on sponges and have two large spots on their tail, as well as lines coming from the eye and enlarged dorsal spines.

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Giant frogfish (Antennarius commerson) resting on a sponge. Note the two tail spots

Ocellated Frogfish – Nudiantennarius subteres

This frogfish species is the “newest” frogfish species. Originally thought to be a new species, it turns out this species is the previously described, relatively unknown “Deepwater Frogfish”, although the lure is incorrect in the original drawing. It was thought that the adults lived deep and only the juveniles were found in the shallows, but  adult mating pairs of this species have been seen at less than 10m depth. They grow to around 5 cm.

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Typical coloration of the Ocellated frogfish (Nudiantennarius subteres)

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Guestblog: Frogblogging – insights in the world of frogfishes

IMG_0737This month’s guestblog is written by Daniel Geary, the resident marine biologist at Atmosphere Resort in Dauin, Philippines. It’s safe to say that Daniel is very passionate AND knowledgeable about frogfishes. He’s been studying them for years in Dauin and even wrote (and teaches) a PADI speciality course on these awesome critters! In this blog he gives a taste of some of the many ways frogfish are fantastic and deserve a closer look.


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Longlure frogfish (Antennarius multiocellatus) from Florida

Frogfish. You have probably heard of them, and if you’re a diver you might have seen one or two before. You have definitely swam right past a few of them without knowing they were there. Although most of them have a face only a mother could love, behind this outer layer exists a well-adapted, expert fisherman with amazing camouflage capabilities. They are more than just a lazy, camouflaged blob that sometimes doesn’t change location for a year.

Frogfish are anglerfish, although they are what I call a shallow, less ugly version of anglerfish. They have a rod and a lure that they actively fish with when necessary. Their fins look like limbs that somewhat resemble those of a frog. They must inhale water though their mouth to then push it out of their gills which aids in locomotion. Frogfish are experts at changing color and can change color multiple times, usually to blend in with their surroundings. Normally a full color change takes about 2 weeks, but frogfish have been witnessed to change color in under ten seconds when disturbed by divers’ bubbles and needing to switch to a different coral.

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The same giant frogfish (Antennarius commersoni) changing colour in two weeks

There are around 50 species of frogfish, with a new species or two being described every few years. Frogfish can be found worldwide in tropical and subtropical waters (but not in the Mediterranean). Some species are only found at a handful of dive sites, others are only found in one country or continent. A handful of species are found in the majority of the warm water areas, but only the Sargassumfish is found worldwide. There have been a few occasions where Sargassumfish were found all the way up in the cold waters of Norway and Rhode Island – way out of their preferred habitat, but they live their lives floating in seaweed and/or other debris and are at the mercy of the ocean currents.

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Sargassum frogfish (Histrio histrio) often wash up on the shore of the Atmosphere housereef, when they do, they get released back into deeper water

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Painted frogfish (Antennarius pictus) using its lure to attract prey

Frogfish are ambush predators which is why they seem to be so lazy. The less they move, the better predators they can become due to algae, coral polyps, and any other organisms that use the frogfish as habitat. I call this being lazily efficient, or efficiently lazy. Frogfish will make minimal adjustments to their body positioning before they begin to lure prey, although sometimes the frogfish are so camouflaged that they don’t need to actively attract prey. Frogfish swallow their prey whole by opening their mouth and creating an instant vacuum since the volume of the mouth increases up to twelve times the original amount. This means frogfish can swallow their prey whole in six milliseconds. They feed on a variety of organisms, depending on where the frogfish lives. Generally they like small fish like cardinalfish, shrimps and crabs, and sometimes other frogfish. They can comfortably swallow prey that is their own size, and with a bit of effort they can swallow prey up to twice their size, although this can result in the death of the frogfish if the prey item is too large and gets stuck in their throat. Frogfish do not have many predators, but they are sometimes preyed on by moray eels, triggerfish, and lizardfish. Flounder will sometimes suck up juveniles from the sand and fishermen in the Philippines have been known to capture and eat Giant Frogfish.

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This giant frogfish (Antennarius commersoni) bit of more than it could chew and did not live to tell the tale. Photo taken at Apo Island

 

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Frogfish egg raft

Frogfish have been known to eat each other if they get too close, especially after failed mating attempts. A male will approach a female when she is bloated with eggs. He will do his best to show off for her, which includes expanding his fins to their maximum sizes, rapidly opening and closing his mouth, as well as violently shaking his body. At this point, the female either accepts him or tries to eat him. If accepted, he gets to stand next to the female, which is the frogfish equivalent of holding hands. Once he is ready to mate, he will start again with his flashy moves, but this time bouncing around the female. Sometimes he has to physically swim her off the substrate to mate, other times she is able to swim on her own. Once they are a meter or two above the substrate, the female releases her egg raft, causing her to spin rapidly. The male then fertilizes this egg raft, also spinning rapidly. Both the frogfish then return to the bottom as the eggs float off into the distance. The eggs will hatch a few days later and become tiny planktonic frogfish babies, which will continue to float for a month or two until they are big enough to settle in the substrate, change color, and begin their lives as adorable frogfish.

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A male (red) painted frogfish (Antennarius pictus) trying to convince the female (yellow) to mate

Stay tuned for more frogfish insights coming in December, where I’ll write about the history of frogfish research and describe a handful of frogfish species, including a potentially “new” species. Until then, keep an eye for frogfish on all your dives, especially if you’re in warm water.

Guest blog: Big brother is watching – Spying on the secret lives of endangered seahorses

Louw_CroppedIt’s time for a new guestblog, this one is by the amazing Louw Claassens. Louw is a South-African marine scientist at the Knysna Basin Project and a member of the IUCN Seahorse specialist group. She studies one of the world’s most endangered seahorses, part of her work involves studying their behaviour, which recently resulted in a very interesting publication (go check it out!). In this guestblog she gives you the most important findings of that paper and shares some fantastic video footage. Enjoy!


A big part of ecological research is based on observations – where do animals occur, what do they eat, what do they do. Some of these questions can be answered by using standard scientific methods e.g. a population survey can tell you where animals occur (although why is a whole other kettle of fish!). The tricky part sets in when you want to find out what an animal is doing. Conventionally, this entails going to the animal in question and watching it (sounds pretty simple, right?!). But it is here where observational effect (the act of observing has an effect on behaviour) and observational bias (researcher bias as to expected behaviour) creeps in.

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I spy with my little…GoPro? (Photo: Louw Claassens)

One of the 21st century solutions to these observational problems, is using cameras to study animals, and we are now even able to use cameras to study animals under water (thank goodness for relatively cheap action cameras such as GoPro’s!). Most fish research uses cameras to look at fish diversity, abundance, and habitat use – with limited work on actual fish behaviour. One of the reasons for this is probably owing to the highly mobile nature of most fish species.

So, is there a place for action cameras in fish behavioural research?

We focused on seahorses to answer this question. The conventional way to study seahorse behaviour entails getting in the water and watching the seahorse go about its business. Or, getting some seahorses and conducting observational research in the lab. The first method is problematic owing to two reasons: 1) Observer effect (the seahorse might act differently when you are watching it), and 2) seahorses move quite slowly most of the time, so detecting a behavioral pattern is quite difficult. Not even to mention the costs and time involved in doing this. The latter method might make sense, but it is well known that animal behaviour in captivity is rarely authentic.

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A very well camouflaged Knysna seahorse (Hippocampus capensis) (Photo: Louw Claassens)

Our aim was to test the efficacy of using video cameras to study the natural behaviour of a seahorse, and we had the perfect opportunity to do this! During a recent population survey of the endangered Knysna seahorse (Hippocampus capensis) in the Knysna estuary (South Africa) we found a stable population within a residential marina estate. The seahorses were found to use artificial Reno mattresses (wire cages filled with rocks). We had the seahorses, we had a relatively protected area to deploy cameras, and we had a sturdy structure to attach the cameras to.

In the first instance, we wanted to see if seahorse behaviour changed throughout the day e.g. between the morning, midday and afternoon. To add to this, we had an opportunity to see what happens to seahorse behaviour during the busy December holiday season. To do this, we used boat noise as a potential stressor (as occupancy of the residential marina estate increases from ~30 % to 100 % over the holiday period).

Video: Aggressive behaviour in the Knysna seahorse (Hippocampus capensis) – main action starts at 0:45.

But first we had to see if cameras successfully captured seahorse behaviour and if they could be used in behavioural assessments. We conducted a short trial period to test this, and found that 49 % of footage recorded contained seahorses. Using this data, we created an ethogram (a catalogue or table of all the different kinds of behaviour or activity observed in an animal) for H. capensis:

  • Feeding: the seahorse is actively searching for prey animals.
  • Irritation: identified by increased clicking and tail adjustments.
  • Moving from holdfast to holdfast: seahorse moves around without any feeding behaviour in-between.
  • Interaction: interaction behaviour can either be between a male and female as part of courting or between seahorses of the same sex and might entail aggression.
  • Stationary: seahorse remains completely still.

Video: Knysna seahorse (Hippocampus capensis) feeding

The next step was to deploy the cameras throughout the day (morning, midday and afternoon) and across the longer time periods (Pre-holiday, Holiday and Post-Holiday). To assess behaviour we used 10-min video sections as a sample and timed all observed behaviour for a single focal animal during the sample.

We recorded hours of footage, of which 57 hours contained suitable footage of seahorse behaviour. Seahorses spent 82 % of their time feeding and we noted courting behaviour exclusively in the morning. This courting behaviour entailed grasping of the female’s tail by the male in an attempt to position himself face to face with the female, followed by swaying movements. We also found that seahorses were more visible and fed more during the morning. There were no differences between the behaviour of males and females.

Graphic footage! Video of a cormorant catching a seahorse (H. capensis)

We observed quite a few cuttlefish, rays and cormorants, but only noted predation by the latter (check out the video above!). Seahorses were also observed happily living side by side with octopus, although octopus are known to eat seahorses in Australia. We also noted some other curious fish, like our temperate butterfly fish (Chaetodon marleyi) (video below) – can you spot the seahorse?

A cold water butterfly fish (Chaetodon marleyi) checking out Louw’s GoPro setup

When we looked at behavioural changes across the longer-term periods, we noted a decrease in visibility and feeding activity of the focal seahorse, with an increase in irritation behaviour, during the holiday period. No courting behaviour was noted during the holiday period – which is a bit concerning, seeing that this species breeding season is from September to March.  Feeding activity and seahorse visibility increased again during the post-holiday period.

So, what does all this tell us? Action cameras are pretty useful in studying natural behaviour of seahorses. Recorded footage can be watched on fast-forward mode which enables a clear view of the behavioural pattern of the animal (something that is quite difficult to see whilst diving, as these guys move so slowly). For H. capensis, it was the first time that natural behaviour was studied, and we gained some valuable information with regards to feeding and interaction behaviour. In addition, it seems that boat noise has a negative effect on the natural behaviour of this species – an aspect which does need further research (preferably, a controlled experimental approach is needed here, to control the vast number of confounding factors that might have played a role!). The use of cameras in natural seagrass habitat also needs to be tested, as visibility might be problematic in dense vegetation.

In the past, the world of underwater research was exclusively meant for the eyes of the researcher/diver. Now, we are able to bring what we experience to the surface and to the lay person. And perhaps the real power of doing this is to create and instill that love and passion for the underwater world that all divers and water lovers have, in all people. I mean, who cannot fall in love with two seahorses doing their morning courting dance?

The secret sex lives of seahorses: mating dance of the Knysna seahorse

Photo Story: Hidden Treasures Amongst the Muck – Guestblog by Luke Gordon

Luke

Time to kick of December with a new guestblog, this one by none other than my good friend and science hobbit Luke Gordon! Luke is a very talented photographer whom I’ve been having ocean adventures with for many years. He is currently based in Canada, but continues his photography work there. Increasingly he uses his art as more than mere beautiful pictures, but instead uses it to tell important stories about ocean conservation issues. You really should have a look at his site, but until you do, here is an introduction to his most recent story.


Diverting the majority of my photography work towards conservation photo journalism has been an incredibly rewarding experience so far. I am very lucky to have met various people & organisations over the years which has now allowed me to get up close and personal to certain issues such as, establishing sustainable fisheries in Fiji, and now looking at salmon enhancement projects in British Columbia, (and of course Maarten, the first person worldwide to be dedicating a PhD solely to the soft sediment world & the creatures living there).

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A ‘barren habitat’ could not be further from the truth, life here as evolved in the most intricate of ways, mimicry is the name of the game on the muck slopes. Species such as this Giant Frogfish (Antennarius commersoni) have evolved near perfect mimicry of sponges as they sit in wait for unsuspecting prey.

The critters of the muck for me, and I am sure for the large majority of photographers who have experienced this world, are the perfect definition of evolution and beauty of the natural world. Everything about this underwater paradise captivates me. From the story of its discovery to the most elusive of its organisms, muck is a magical world.

Let us start at the discovery, muck was discovered by chance by Bob Halstead, a man credited for pioneering the liveaboard industry and diving in Papua New Guinea, the story goes that whilst on a liveaboard in PNG the boat had moored up in Milne Bay for the night where it was calm, Bob Halstead still wanted to go for a night dive and despite the attempted dissuasion from local dive masters they went for a dive right beneath the boat. As the dive masters had predicted the bottom was just endless sand (soft sediment) from where the name of ‘muck’ originated, however the dive masters were wrong about one thing, and that is that there was no life down there, quite the contrary, what they found were creatures that looked like extra terrestrials, creatures that even the like had never been seen before, muck diving was born.

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A tiny, recently settled juvenile Ornate Ghost Pipefish hangs above a crinoid. Even though this little critter doesn’t know it, the large ‘creature’ in the background is paving the way forward for future research into this unique habitat.

This all happened in the 1980’s, the diving community took a while to catch on, but boy has it caught on, muck diving now is a booming industry which supports thousands of people across Southeast Asia, as Maarten’s research will soon shed more light on. Divers and photographers (and now researchers of course) alike will travel half way across the world just to glimpse these weird and wonderful creatures, and these creatures are not behemoths like the African mammals, no, they are tiny critters which have evolved perfect mimicry and other adaptions to survive in a sandy desert, perfect photography subjects.

So how does a photo story fit into all of this?

Luckily enough for me (well not that lucky, I am referred to as a science hobbit by Mr. De Brauwer, yes, there is an earlier blog about this!) I was able to help Maarten with a large proportion of his fieldwork in North Sulawesi & Bali, Indonesia and on Negros, The Philippines. This gave me a fantastic opportunity to tell a story about this industry and now, the research being conducted. Currently it is quite staggering how many divers travel to muck locations around the world and it is equally staggering how little we know about the ecology, abundances and diversities of these creatures and the threats they face. This is a huge problem, as I have already mentioned thousands of people now rely on the jobs created by the industry and the money the industry brings into countries such as Indonesia and The Philippines. On top of this there is also no baseline data outlining the abundances and diversities of the creatures that have traditionally existed in these habitats, we have no way of gauging how these habitats are responding to the huge increase of direct and indirect anthropogenic pressures.

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Arjay Salac is a dive master and one of the figure heads for Atmosphere Resort & Spa’s dive centre. Arjay is from a family of fishermen who live on the adjacent plot of land to the resort, after initially being employed as a landscaper when the resort first opened Arjay took a keen interest in the dive world going on. Enthusiasm and work ethic allowed him to move into a boat crewman position. Through continued excellence in the role he was offered the opportunity of being put through the resorts PADI dive master scholarship. Needless to say Arjay excelled and six years later is now one of the most respected dive guides in the area, eagle eyes are a description which fit Arjay perfectly.

This story is a way for everybody, diver or not, to understand how and why these organisms are so special, the pressures they face and how these tiny organisms have changed the lives of so many people across coastlines in Southeast Asia, and now, what research is being conducted to answer the many, many unanswered questions we have.

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A Juvenile frogfish is measured after being caught in one of the S.M.U.R.F‘s. Frogfish, like many of the cryptobenthic organisms, are still unknown to science, this particular individual is most likely a new, undescribed species of frogfish (Antennatus sp.). Note from Maarten: this animal was returned to the ocean alive and well

This blog shows a few small extracts of the story, please visit my site for the full photographic story.

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The future generation of instructors, dive masters and dive guides.