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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Marine biodiversity in Oman: Mini-blog 2 – Meet the team

In the previous blog I wrote how I joined a great team of researchers to study fish diversity in Oman. The scientists I’m working with are experts in their fields, and form a very complimentary group, perfect to be studying fish diversity with. It’s fantastic to be collaborating with them, especially since this kind of work is new to me, which means I am learning loads at the moment! So it’s only fair to introduce the people that are really driving this trip.

Amanda

Ms. Amanda Hay: Amanda is Acting Ichthyology Collection Manager at the Australian Museum. She is a taxonomy expert, specialised in larval fishes. While she considers herself a jack-of-all-trades, she is the most organised member of the team who makes sure all the fish are named and catalogued properly.

 

Chris

Dr. Chris Goatley: Chris is a postdoctoral research fellow at University of New England who specialises in reef fish ecology. In particular, Chris is interested in the ecology of the smallest coral reef fishes, including gobies and blennies. He is particularly interested in the roles of these small fishes in maintaining coral reef food webs.

 

DarrenDr. Darren Coker:  Darren is a Research Scientist in the Red Sea Research Center and Saudi Aramco-KAUST center for Marine Environmental Observations at King Abdullah University of Science and Technology in Saudi Arabia. Here he focuses on reef fish communities along environmental gradients and how local and global stresses influence fish groups that are important to reef health.

Alyssa MarshellDr. Alyssa Marshell: Alyssa is an Assistant Professor in the College of Agricultural and Marine Sciences at Sultan Qaboos University. She is on of the lead investigators on the DFAT CAAR grant that funds this research project. Alyssa is an expert in marine and spatial ecology, with particular interests in the movement and behaviour of herbivorous reef fishes.

JoeyDr. Joey DiBattista: Joey is the new Curator of Ichthyology at the Australian Museum and standing member of the TrEnD Lab at Curtin University. Joey is the other lead investigator on this research project. His name might sound familiar if you follow this blog, since he has written a very interesting guest blog in the past. Joey is interested in developing next generation-sequencing tools to aid in  fisheries management. His new position role at the museum will allow him to build up genetic “barcode” libraries for fishes across Australia.

These are not the only team members working on this project, other researchers involved include remote marine field specialist Tane Sinclair-Taylor, PhD student Mark Priest, and Director of the Red Sea Research Center at KAUST – Professor Michael Berumen. Their contribution is at least as important as the other members, but they are unfortunately not close enough at the moment to hassle them for info.

Lastly, the newest, honorary member of the team is our Musandam captain Ali! Ali owns  Ras Mudandam Diver, the dive centre that was taking us out for our work here. He’s been an absolute legend, and if you’re considering diving here, you should definitely look him up!

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Captain Ali

 

 

Leafy seadragons: Australia’s favourite fish

In a recent poll organised by the Australian Society for Fish Biology and Lateral Magazine, the Leafy Seadragon (Phycodurus eques) was voted as Australia’s favourite fish. This exquisite critter definitely deserves its place at the top, to celebrate it amazingness I wrote a blog about it. This blog appeared originally as an article in Lateral Magazine, you can find the original version here.


According to the popular stereotype, marine biologists spend their careers diving on colourful coral reefs, cuddling dolphins, and wrestling sharks. Unfortunately, the truth is a lot more mundane; we are more likely to spend our days diving into data analyses, cuddling too many cups of coffee, and wrestling grant proposals.

But sometimes we get lucky enough to work with animals that exceed the wildest stereotypes. Studying marine life is always exciting, but some animals are so unique they just stop you in your tracks; they make you thank your lucky stars for not listening to your mother when she said ‘marine biologist’ was not a real job.

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Two leafy seadragons. Photo credit: David Harasti

For me, the ultimate awe-inspiring fish is the leafy seadragon (Phycodurus eques). “Leafies” only occur in temperate waters off southern Australia, and they are, to say the very least, unique animals — the kind that makes you wonder whether evolution had a stroke of brilliance or just a stroke. Seadragons belong to the Syngnathidae family, which also includes seahorses and pipefishes. Even in a family that is known for their oddly-shaped members, leafies stand out big-time.

These beautiful fish have the head of a seahorse and the body of a seaweed, with flamboyant leaf-like protrusions that wouldn’t look out of place at the Carnival in Rio de Janeiro. Leafy seadragons defy the idea of what a fish should look like.

Maybe that is why they are so popular with fish enthusiasts all over the world. Scuba divers fly halfway across the globe to dive in the cold waters off southern Australia, hoping to catch a glimpse of them. In the few public aquaria that display them, including Melbourne Aquarium, leafies are one of the absolute crowd-pleasers. For fish-lovers, this Australian endemic fish is at least as iconic as kangaroos or koalas.

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Leafy seadragon. Photo credit: Tony Brown

Despite their popularity, we know surprisingly little about leafy seadragons. Adult leafies are one of the largest members of the Syngnathidae family, with adults measuring up to 35cm. Like seahorses, male seadragons carry their mating partner’s fertilised eggs; unlike seahorses, they do not have a pouch. Instead, females lay their eggs on the underside of the male’s tail, where they remain until hatching.

Leafy seadragons depend on kelp and seagrass beds as their habitat, where they blend in supremely well to avoid predators. Unfortunately, these habitats are in decline all over the world, including in Australia, caused by coastal development and potentially climate change. As a result, seadragon population numbers are decreasing, although the species is currently not considered to be endangered.

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Admiring a Weedy seadragon, a close cousin of the Leafy seadragon. Photo credit: Greg Lecoeur

One would assume that the decreasing population numbers of a unique Australian emblem would inspire multitudes of researchers to study it. Strangely, this is not the case. A search of the scientific literature suggests that nobody has studied them in the wild for almost a decade. This lack of research on evolutionary distinct marine critters is unfortunately not unique to seadragons. It extends to many other species that do not fit in the ‘food’, ‘danger’, or ‘Pixar-famous’ categories in which landlubbers like to divide marine life. If so little attention is paid to the struggles of Australia’s most recognisable and charismatic fish, then what hope do other species have?

Time will tell what the future holds for the leafy seadragon. I, for one, am doing what I can to ensure generations after ours will continue to have their minds boggled by this incredible animal. If you care about seadragons, one way to help is to join citizen science projects such as iNaturalist or Seagrass Spotter. These projects collect observations from divers and snorkellers, directly helping scientists better understand and protect these animals and their habitats.


A short note about this blog: Two weeks after the poll I was awarded a research grant by the Sea World Research and Rescue Foundation to study the seadragons using eDNA. Hopefully the results that will come out of this research will help to better understand and protect these beautiful fishes.