New publication: Flash photography impacts on fish – To flash or not to flash?

The final paper of my PhD thesis has just been published online in the journal Scientific Reports. The paper, titled “Behavioural and pathomorphological impacts of flash photography on benthic fishes” explains the effects of typical diver behaviour while photographing small critters such as seahorses or frogfishes.

The paper itself can be a tad technical, so with the help of two co-authors (Dr. Ben Saunders and Tanika Shalders), I wrote this summary of the research, which was published first at The Conversation (original article here).


We all enjoy watching animals, whether they’re our own pets, birds in the garden, or elephants on a safari during our holidays. People take pictures during many of these wildlife encounters, but not all of these photographic episodes are harmless.

There is no shortage of stories where the quest for the perfect animal picture results in wildlife harassment. Just taking photos is believed to cause harm in some cases – flash photography is banned in many aquariums as a result.

But it’s not always clear how bright camera flashes affect eyes that are so different from our own. Our latest research, published in Nature Scientific Reports, shows that flash photography does not damage the eyes of seahorses, but touching seahorses and other fish can alter their behaviour.

Look but don’t touch

In the ocean it is often easier to get close to your subject than on land. Slow-moving species such as seahorses rely on camouflage rather than flight responses. This makes it very easy for divers to approach within touching distance of the animals.

Previous research has shown that many divers cannot resist touching animals to encourage them to move so as to get a better shot. Additionally, the high-powered strobes used by keen underwater photographers frequently raise questions about the welfare of the animal being photographed. Do they cause eye damage or even blindness?

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Does flash harm fishes? Photo: Luke Gordon

Aquariums all around the world have taken well-meaning precautionary action. Most of us will have seen the signs that prohibit the use of flash photography.

Similarly, a variety of guidelines and laws exist in the scuba-diving community. In the United Kingdom, flash photography is prohibited around seahorses. Dive centres around the world have guidelines that include prohibiting flash or limiting the number of flashes per fish.

While all these guidelines are well-intended, none are based on scientific research. Proof of any damage is lacking. Our research investigated the effects of flash photography on slow-moving fish using three different experiments.

What our research found

During the first experiment we tested how different fish react to the typical behaviour of scuba-diving photographers. The results showed very clearly that touching has a very strong effect on seahorses, frogfishes and ghost pipefishes. The fish moved much more, either by turning away from the diver, or by swimming away to escape the poorly behaving divers. Flash photography, on the other hand, had no more effect than the presence of a diver simply watching the fishes.

For slow-moving fishes, every extra movement they make means a huge expense of energy. In the wild, seahorses need to hunt almost non-stop due to their primitive digestive system, so frequent interruptions by divers could lead to chronic stress or malnutrition.

The goal of the second experiment was to test how seahorses react to flash without humans present. To do this we kept 36 West Australian seahorses (Hippocampus subelongatus) in the aquarium facility at Curtin University. During the experiment we fed the seahorses with artemia (“sea monkeys”) and tested for changes in their behaviour, including how successful seahorses were at catching their prey while being flashed with underwater camera strobes.

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The aquaria were the seahorses were housed during the experiment

An important caveat to this experiment: the underwater strobes we used were much stronger than the flashes of normal cameras or phones. The strobes were used at maximum strength, which is not usually done while photographing small animals at close range. So our results represent a worst-case scenario that is unlikely to happen in the real world.

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West Australian seahorses (Hippocampus subelongatus) in their aquarium at Curtin University

The conclusive, yet somewhat surprising, result of this experiment was that even the highest flash treatment did not affect the feeding success of the seahorses. “Unflashed” seahorses spent just as much time hunting and catching prey as the flashed seahorses. These results are important, as they show that flashing a seahorse is not likely to change the short-term hunting success (or food intake) of seahorses.

We only observed a difference in the highest flash treatment (four flashes per minute, for ten minutes). Seahorses in this group spent less time resting and sometimes showed “startled” reactions. These reactions looked like the start of an escape reaction, but since the seahorses were in an aquarium, escape was impossible. In the ocean or a large aquarium seahorses would simply move away, which would end the disturbance.

Our last experiment tested if seahorses indeed “go blind” by being exposed to strong flashes. In scientific lingo: we tested if flash photography caused any “pathomorphological” impacts. To do this we euthanised (following strict ethical protocols) some of the unflashed and highly flashed seahorses from the previous experiments. The eyes of the seahorses were then investigated to look for any potential damage.

The results? We found no effects in any of the variables we tested. After more than 4,600 flashes, we can confidently say that the seahorses in our experiments suffered no negative consequences to their visual system.

What this means for scuba divers

A potential explanation as to why flash has no negative impact is the ripple effect caused by sunlight focusing through waves or wavelets on a sunny day. These bands of light are of a very short duration, but very high intensity (up to 100 times stronger than without the ripple effect). Fish living in such conditions would have evolved to deal with such rapidly changing light conditions.

This of course raises the question: would our results be the same for deep-water species? That’s a question for another study, perhaps.

So what does this mean for aquariums and scuba diving? We really should focus on not touching animals, rather than worrying about the flash.

Flash photography does not make seahorses blind or stop them from catching their prey. The strobes we used had a higher intensity than those usually used by aquarium visitors or divers, so it is highly unlikely that normal flashes will cause any damage. Touching, on the other hand, has a big effect on the well-being of marine life, so scuba divers should always keep their hands to themselves.

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Look, take pictures, but don’t touch!


NOTE: I realise that this is a controversial topic in underwater photography. If you have relevant questions, comments, or thoughts you want to share, feel free to add them in the comment section below. If you are interested, I would highly advise you to read the original research paper via this link. The paper is open access, so anyone can read and download it. If you have specific questions about the paper, you can always contact me via email here.

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New publication: How well do divers, cameras, and critters play together on the sand?

A new paper from my PhD research was published two weeks ago. This paper is the first of two papers that investigate the impacts of scuba divers. The title of this one is: “Time to stop mucking around? Impacts of underwater photography on cryptobenthic fauna found in soft sediment habitats” and was published in the Journal of Environmental Management. In the paper I describe how divers behaved while interacting with critters on muck dive sites and coral reefs.

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Underwater photography is fun, but what are the impacts? (Photo: Luke Gordon)

First a bit of context to this particular piece of research. It is well known that divers can cause serious damage to coral reefs, for example by accidentally kicking down coral with their fins, dragging equipment over the fragile bottom, or even breaking off bits of coral as a souvenir. We also know that wildlife photographers (under water and at the surface) can sometimes get carried away in their quest for the perfect picture, and show some very unethical behaviour while doing so. I have written about this before on this blog, but the recent story of yet another wildlife photography winner that was disqualified shows just how common this problem can be.

The goal of my research was to investigate how diver behaviour changes when divers are close to critters, if there is a difference between photographers / non-photographers, and how this changes on the sand versus coral reefs. Importantly, my goal was NOT to investigate if muck diving is a bad thing, or if photography should be banned. Ultimately, what this paper aims to achieve, is to help improve the sustainability of dive tourism.

I had some good fun observing divers in Indonesia and the Philippines during the fieldwork for this research. Divers were not told what research I was doing, to make sure they did not change their behaviour. Instead I explained that I was investigating the habitat requirements of little critters. This meant I had to pretend to be very interested in the bottom, while cheekily observing what divers were up to. To the point where all my notes had to be coded, so divers could not accidentally read what I was doing either.

So I was basically doing university-approved spying on people…the kind of things you end up doing for science 😉 In case  you were worried, all divers were informed of the real purpose of the research afterwards, and were asked for permission to use the (anonymous) data I collected.

The results of the research mostly confirmed what I expected and won’t come as a surprise to people who often go muck diving. When divers were close to critters (either just watching or taking pictures), they caused more impacts than when diving around normally.  During these “critter interactions”, divers touched the bottom three times as much than when they were not close to critters. During these interactions, divers that were taking pictures touched the bottom much more than the divers that were just watching marine life, or showing it to their buddies.

 

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Luke photographing like a pro: great buoyancy control, no equipment dragging over the bottom, and touching nothing except his camera

Divers on coral reefs had much less contact with the bottom than divers on muck dive sites, until they started observing or photographing critters. Once divers were near small marine life, they touched the bottom just as much on corals as on sand. Basically, divers pay attention not to damage coral reefs, until they get distracted by an interesting little critter.

Using a camera underwater caused some clear impacts. Compact camera users caused more damage than divers without a camera, or those with a dSLR camera. All camera users touched the bottom more often than non-camera users. Finally, divers with a camera spent much more time interacting with critters than divers without a camera.

Picture1Finally, throughout this study, I very frequently  observed divers touching marine life. Despite the fact that every dive training organisation teaches people not to touch anything underwater, touching animals seems to be a common thing while observing and photographing critters. Sometimes this touching is limited to a minor “prod”, but at its worst, divers can rip of arms of feather stars, smack fish around (you read that correctly!) or crush frogfish under big cameras. It is clear that this cannot be the goal of muck diving.

How can we use these results to improve the sustainability of dive tourism? These three guidelines could already make a big difference:

  1. Better education for divers and dive guides on how unethical behaviour impacts marine life. At the very least during briefings, but ideally using programs such as Green Fins or by incorporating it in diver training.
  2. Developing a (region-specific) code of conduct that is supported by all local stakeholders. This would include: dive centre operators, dive professionals, local government, training agencies, NGOs, etc.
  3. Increasing awareness of the impacts of wildlife photography on a global scale. This can only be achieved when the big players get involved. By this I mean not only organising committees of photography competitions, but also dive magazines, dive expos, wildlife magazines like National Geographic,… If all these organisations would send a clear signal to no longer publish pictures that were clearly the result of wildlife manipulation, keen divers would be far less likely to try and do it themselves.

In conclusion: muck diving and underwater critter-interactions have clear impacts, but it is possible to do something about it. The most important thing to start with is changing the mentality of quite a few divers who seem to think that their pictures are worth more than the damage they might cause to marine life.

PS: The paper is behind a paywall, but if you want to read it, please contact me via email or in a personal message on any social media (instagram, twitter, researchgate)

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

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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.

Fluo time

If this isn’t the first time you’ve read this blog, you probably know I am interested in the phenomenon of biofluorescence. I’ve previously talked written about what it is and what it might be used for. In the near future I’ll be tell you all about the details what I was actually doing. But I realized I haven’t shared any pictures recently that show just how beautiful and otherworldly it can be. So here is a random selection of fluo shots I took over the last two years. Enjoy!

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A bubble snail (Hydatina physis) photographed in Lembeh Strait, Indonesia

 

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Thorny seahorse (Hippocampus histrix) in Bima Bay, Indonesia

 

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West Australian Seahorse (Hippocampus subelongatus) in Perth, Australia

 

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Amazing coral in Raja Ampat, Indonesia

 

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Reptilian Snake Eel (Brachysomophis henshawi) in Amed, Indonesia

 

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Lizardfish (Synodus sp.) in Lembeh Strait, Indonesia

 

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Cockatoo Waspfish (Ablabys sp.) in Lembeh Strait, Indonesia

 

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Sea spider (Pycnogonid sp.) in Tulamben, Indonesia

 

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Painted frogfish (Antennarius pictus) in Lembeh Strait, Indonesia

 

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Juvenile Painted frogfish (Antennarius pictus) in Dauin, Philippines)

 

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Barred moray (Echidna polyzona) in Nusa Kode, Indonesia