On the origin of muck diving

The last 3 years of my life have been dedicated to intensely studying critters and socio-economics related to “muck diving”. While this is a relatively common term in the scuba diving world, the vast majority of people haven’t got a clue what muck diving is. I can’t count the number of times people at conferences, meetings, drinks, etc. have gone: “You study what diving???”. Marine scientists seem to prefer hearing “Cryptobenthic fish assemblages on tropical sublittoral soft sediment habitats” than “Critters in the muck”. Each to its own I guess?

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Classic muck diving scene (Photo: Dragos Dumitrescu)

It’s not just scientists who are confused, a lot of divers have questions about muck, or at the very least are curious about how it started and where the name came from, so I decided to dig a bit deeper and find out some interesting facts about the origins of muck diving. If you have never heard of muck diving or just aren’t sure what it is, here is how I defined it in my last paper:

“Scuba diving in soft sediment habitats with limited landscape features, with
the explicit goal to observe or photograph rare, unusual, or cryptic species that are seldom seen on coral reefs.”

Or easier: Diving on sand/mud/rubble to find cool animals you don’t see on normal divesites. The word “muck” means either “Dirt, rubbish, or waste matter” or even worse “Farmyard manure, widely used as fertilizer”. In British English it is also used for “Something regarded as distasteful, unpleasant, or of poor quality”. I would guess that it’s the combination of the first and last meanings that inspired the people who started this type of diving.

Muck diving in its current shape has its origins in Milne Bay, Papua New Guinea. On a site called Dinah’s beach,  where Bob Halstead decided to try to do a dive on the site where their boat (the MV Telita) was anchored. The divers were skeptical at first as the site was mostly sand and did not look very appealing, but after discovering tonnes of creatures they had never seen before they were sold and muck diving was born. From its origins in Papua New Guinea, muck diving caught on and became popular across the world, but no place is as well known for muck diving as Lembeh Strait in Indonesia.

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Milne Bay, Papua New Guinea, where it all started

It is clear why Lembeh is famous with muck divers, as it really is a great place to dive and find some of the world’s most amazing critters. But how did muck diving in Lembeh kick off? What many people don’t know, is that Lembeh’s origin-story as the world’s most famous muck dive destination is pretty grim. The first resort in Lembeh (Kungkungan Bay Resort) was built in 1994, but the owners did not build their resort with critters in mind….

Back in those days, Lembeh was one of the best sites in the region to watch the big stuff. The plankton-rich waters of Lembeh Strait attracted scores of manta rays, dolphins, sharks,… Until 1996, when mankind showed just how destructive it could be. In March of that year, foreign fishermen came in and (illegally) installed the “Curtains of death”. These were huge nets, placed across the migratory routes of the large fish near Lembeh Strait. The nets were deadly efficient, during the 11 months they were used they caught:

  • 1424 manta rays
  • 577 pilot whales
  • 18 whales
  • 257 dolphins
  • 326 sharks (including whale sharks)
  • 84 turtles
  • many other animals including turtles and marlins

The original article about the curtains of death can’t be found online, but if you are interested, send me an email and I can send a copy. If you want to know more about destructive fishing in Indonesia, this is an interesting source start with.

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Peaceful Lembeh Strait has a turbulent history

The numbers are staggering, and for the few tourism operators in the area it must have been quite a shock. Until they discovered that Lembeh had much more to offer than just the big stuff. While there are no records of it, the story goes that muck diving in the area only properly got started when people started looking down at the sand instead of up at the manta rays. It makes me wonder what the area would have looked liked otherwise, and if muck diving would exist in the way it does now…

As it is now, muck diving is big, it attracts divers from across the globe and new critter hot spots keep on being discovered far beyond from where it all started. It’s exciting to think about how much more we will discover in the future! For me, one of the changes I would like to see, is the actual term “muck diving”. The name coined by Bob Halstead stuck, but I think most people in the diving (and academic) world agree that it isn’t really the most inviting name. I’d like to hear your suggestions (below in comments) on more suitable names for this type of diving and the divers doing it. If I get enough suggestions, I’ll organise a poll later to see what is preferred by divers around the world!

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It’s all about finding the small stuff – baby Painted frogfish (Antennarius pictus)

PS: Originally I wanted the full title of this blog to be “On the origin of muck diving by Means of Photographer Selection, or the Preservation of Favoured divesites in the search for Critters”. But the long title might have put off those readers who didn’t immediately get the very nerdy biology pun.

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Writing, Seahorse conferences, and Australian coral reef talks

I’ve had a busy few weeks, so it has been a bit quiet on the blog. To make up for it, here is what I have been doing lately instead of writing blogs…

This might surprise you, but doing a PhD in marine biology is about more than just going to tropical beaches, diving and looking at cool ocean critters. By now I have collected all the data I need to write up my PhD, so what is left is mostly sitting at my desk, analysing data and writing that data into something that will eventually become a  doctoral thesis. At the moment I’ve written about 40 thousand words (~90 pages), which might seem like a lot, but in reality I’ve still got a lot of work to do (just have a look at the figure below by Beck on R is my friend).

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Median length of a PhD thesis per field.  Link to original source.

Besides writing, there’s a lot of statistical analysis to do. I never expected to write this, but doing stats is actually quite fun (and excruciatingly painful at the same time). There is just something about having collected data, then getting to test your hypotheses and turning all of that into graphs and results. To me, the feeling of turning your ideas into new, real information is probably one of the most gratifying aspects of doing research. That, and sharing your fresh results with people and listening to other people share their new work.

That is where scientific conferences come into play. Over the last years I have attended a few big and not so big conferences, which were always good fun. Last May and July I presented different aspects of my research at two smaller, but very interesting conferences: SyngBio 2017 and the ACRS 2017 conference.

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Participants of SyngBio 2017 (Tampa, Florida)

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Tagging workshop at SyngBio 2017

Syngbio stands for Syngnathid Biology, but it really should be called seahorse camp. Syngbio is a global conference solely focused on Syngnathid fishes (=seahorses, pipefishes and their relatives). The conference was held at the University of Tampa in Florida (USA). For the duration of the conference we had accommodation in a dorm on campus, which contributed to the “summer camp”-feel and additionally made it a lot easier to socialize (read: “drink alcoholic beverages”) with other researchers at the end of the day. I must say that this conference was the most fun conference I’ve done so far, even if I leave out the social events. Hanging out with a group of people who are all passionate about the species you study is great, especially since I usually work with people who study very different species than I do. There was so much to learn from experts on all kind of topics ranging from conservation, to physiology, husbandry, ecology, evolution, etc. I was also lucky enough to attend a meeting of the IUCN Syngnathid Specialist Group, which are the people who decide on global conservation priorities for these animals. During the conference I presented my own research on the impacts of flash photography on seahorses. The writing on that chapter isn’t entirely finished yet, but I will make sure to share results here as soon as they are published.

The other conference I attended was organised by the Australian Coral Reef Society (ACRS), who kindly sponsored my flights to Townsville (Australia) to attend the conference. Townsville  is the home city of James Cook University (JCU), one of the world’s leading marine biology universities. Over the years I have met a lot of JCU researchers in the field and on other conferences, so it was great to finally visit the place and catch up with everyone. The conference had a strong focus on the recent coral bleaching events on the Great Barrier Reef and how it eventually effects far more than just the corals. While certain (uniformed) people still claim otherwise, climate change was one of the main reason this happened, and will probably happen even more in the future. This isn’t the blog post to go into depressing details, but seeing the destructive effects for yourself and talking to the scientists who do the research really drives homes the message of how important it is to take action to slow down climate change.

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A Tambja nudibranch (Tambja sp.), winner of “public’s choice”-award at ACRS 2017

I presented some of my biofluorescence research at the ACRS conference and was very happy to win an “Outstanding presentation award” for my talk! The work I presented is in review at the moment and will hopefully be published within the next 3 months. During the conference I also submitted a few of my photos for a conference photo competition. I am quite proud that one of the photos won the “Public’s choice” award! 🙂

So what are the plans in the near future? I will definitely try to write blogs more regularly, although I have a pretty busy schedule. I am tutoring a few classes (Functional Biology) to 1st year students, and I will be doing a lot more writing and analysing.  I might get some short relief from the cold Perth winter to do another trip to Coral Bay with the 3rd year students as well, which would be good fun. Finally, I’ve got three papers which are in review, so hopefully I will be able to share more news about new publications soon!

 

 

 

What is a species?

As promised in a previous blogpost, it is time to get into another hotly debated topic in biology that most non-biologists wouldn’t even think was an issue at all. This is a big one, as it underpins pretty much all biology: “What is a species?”. I would argue that this question needs two important additional questions: “Why does it matter?” and “To whom does it matter?”. Since I am only human and like postponing difficult tasks at hand, let’s start with the follow-up questions.

speciesTo whom does it matter that we are capable of telling one species from another? Besides looking like a smart cookie when telling your fellow divers/birdwatchers/plant enthusiasts which species you’ve just seen, it doesn’t matter very much to be honest. We are no longer hunter-gatherers, so being able to tell which species you can eat, and which ones will will eat/kill you, doesn’t matter that much anymore. In other words, the discussion in the rest of this blog is mostly an issue for taxonomists, but it gives an interesting insight in how simple concepts can be quite complicated when you look closer.

Why does it matter then? For two reasons:

  1. People in general and scientists in particular like putting labels on objects around them, it helps us structure and understand the world we see.
  2. Being able to tell two species apart that look very similar can have big consequences for conservation action: Two birds/fish/plant might look similar, but they could be different species, one of which reasonably common, but the other one rare and on the brink of going extinct. If we don’t realise they are different, we might lose that species.

A logical follow-up question (in my mind) would be: “what does it matter if one species that looks a lot like the next goes extinct?”. This is a valid question, but would require a long (and interesting) scientific and philosophical discussion.

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Struggling to define what a species is? Don’t worry, so did Charles Darwin (photo source: www.brainpickings.org)

Back to the species concept, which seems obvious, but really is not. The question has been asked for centuries by many renowned scientists. Two of which were none other than Charles Darwin and Alfred Russel Wallace. It could even be claimed that this question is what eventually led to the theory of evolution, which essentially tries to explain how different species come into existence. It is obvious that you need to know what a species is before you can answer that question. Sometimes it is easy: the majority of people can tell the difference between a cat and a dog, but it becomes a lot more difficult when species look very similar. Try asking a marine biologist what the difference is between a Slingjaw wrasse (Epibulus insidiator) and a Latent slingjaw wrasse (Epibulus brevis), or between a Thin Ghostpipefish (Solenostomus leptosoma) and a Robust Ghostpipefish (Solenostomus cyanopterus). Go on, give it a go, it’ll be fun to see them struggle! (Smart-ass tip: a spot on the dorsal fin & smaller adult size / No difference, they are most likely the same species).

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They might look different, but are the same species. Photo source: www.dogguide.net

The problem is how do you define a species? At what point is an individual that looks different than “the norm” a different species, rather than just natural variation? Dogs can look as different as Danish dogs and (rats) Chihuahuas but are all the same species. Compared to those two, lions and tigers look much more alike, yet they are very different species. The classic definition of a species (if they cannot have fertile offspring they are different species) works in most cases. Lion + Tiger = Liger, but ligers are infertile. I don’t know what Danish dog + Chihuahua would look like and I wouldn’t get ethics approval from my university to test it, but presumably the result would be a fertile dog.

So far the normal situation, but what happens when different species mate and have fertile offspring (hybrids)? This is surprisingly common in the ocean. Hybridising fish are not that rare if you know what to look for. I have personally seen it in Clownfish and Surgeonfish and almost certainly in Frogfish and Ghostpipefish. But is has also been recorded in groupers, manta rays, butterflyfish, angelfish and wrasses.

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Hybridising surgeonfish: r: Acanthurus lineatus s: Acanthurus sohal t: A. lineatus x A. Sohal hybrid (Source)

In this case, can we say the parents are different species because they look different, behave differently, and typically live in different regions? Or are they a single, highly variable species, the way dogs are? Traditional taxonomy focused on what species looked like, would say they are different species, but not everyone agrees with this. A recent example from the pygmy seahorse world: Hippocampus severnsi and Hippocampus pontohi were described as two different species. However, new (yet unpublished) research shows that they are genetically identical, so the name H. severnsi was removed and they are now all called H. pontohi. I’d imagine much to the annoyance of Mike Severns, who no longer has a cool animal with his name on it.

Is genetics the solution to the problem? Depends on who you ask. Geneticists tend to say yes, old-school taxonomists tend to be a bit less convinced. Each side has very valid arguments, one of which is how genetically different do individuals have to be before they are considered different species (sound familiar?). Different cut-offs have been proposed, but as far as I know, there is no real consensus (please correct me if I am wrong geneticist-readers). Another serious issue is how to classify small life forms like microbes, this article has a great summary on that if you are interested.

If you think this is getting too complicated, it might be best not to become an evolutionary biologist or taxonomist, because things actually get a lot more complicated than what I described. Suffice to say, for biologists the term “species” is still not a clearly defined concept. But luckily for non-specialists, the essence of the debate is about such fine details that it really shouldn’t be keep you up at night.

What’s in a (species) name?

A recent publication about the family tree of manta and mobula rays got quite a lot of attention on my social media feeds, inspiring me to explore the topic a bit further. I’ll try to keep this blog as jargon-free as possible, but I apologise in advance if I occasionally veer off into technical terminology.

Manta and me

Manta-selfie in younger days

Before I get going in earnest, a quick introduction to scientific names (or “binomial nomenclature“). Scientific names consists of two parts, the first part is the genus of the species (a bit like your surname), the second part the actual species name (like your first name). A few examples: Antennarius pictus, Homo sapiens, Wunderpus photogenicus. Names are usually in Latin or Greek, or anything that vaguely sounds like either one of those. Unlike common names, the scientific names for species are the same wherever you go in the world, which is helpful when talking to scientists who speak a different language than you do.

So what is the manta vs. mobula article all about? Manta rays are large, charismatic fish that grow up to 7m wide who look and feel a bit like stealth bombers when they glide over your head during a dive. Until recently, two species of manta rays were recognised: Oceanic manta rays (Manta birostris) and reef manta rays (Manta alfredi). Mobula rays look very similar to manta rays, but are smaller and differ from mantas in a few other ways. The newly published paper did genetic research to see just how closely mantas and mobulas are related, and they turn out to be a lot closer related than we previously thought. To put it into human perspective, as a species manta rays were thought to be something like a cousin to mobulas, but they turn out to be more like a brother/sister. In biology-slang: manta rays are now seen as belonging to the same genus as mobula rays. Which in turns means that their scientific name changes from Manta to Mobula, so Mobula birostris and Mobula alfredi. A bit like an adopted child getting a new last name.

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Reef manta rays (Mobula alfredi) – Photo by Luke Gordon

What the article does NOT claim, is that manta rays are now suddenly a different species. It just means they are classified differently by taxonomists (and that they might get more invitations to Mobula social events). The common names will remain the same, manta ray species do not suddenly disappear or behave differently. It will take a while before ID guides will pick up on the name change and a lot longer (if ever) before the majority of ocean enthusiasts will notice.

A good point made by a friend, is that a different scientific name means certain official documents concerning the trade in protected species might have to be adjusted. Luckily the statute of manta rays as a species is not questioned, so existing conservation laws should not need to be changed.

But how does this happen? Why do scientists decide that a species has a different family tree than we’ve always thought? This is actually not an uncommon event, in the last years many species (including nudibranchs and frogfishes) received different names and classifications. One reason is that science is constantly evolving and as we learn more, we update our knowledge and correct mistakes from the past (or make new mistakes which might in turn be corrected later). In the manta/mobula-case: by using modern methods we found out that the family-relations were different than we assumed from only looking at the anatomy of these animals.

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Manta ray (Mobula alfredi) making its stealth bomber-like approach

Another (more surprising) reason, is that we still don’t have a good definition of what a species is. Human nature impels us to order the world around us into categories with different names, initially very broad (animal / plant / rock), then more detailed (fish / mammal / bird), more detailed still (ray / shark / frogfish), until you reach the scientific naming system (Mobula birostris / Mobula alfredi / Mobula mobular). But sometimes it is difficult to decide where one species stops and another one ends.

I know that at school you get taught that two species are different when they can’t produce fertile offspring (Horse + Donkey = Mule, but mules are infertile, so horses and donkeys are different species). To a large extent this definition works, but it breaks down when you start looking closer, especially when you look in the ocean. The question on how to define a species is a surprisingly hot topic in biology! I will explore the species-definition problem in a different blog later (promise!), but it would make this one a bit too long.

In the meantime, you can call manta rays Mantas, Devil rays, Big-ass mobulas, or anything else that floats your boat. As long as you have a great time watching them and try to protect the environment they live in I’m happy!

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Does it really matter what these beautiful animals are called? Photo by Luke Gordon