More fieldwork discoveries in corona times: Sangihe

In the previous blog I described how my colleague Alessia and me explored Alor, on a mission to collect environmental DNA and study Indonesia’s remote reefs. I am still stuck at home in corona times, so what follows is the next leg of our trip. After we left Alor, we headed to an island that’s been a tempting dot on Indonesia’s map for a while: Sangihe. This particular trip was supported by a National Geographic grant to investigate Indonesia’s remote reefs.

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The tiny speck on the map that is Sangihe Island

To get to Sangihe, you have to pass through Manado, from there you can either take a long ferry ride or a tiny plane very early in the morning. Flying to the island is a great way to admire the volcanic activity that has formed the islands. Multiple volcanoes surround the airport in Manado and you fly over a few more dotted in the Celebes sea before landing in Sangihe, which has its own large volcano (Gunung Awu).

Sangihe fisherman

Fisherman in Sangihe. Photo credit: Maarten De Brauwer

The island itself is gorgeous, covered in forest with deep blue water around it. Being so remote, the place gets few divers, so dive facilities are nearly non-existing. When we were there (March 2020), the only place to rent equipment was the tourist info centre in Tahuna. Jemmy, who runs the shop is a great guy who went out of his way to help out were possible. Logistics were not quite on point yet since he only started in the scuba business a few weeks before we got there, but fieldwork logistics rarely are on point, so we still got to explore and collect the data we needed.

 

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Sangihe boat views. Photo credit: Maarten De Brauwer

What stuck with me most about the sites, is the incredible visibility, which was 30m at the worst of times and up to 50m at some of the best spots. Otherwise, the health of the reefs was not as good as I hoped it would be. Some sites had extensive dynamite damage, others looked like they had bleached, and the northern sites were strangely devoid of coral, but also lacked the evidence of any typical human impacts. Bare in mind that we were exploring, and neither our fixer Jemmy, nor the boat driver had taken divers or snorkelers to most of the places we sampled. So there was a lot of searching, looking for spots, and the times we got it right, diving was as good as some of the very best Indonesia’s got to offer.

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Not a bad place to sample eDNA. Photo credit: Maarten De Brauwer

One of the cooler experiences during our time in Sangihe was exploring a small freshwater creek that entered the sea at the beach where we were having a surface interval. This small, fast-flowing river wasn’t only absolutely stunning to look at, it was also home to some very exciting fish life. Besides some very cute blue streamgoby (Sicyopterus lagocephalus), it also sheltered a healthy population of freshwater pipefish (Microphis retzii)!!! While I knew they existed, I had never seen them myself, so discovering a creek full of them definitely made my day!

Unfortunately, the next leg of the trip was cancelled due to the spread of COVID19. We were planning to head to an ever more remote island (Pulau Talaud), but the risk of getting stuck there grew a bit too serious. We managed to get a short sampling trip in at the more accessible Bangka island, but eventually had to cut our time short there as well. After only 2 nights on the island, we were told by both the university and friends in the government that the safest course of action would be to leave the country and head back to Europe. Where, at the time of writing, I still am…


A small word of warning for those of you reading this and feel like going for a diving adventure. Sangihe is proper frontier diving with lots of exploring to do. The island has few other sources of income than fishing and coconut farming, so tourism could boost livelihoods in the areas. Just be aware that safety protocols are not as well-established as they are in other, more touristy areas of Indonesia. You should be an experienced scuba diver who can deal with strong currents, basic conditions, and limited to no safety backup from operators.

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Yellowfin tuna for sale at Tahuna market. Photo credit: Maarten De Brauwer

Fish market Tahuna_tuna head

Tuna head was had. Photo credit: Maarten De Brauwer

Fishmarket

A man and his skipjack tuna. Photo credit: Maarten De Brauwer

New research project: diversity in Wallacea

A few weeks ago I wrote about starting an exciting new project at the University of Leeds. At the time I didn’t go into details, but now that I’m a few months in and I am starting to understand what is going, so it’s time to enlighten you as well.

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Coral reef critter research coming up!

For the next two years I’m part of a team that will study marine biodiversity on coral reefs in central Indonesia. The overarching goal of of the project is to improve the management and conservation of coral reefs by discovering how impacts such as pollution or overfishing change the way coral reefs function. After all, the best way to start solving a problem is by properly understanding it.

Obviously, there’s a lot more to it than the lofty big goal as the title of the project indicates: “Gradients of marine biodiversity and linkages with eDNA across the Wallacea Region”. There are two components to the project: traditional visual surveys and environmental DNA (“eDNA”) surveys. We will use both methods to create ecological networks and see how they differ when they are threatened by different impacts.

At this point you might be asking a few (logical) questions:

  • Where is the Wallacea region and why do you go there?
  • What is eDNA?
  • What is an ecological network?
  • Why should I care? I came to this site to read about critters!

The Wallacea region is the central part of Indonesia, from Lombok eastward almost all the way to Papua, and up all the way to Halmahera (check out the map below). It was named after Alfred Russel Wallace, the scientist who, together with Darwin, developed the theory of evolution. The region represents an interesting boundary area where fauna and flora from the Asian and Australian continents meet. So it is home to some amazing wildlife, but also to a large human population that depends on natural resources to survive. The marine diversity in the region has not been studied very well (except for a few local exceptions), so finding out how healthy the marine ecosystems are is quite important.

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The Wallacea Region

Environmental DNA (eDNA for short), is a relatively new method to detect species. I have written about it extensively here if you want a long explanation and background. The method detects tiny fragments of DNA in the water column that are shed through poop, mucus, etc. By filtering and analysing a scoop of water, we can tell what animals (and plants, microbes, etc) live in the water nearby. It’s pretty powerful and very exciting, but still needs a lot of additional testing to know just how precise it is compared to other survey methods.

I will then build ecological network models with all the data we collect. The easiest way to imagine what those are, is to see them as a different kind of food web. Where food webs focus on who eats who, we are more interested in who lives close to who, and who interacts with who. In the ideal situation I will include all the information on fish, corals, algae, invertebrates (crabs, sea stars, etc.) in one big model which will show how they rely on each other. More importantly, it will also show what happens with the networks if sites are overfished or polluted and how that differs from untouched sites.

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Example of an interaction network on land, figure by Bohal et al. 2013. Source here.

So yes, my job for the next few years is less critter-focused than before, but it doesn’t mean I will be ignoring them! Besides the obvious fact that there’s a lot of cool critters to be found on the coral reefs I’ll be visiting, I am still involved in a few very cool projects on the side. It’s too early to go into details, but more seahorse and seadragon work is coming up, and even some exciting pygmy seahorse news as well! I’ll regularly be posting updates on the Wallacea project, as well as more critter features, so stay tuned 🙂

New publication: For clownfish sharing means caring

Best of Bali_Clownfish and Periclemens shrimp_MDBWhile I am currently immersed in an amazing project investigating muck critters, I have done research on more conventional fish in the past. One of those conventional fish, is the ever popular clownfish (aka “Nemo”). Clownfish might not be quite as amazing as Frogfish or Rhinopias, but they are pretty interesting and funky fish nonetheless.

Last week the research I did 2 years ago in Wakatobi got published. When I write the research “I” did, what I really mean is the research my good friend Emma Camp and me did with the help of a great bunch of people of Operation Wallacea. Besides these great people, there were some terribly clever people from the University of Essex and Curtin University who helped to make this a really neat paper. If you are interested, you can find the paper here,  but I’ll assume you haven’t got much time so here is the short version of what we found out.

As you probably know, clownfish live in anemones. What you might not realise is that there are 28 species of clownfish and only 10 species of anemones that can be used as a “host” (aka house). Usually you’ll only find one species of clownfish per host anemone. In places where lots of different species of clownfish live, you would expect a fierce competition for their hosts. But what we found in the Coral Triangle, is that clownfish instead share their hosts. The higher the diversity, the more often clownfish share their host anemones. What this means is that house sharing helps to create and sustain the high diversity we find in the Coral Triangle.

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Amphiprion melanopus (large fish) and A. perideraion (small fish) sharing an anemone

What is more, the species that shared their anemones were less aggressive towards each other than in anemones with only one species. This is probably because different species don’t have to compete over mates or (in some cases) over food, a win-win for all fish involved. After all, anyone who ever shared a house knows it’s easier to get along when  you don’t steal each other’s food or partner.

If you want to read more about this research, you can have a look at the media release or this summary. Or you can ask me whatever you want about it in comments below, certainly in case you can’t access the original paper. I’m planning to add a publications section to this blog in the near future, so stay tuned.

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Amphiprion melanopus (large fish) and A. perideraion (small fish) sharing an anemone

 

 

Fieldwork 2.0

It’s that time again, after a few months of hiding behind my computer I’m starting the second big fieldwork season to collect data! I just arrived in Bali to sort out the last preparations for what will hopefully be a productive three and a half months of data collecting. I’m pretty excited about this trip, as I will be visiting some amazing places again where I’ll be working with great people!

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Home for the next 2 weeks

It all kicks off early tomorrow morning, when I’m leaving on a liveaboard trip to Komodo for two weeks. Safari Bali has once again kindly offered me a place on the Sea Safari VII, so I should be very comfortable while I’m trying to find frogfishesghostpipefishes and maybe the occasional manta ray or dragon. Once I get back from Komodo, I’ll be spending a fair bit of time in Bali again before heading to Lembeh Strait. The main thing I’m trying to figure out in Indonesia this year, is which human factors have the biggest impact on muck critters.

Like last year, I will again be doing presentations about marine biology and having long conversations with divers while I’m on the boat and staying at dive resorts. Some people might see this as a time consuming interruption of valuable research-time, but I really enjoy this aspect of my fieldwork. I feel it’s important as a researcher to share what you are doing with people who aren’t in academia themselves. What would the point be of all the work we do, if only a very select group of other researchers get to know about it?

ADEX

Which is why I am looking forward to the next stop after Lembeh: ADEX in Singapore. ADEX is the largest dive expo in Asia, with thousand of divers coming over to try to decide where to go for their next trip or what the newest trends are in the scuba diving world. I am very excited to have been invited to give a few talks about my research. In line with the theme of ADEX this year (Seahorses), I’ll be talking about pygmy seahorses, which I haven’t really done yet on this blog…

For the final leg of this trip I am heading back to Dauin in Philippines. Those of you who have been following the blog, will understand that I am rather happy that my good friend Luke (aka the Science Hobbit) is joining me again! Together we will be trying to figure out the best methods to study newly settled (=baby) critters. If you want to know how we’re planning to achieve that and whether or not we’ll succeed, keep an eye on the blog 😉

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Baby frogfish (A. pictus), finger for scale