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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Chasing the seadragon

dragon sign_mirrorOne month ago I realised one of my absolute critter dreams. I got to see Leafy Seadragons (Phycodurus eques) in the wild!  We had to travel to southern West Australia to find them. An area which is absolutely stunning and worth checking out, even if it didn’t have dragons. Since it was so much fun, I decided to share some of the highlights of the trip with you. Get ready for lots of pictures and start checking your calendar when you can go dragon hunting yourself!

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Dragon hunting in Bremer Bay and Cape Le Grand (Western Australia)

We started in Bremer Bay, a sleepy little town that only really gets busy in summer tourist season. Since we got there well before high season, we practically had the town (and more importantly the ocean) to ourselves. Before we even got to hunt for dragons, we explored some of the many beaches and oh my, was that worth it!

Beach view

Banky Beach

Tanika clifwalk

Climbing down to Banky Beach

Surfing native dog beach

Surfers at Native Dog Beach

Obviously our main goal was to find seadragons, preferably Leafy Seadragons. So we decided to go for a dive with Craig from Bremer Bay Dive. Craig is known as the expert to find dragons and knows the area like the back of his hand. Weather conditions were not ideal and unfortunately we only had one chance for a boat dive, so the stakes were high when we set out on a blustery morning.

Bremer Bay faces the Southern Ocean (the one around Antarctica) so the water tends to be on the chilly side. On the bright side, the water is a LOT clearer than what I have gotten used to in Perth. An average day will often have more than 20m visibility and I have been told it gets much better than this. Just dropping in and enjoying the views of the rocky reefs covered in kelp and schooling fish is worth diving here.

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Good conditions for dragon searching

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A Western Blue Devil (Paraplesiops sinclairi)

Now this might be obvious, especially for someone who studies cryptic critters for a living, but seadragons have some pretty damn good camouflage! 30 minutes into the dive we still hadn’t caught as much as a glimpse of one. I was still enjoying myself and I know better than most that the ocean is not a zoo. But I also realised that with the bad weather coming in, this was likely to be our only chance of seeing a Leafy Seadragon.

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The beautiful Leafy Seadragon (Phycodurus eques)

So when a few minutes later Craig enthusiastically pointed out a dragon, I was more than a little bit excited. It’s hard to describe just how amazing these animals are, or how I overwhelmed I felt to actually get to see one. But I’m getting goosebumps just writing this and thinking about the dive. Leafy Seadragons are without a doubt one of the most outlandish, beautiful and downright weird fish that roam the seas, and I count my lucky stars that I got to see them underwater.

Having fulfilled our Leafy Seadragon mission, we relaxed a few more days in Bremer Bay, hoping for the weather to clear before driving to Cape Le Grand National Park in Esperance. The area is known for it’s stunning beaches, great hikes, and outstanding marine life.

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Lucky Bay, Cape Le Grand National Park

We camped in Lucky Bay, while we were not very lucky with the weather (thunderstorms and tents are not the best combination), the bay itself is gorgeous. If you’ve ever seen a picture of kangaroo lounging on a white sand beach with turquoise waters, chances are very high it was taking in Lucky Bay (see below). More interesting for us is that you can also dive right off the beach, and that dragons are rumored to roam the waters.

Despite the less than ideal conditions, we decided to give it a go and hope for the best. The rocky dive site is surrounded by vast seagrass meadows, which make an ideal habitat for the Leafy Seadragon’s cousin; the Weedy Seadragon (Phyllopteryx taeniolatus). Weedies have less frills, and are a bit more colourful than Leafies. They also seem to be more common, and are found higher up the Australian coast than Leafies. We don’t know much more about them, but their preferred habitats are disappearing, which is cause for concern.

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Tanika watching a Weedy Seadragon (Phyllopteryx taeniolatus)

Initially we started looking for Leafies (which are sometimes present at the site) near the rocks covered with kelp, but the swelly conditions really weren’t helping. Once we changed our focus to the seagrass instead, it did not take us very long before we found two beautiful Weedy Seadragons. It was interesting to see that these Weedies were much more green in colour compared to the ones I’d seen before in Perth and Sydney. Perhaps an adaption to the high seagrass cover in the area? Food for thought!

The day after, it was already time to head back to Perth, although I would have loved to stay around much longer (even with the crappy weather). I definitely hope I’ll make it back there soon, not just to chase more dragons. There is more to do in the areas than just diving and snorkeling. Next time I’m definitely bringing a surfboard and my hiking shoes. Most of all, I’ll make sure to have more than just a week to do both spots.

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Beach walks, not a bad way to spend your time between dives

If you’ve made it this far in this blog, well done! As a reward I can offer you some more pictures of the trip, enjoy! 🙂

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Craig the dragon-chaser and a male Leafy Seadragon (Phycodurus eques)

 

Coastal flowers

Bremer Bay flora

Tanika bushwalk

Heading to a hidden beach

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Wandering the beach in Bremer Bay

Dragon gate

Fancy seadragon gate

 

 

 

 

 

Marine biodiversity in Oman: Mini-blog 3 – Workshop time

The Oman fish biodiversity trip I am currently doing is nearly over. We spent the last days in a workshop at the Sultan Qaboos University in Muscat. The workshop focus was on “Bridging the gap between marine resource managers and research institutions in Oman and Australia”. Besides our team, the workshop was attended by Omani researchers and government officials, international researchers working in the region, and even by marine students from the university.

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Participants to the workshop at Sultan Qaboos University

With such a varied group of attending researchers and presenters, talks were bound to be interesting and go beyond the work I am familiar with. The first day focused on seas around Oman, its diversity and natural history. Since this was my first visit to Oman and I know very little about its marine life, there was a lot of interesting new information to absorb.

The Omani seas are fascinating for many reasons, but one of the things that really stuck with me was how big the environmental differences are in a relatively small area. The north of Oman has seas that get very hot, with a high salinity and a very different fauna and flora than the southern areas. The south of Oman has coral reefs, but also has a strong cold upwelling each summer. This upwelling is so strong that temporary kelp forests grow here in summer! I did not get to dive there this trip and the kelp has already disappeared this time of the year, but it would be fascinating to come back and dive in the Salalah area.

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Hussein Al Masroori talks about designing solutions to reduce ghost fishing by lost fish traps

The second day of the workshop moved from natural history to new monitoring techniques, and explored some of the regions nearby Oman. There was a thought-provoking (but sad) talk about the heavy impact of coral bleaching in the Arabian Gulf. Water temperatures in the summer of 2017 reached up to 36°C, and some areas lost more than 90% of coral cover! Our team members also presented some of their personal work, Joey talked about eDNA, Darren about monitoring biodiversity in the Red Sea, and Chris talked about how cryptobenthic fishes could be used a sensitive measure of changes in reef health.

In an interesting discussion afterwards, it became very clear that collaborating across different countries is more effective than just working as a loner. When experts in certain fields can share their work and skills with researchers that may not have the infrastructure or cannot get the training in the country they work, everyone benefits. Local researchers often have a very extensive knowledge and valuable insights that visiting researchers just don’t have. As visitors, we can offer a new perspective and stimulate new ideas to help push the boundaries of knowledge.

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Sultan Qaboos University. Photo source: www.squ.edu.om

People like Joey and Alyssa, who stimulate these kind of collaborations, are the ones that (in my humble opinion) will make the biggest difference to marine science. Not just to improve our understanding of the ocean, but also to improve how we can sustainable use the ocean, or protect the areas and species that need it most.

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