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 ūüėČ 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)

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New publication: Finding the species that make a muck diver tick

Now that my PhD thesis has been submitted, it is time to start blogging again! In the very near future I will write a new blog about this whole PhD-writing experience, but for now I will tell you about a new paper that has been published recently in the scientific journal Ocean and Coastal Management.

The paper, “Known unknowns: Conservation and research priorities for soft sediment fauna that supports a valuable scuba diving industry“, describes which species are most important to muck dive tourism, and how much research and conservation work has been done on them. I investigated this using a specific method that is pretty new and has not been used in conservation work until now.

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Who doesn’t like a frogfish (Antennarius pictus)?

Since these the method and the results will be of interest to different people, this blog is split in two parts:

  1. How did I do the research?
  2. What are the results?

If you are a scuba diver, a dive professional, a travel agent or otherwise mostly interested in the cute animals, it’s completely fine to head straight to number two (even though you will be missing out). If you are a resource manager, work for an NGO, are interested in marketing, or conduct research on flagship species, definitely read the first part of this blog as well!

First section: the Best – Worst Scaling method and why everyone should start using it

wwf-logoIt is important to first think about why anyone would care about which species are important to muck dive tourism, or any kind of tourism by extension. The obvious answer would be “marketing”, if you know which species attract the tourists, you can use them in your advertising and that way attract more tourists. If that is too capitalistic for you, remember that dive tourism provides (mostly) sustainable incomes to thousands of people around the world. But there is more, people might not visit a destination, but still care very deeply about certain species. This principle has been used (very successfully) by many conservation organisations to set up fundraising campaigns. The best known example is probably the World Wildlife Fund, which uses the panda bear as a logo, even if they are trying to protect many more species.

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Blue ringed octopus (Hapalochlaena sp.) are popular with divers, maybe because of the cuteness combined with its deadly bite?

With that in mind, how do you find out which are the animals that people care about? You can obviously just ask people what they like, get them to make a list of top 5 animals, rank a number of animals in preferred order, give scores to certain animals, etc. But there are some serious problems with most of these methods such as:

  • They are not always reliable, since some people will be consistently more or less positive, or have cultural biases, throwing off your scaling
  • They can be very labour-intensive (=expensive) to properly design and collect data on
  • Statistical analyses of the results are usually very hard to get right
  • It is very difficult to say how the preferences vary between different groups of people (male-female, age, nationality, etc.)

To overcome these issues, we used the “Best-Worst scaling method” and compared it to a traditional survey. This method has been around for a few years, but is mostly used in food marketing (wine!) and patient care in medical research. The big benefit of Best-Worst scaling is that doing the stats is really easy, and without too much extra effort you can also easily interpret how different groups have different preferences.

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Flamboyant cuttlefish (Metasepia pfefferi) might not be popular with researchers, but divers love them!

Without going into too much detail, the basic design of Best-Worst scaling is that you ask people what they would like MOST and LEAST from a fixed set of animals (or any other thing you are investigating). There are plenty of online platforms (we used Qualtrics) that allow you to design this kind of question, so it’s quick, easy and cheap. Getting results is as simple as subtracting the amount of times an animal was picked as most preferred and the number of times it was least preferred.

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Example of a Best-Worst Scaling question

The reason I am describing this method here, is that it is just not known enough in the conservation, or even tourism world. It has the potential to allow all kinds of organisations with limited funding (NGOs, marine parks, or even dive centers) to investigate why people would visit / where they will go / what they care about. Which, eventually, might lead to more research and conservation on those species.

Second section: Which species drive muck dive tourism?

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The mimic octopus (Thaumoctopus mimicus), number 1 on many muck divers’ wish list

The results of the surveys won’t come as a shock for avid muck divers or people in dive tourism, but do seem to surprise from people unfamiliar with muck diving. Here is the top 10:

  1. Mimic octopus / wunderpus
  2. Blue ringed octopus
  3. Rhinopias
  4. Flamboyant cuttlefish
  5. Frogfish
  6. Pygmy seahorses
  7. Other octopus species (e.g. Mototi octopus)
  8. Rare crabs (e.g. Boxer crabs)
  9. Harlequin shrimp
  10. Nudibranchs

While other species such as seahorses or ghostpipefishes are also important to muck divers, a dive location that does not offer the potential to see at least a few of the top 10 species is unlikely to attract many divers.

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Nudibranchs (Tambja sp.) are always popular with photographers

Some differences did occur between diver groups of divers. Older and experienced divers seemed more interested in rare shrimp than other groups. The preferences of starting divers was poorly defined, but their dislikes were most pronounced than experienced divers. Photographers in particular are interested in species like the mimic octopus, potentially because of their interesting behaviour, although that would have to be investigated in a follow-up study.

The final step of our study was to look at how much we know about the animals most important for muck dive tourism. The answer is simple: not much. For most species researchers have not yet investigated if they are threatened, or not enough is known about them to assess their risk of extinction. It does not look like this will chance soon either. The combined amount of research conducted on the top 10 species in the last 20 years is less than 15%  of the numbers of papers published on bottlenose dolphins (1 species) in the same time. Which are not threatened by extinction in case you were wondering. To give you another comparison, from 1997 until now, 2 papers have been published on the flamboyant cuttlefish, compared to more than 3000 on bottlenose dolphins.

Don’t get me wrong, I am not saying we should stop researching dolphins, but perhaps it is time that some of the research effort and conservation money is also invested in the critters that make muck divers tick?

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Harlequin shrimp (Hymenocera elegans), popular with divers AND the aquarium trade

New publication: Parasites on the Great Barrier Reef

This is blog is a story about more than just a new publication, it is also the story of how I became a full time marine biologist. The publication might have come out only last month, but its story began more than 5 years ago on an expedition site in the Philippines…

It is on that site where I met my good friend Eva, who asked me at the end of the expedition if I wanted to join her on the Great Barrier Reef (GBR) for a couple of months of fieldwork. At that point I had no idea that we would be studying cleaner wrasses and parasites, but who would say no to such an offer?

Male adult Gnathiid parasite

A male gnathiid parasite

So November 2012 found Eva and me in a tiny plane, on our way to Lizard Island while¬† enjoying the amazing views over the GBR. The fantastic research station on Lizard Island would be our home for more than three months while we were conducting a series of experiments designed by Dr. Lexa Grutter, one of the world’s experts on cleaner wrasses and fish parasites.

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Lizard Island in the Great Barrier Reef

The experiments we were doing are part of a much larger project that’s been ongoing since the year 2000. The base of the project are 16 small patch reefs, half of which have had their cleaner wrasse removed from the start of the project, and the other half was left alone. To make sure the “removal reefs” stay cleaner wrasse-free, they are regularly checked for new cleaner wrasse, which are removed when found. This amazing setup makes it possible to see how reefs without cleaner wrasse are different from reefs with cleaner wrasse.

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Eva and one of our “Hemis” (Thicklip wrasse / Hemigymnus melapterus)

Our particular experiment was designed to test if the number of gnathiid parasites (basically the mosquitos of the sea) were different when there are no cleaner wrasses on a reef. Cleaner wrasse eat the parasites off fish, but it’s unclear if they eat that many that it has an effect on the total number of parasites on coral reefs. The best way to count parasites is by using living fish as bait, Eva and me used the beautiful thicklip wrasse (Hemigymnus melapterus – aka “Hemis”). Our lovely hemis were put in traps which were placed on the different reefs for 12 hours. The traps are specifically designed containers that let the smell of fish out, and would allow parasites to enter, but not to escape.

We did two main sampling periods, each three weeks long, centered around the full moon. During sampling, our daily routine was to get up well before sunrise, collect the fish that were put out the night before, and deposit a new batch of fish. The main part of the day we would collect the parasites from the traps, and tend to our Hemis and their aquaria. At sunset we would collect the morning traps + fish and deposit a new batch of traps + fish. The days ended with collecting the daytime parasites. I can say in all honesty that I haven’t done such a tiring, but simultaneously exciting fieldwork experiment since.

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The end of a big experiment: time to celebrate!

The work we did provided only half of the data, more data was collected from similar experiments conducted by other colleagues, using different fish species. Afterwards there was a lot of lab work done by yet other collaborators, who counted and identified all the parasites. Only then could the data by analysed and written up. Sometimes experiments are quick and easy, sometimes they take a massive team effort!

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Parasite trap on the reef

So the¬†results are in now, and they are very cool. The main story is that when cleaner wrasse are present on a coral reef, they indeed have an effect on how many parasites infest fishes. But… The effect only happened by day, and only for big fish species such as our thicklip wrasses. For smaller fish species like damsel fish, there was no difference whether or not cleaner wrasse were present on the reef. Also very interesting is that cleaner wrasse only have an effect on the parasites that are active by day.

 

What does this all mean? In short, it seems to indicate that cleaner wrasse not only directly remove parasites from fish, but they do it so efficiently that it keeps the parasite numbers down in the areas where they clean fish. This is in turn good news for all the other fish on the reef, as living in an area with less parasites is much better for your health than living in a place full of parasites. Just think about it, how much would you enjoy living in a mosquito-ridden swamp? This experiments shows that cleaner wrasse are at least partially responsible for removing the mozzies from your swamp!

This paper means more than that to me, it means very fond memories of tiring sampling sessions, crazy-pants parties, beach runs, sunset drinks, meeting some fantastic people,… But more than that, the work involved made me realise how much I enjoy doing research, and it is what made me decide to pursue a PhD in marine science. So being able to write a blog about this paper while I am in the final stages of writing up my PhD thesis very much feels like things have come full circle.

 

New publication: Finding fluorescent critters

Great news! I can finally share the reason why I was playing around with fluorescent torches for the last three years. The main biofluorescence paper I have been working on was published two weeks ago in the journal Conservation biology, happy days!

Previously I have written blog posts about funky biofluorescing fish, publications on frogfish that might be using fluorescence to attract prey, or just some funky fluo pictures to keep you you entertained. This particular story is about why I started working on biofluorescence in the first place and how the results of the research might help to protect little critters.

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Biofluorescent painted frogfish (Antennarius pictus)

As anyone who has ever tried to find small or camouflaged critters during a dive will be able to tell you, the little guys are pretty hard to find! This isn’t just a problem for a dive guide who wants to show pygmy seahorses or small frogfish to his divers, it is also a very real and well-known problem for marine biologists trying to study them. Finding these “cryptic” critters might be a headache for divers, but there is much more at stake when you are trying to collect data about critters that might be endangered with extinction.

If you are trying to figure out if an animal is endangered, the obvious first thing you want to know is “how many of them are out there?”. All good and well when you are studying elephants or giraffes, but slightly more tricky when you’re studying pygmy seahorses or a tiny goby that’s less than 3cm long! Not finding any pygmy seahorses or gobies could just mean that you didn’t look hard enough.

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Biofluorescent moray eel (Gymnothorax zonipectis)

Scientists have three different ways of coping with this issue:

  • First option: Ignoring the problem by not counting small, cryptic animals when doing surveys. After all, if you weren’t looking it’s only normal you didn’t find any.
  • Second option: Adapting standard “visual surveys”. Usually by going slower or looking harder at a smaller area than when looking for big fish. This way you find more cryptic critters, but a lot still depends on how good a researcher is at spotting small fish.
  • Third option: (you might not like this one) Using chemicals that either stun or kill all the fish in a small area, after which all the fish are collected and counted. This method is very efficient and gives a good idea of which fish were living in that area. Unfortunately using methods that kill fish are not ideal, especially when you might be dealing with rare species.
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Two fluorescent seahorses (Hippocampus subelongatus)

This is where biofluorescence could come in to help. If you are confused about what biofluorescence is, definitely check out this post or this website. But briefly, biofluorescence happens when fish first absorb light and then reflect it in a different colour. Importantly, biofluorescence is  not the same as bioluminescence, where animals produce their own light.

So what has biofluorescence to do with finding cryptic fishes? A few years ago, a paper was published that stated that biofluorescence is common in camouflaged fishes. The work looked into evolutionary history, but the main idea triggered a little light bulb. I had previously seen coral researchers use biofluorescence to find baby corals (which are tiny, transparent, and VERY hard to see), so I wondered if the same technique could be used on cryptic fish.

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The same bandtail scorpionfish (Scorpaenopsis neglecta), with and without fluorescence

So I decided to test it as a part of my PhD. I was very lucky to get support from multiple divecentres which helped me to go fluo-diving all across Indonesia and the Philippines. In the last 3 years I did over 200 dives observing, investigating, counting, and cursing fluo-and non-fluorescent fish. The results are published here, but the answer is: Yes, you can use biofluorescence to count cryptic fishes.

The vast majority (87%) of cryptic fishes I tested showed biofluorescence, compared to a small fraction (9%) of the non-cryptic fishes. A cryptic fish is 70.9 times more likely to be biofluorescent than a non-cryptic one! When comparing normal surveys with fluorescence surveys, I found three times as many triplefins (a small cryptic fish species) when using fluo surveys than during comparable normal surveys.

What was also really exciting (to me at least) is that I discovered that pygmy seahorses are fluorescent as well! Using fluorescence I found twice as many Bargibant’s pygmy seahorses than without the fluo torch. As if they weren’t cute enough already, these little guys are fluo pink when you look at them with the right tools!

Fluorescing seahorses are not the only reason why I am excited about this new publication…although it probably plays a bigger role than it should in order to call myself a serious scientist ūüėČ The great thing is that this is an easy and cheap technique that could help researchers study and conserve small fishes more efficiently than before. And in the end, that’s what it’s all about for me, making sure the oceans remain an amazing place full of critters to enjoy looking at…

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Robust ghostpipefish (Solenostomus cyanopterus) are biofluorescent too!