Elizabeth Passea

‘Reef Safe’ Sun Protection: an update

We have previously written about the damaging effects of sunscreen on coral reefs and have banned the use of commercial non ‘reef safe’ sunscreens at Reef Doctor. In this new blog, Reef Doctor volunteer Elizabeth Pasea updates us on the issue and recommends the best approach for protecting your skin from the harmful effects of UV radiation with minimal impact to coral reefs:

“Growing up under a hole in the ozone layer in New Zealand, I was aware of how important sunscreen is to protect against skin cancer. I have more recently learned that the ingredients in most commercial sunscreens are damaging to coral. Awareness is spreading; Hawaii has recently banned the ingredients octinoxate and oxybenzone due to their negative impact on coral ecosystems.

Studies have shown that even ingredients advertised as ‘reef safe’ can still increase oxidation and acidity levels in water and contribute to coral stress, where they may expel the algae which reside in them and give the coral it’s colour; the process known as coral bleaching. Non-organic sunscreen ingredients, zinc oxide or titanium dioxide, are less toxic than petroleum-based ingredients; however their nano particles may still damage coral.

Elizabeth Passea

80% of the ReefDoctor volunteers currently on camp have titanium dioxide based sunscreen, and 20% zinc oxide. Most of us found that we had to search hard for these products – they were not the most readily available products.

One of the things to notice when arriving in this part of Madagascar is that some of the women wear mud on their faces during the day for sun protection, as demonstrated in the photo below by Reef Doctor Support staff member Hortence. As it happens, titanium dioxide is just about to start being mined in Ranobe, not far from the Reef Doctor camp, science is catching up with local Vezo custom!

local women with facepaint


When diving at Reef Doctor, whether gathering data on the health of the reef or transplanting coral, we try to minimise our application of ‘reef-safe’ sunscreen to dry skin; when applied to wet skin it is liable to rinse off straight away. We also prefer hats and clothes to protect our skin when on the boat and during surface intervals.

It’s not only swimmers and divers who introduce sunscreen and other chemicals to the coral environment: chemicals used on land and washed off into many municipal waste systems also end up in the ocean. A recent study (Corinaldesi et al, 2018) showed that patented titanium based ingredients ‘Optisol’ And ‘Eusolex T2000’ have significantly lower levels of toxicity to coral than zinc oxide. Hopefully, we will see more products with these ingredients available to buy soon.

In the meantime, please read the ingredients! The conservative application of products containing non-nano zinc oxide and titanium oxide applied to dry skin remains the best option to help ensure coral ecosystems survive beyond 2050.”

Blog by Elizabeth Pasea

Photo credits: Elizabeth Pasea & Margot Chapon 

Night Diving in the Bay of Ranobe

In this volunteer blog, Research Assistant Abby Rogerson describes her memorable experience of night diving in the Bay of Ranobe, in what marked her final dive with us.

“I’m always weary of building up lasts. I need no culminating spectacle to seal an experience, and I find that reflections of my past are more often marked by seemingly trivial occurrences that elucidate a time’s importance. Perhaps this attitude is subconsciously built on a foundation of self-preservation—an indifference towards great endings ensures disappointment will not ensue.

My final dive at Reef Doctor was on a calm Friday night at Rose Garden Marine Protected Area. Rather than my interest waning as I became more acquainted with this reef—its resident species, their behaviours and habitats, the geography of the reef perimeter—I’ve become more attached. Familiarity is a settling feeling as a person uprooted from the subtle details that make one feel at home. Despite my reservations about lasts, the prospect of seeing this place in a different light is exciting, akin to visiting a beloved spot with a new companion—the draw remains unchanged, but details are amplified and refracted through a new perspective.

As we make our way offshore, I look back on the once homogenous coastline, which is now distinguished by time spent and knowledge gained. The dottings of dull green-grey trees are now Euphorbia; the faded red bungalows tucked in the dunes are remnants of the dilapidated Mangily Hotel; the dense stand of pines mark entry into Ifaty. Walks along this beach are differentiated by conversations on the phone with missed loved ones, by slow afternoons spent inspecting tide pools, by disjointed French conversations had with children met on my way.

We tie up to a buoy as the sun dips below the horizon. Flicking on our flashlights, we descend down the algae-laden anchor line. The artificial light illuminates particulates drifting in the water column, and I avert my eyes from the cloudy beams. The ensuing clarity is stark; I’m struck that a medium that exerts such resistance is as invisible as air.

Dusk seamlessly merges into dark. Fifteen feet above, I see the moon’s image stretched across the meeting of mediums and elongated into a rippling spectrum of color. With the moon’s light above and the presence of five others around me, I think about a conversation with my mom in which she said night diving must be unnerving. Although I understand the sentiment, the idea of being frightened in this moment seems irrational. To get a sense of this unnerved feeling, I let the others pass by and turn to see the darkness. My mind drifts to the possibility of being solitary in this blackness, and a pang in my stomach urges me to abandon this curiosity.

By night, short-spined urchins roam freely. Untethered from their daytime congregations, they shuffle singly across the substrate and continue their ramblings up the walls of massive coral bommies. Tiny red fish shimmy amongst their spines and reaching tentacles. Constantly I realise how little I know about the inhabitants of this ecosystem, and I wonder if these hitchhikers are parasites or partners in a welcome symbiosis. Three-spot dascyllus have also shed any semblance of shyness. By day, they nip our fingers to defend the eggs they’ve laid upon the coral nursery’s rebar as we scrape algae off its frame. Now, these small, drab grey fish do not dart away like other species as we pass by; rather, they flare their dorsal spines to the alert. Their prevalence and apathetic disposition begs me to label them the squirrels of the reef.

A circling beam ahead catches my attention. My eyes scan the matrix of tan and brown textures and catch the domed form of a cuttlefish—the first I’ve ever seen. Although they are capable of hypnotizing color displays, this one relies on a mottled appearance to keep it disguised among the rubble. A waving flap skirts its squid-like body, which allows it to hover slightly above the seafloor. I reluctantly move on, now distrustful that the broken shards of algae-encrusted coral are as they seem. My suspicion is warranted. An octopus’s bulbous head gives away its camouflage; it is not angular enough to blend into the surrounding mess of coral fragments. As we crowd around, it slithers its tentacles more tightly underneath its body. Its obvious tenseness makes me certain it will flee once free from our attention. Just as my fins pass out of its radius, it launches itself away with a swift extension of its tentacles into the safety of darkness.

Gradually, a faint crackling noise becomes loud enough to catch my attention. Typically, my breath is the only noticeable sound while diving, and it tends to fade from consciousness just as the feeling of breath does. Upon becoming conscious of sound again, I fixate on the mechanical sound of air travelling through my regulator and the purge of bubbles as I exhale. I wonder about the source of the crackling and if the others notice it as well. Although we dive together, each of us has isolated experiences defined by thoughts that cannot be shared, questions that remain unasked, and curiosities that disappear before being pointed out. Our spheres of awareness are separate and overlapping in unknown ways.

This inability to express amazement and confusion is readily relieved upon surfacing. Our hanging flashlights illuminate the water a pool blue as we bob on the surface, breaking the night’s silence with our exclamations and questions. Hypotheses for the source of the crackling are pitched, and descriptions of unknown species discussed. To me, it seems my indifference towards a memorable last dive was met with a barrage of novelty, as if to disprove that this ocean and its many ecosystems could ever cease to be novel.”

Photo credits: Abby Rogerson & Neil Davison 


Diving Beyond the Barrier

In our latest volunteer experience blog, research assistant Abby Rogerson beautifully describes diving the amazing exterior reefs of the Bay of Ranobe with fantastic photos from our Head Dive Officer Neil Davsion.

“Approaching winter in Madagascar is marked by subtle changes: the sand feels cooler on my feet in the morning; the dawn light shining through the cracks in my hut is fainter. On this April day, the western horizon is deep lavender, fading to a rich pink and pale blue overhead. I lean against the compound fence sipping coffee, watching the stream of pirogues paddle across the glassy, pink-reflected water.

As we motor out to the dive site, I’m afraid we’re interrupting the bay’s silence. Fay’s motor whines as we get entangled in a scatter of Sargassum algae. We look back apprehensively as Manjo lifts the outboard to untangle the mass. Fay, the larger of our two boats, has been out of commission for the past four months. Now that her engine is running again, we’re keen to keep it so, as she’s our only way to reach the exterior of the bay. Once freed, we speed across a mosaic of greens and blues as the waterscape below changes. On a clear morning like today, the seagrass fields can be seen swaying lazily beneath the surface, glowing through turquoise water. Up ahead, glints of silver flicker above the water. “Vary lava,” Manjo says. Small, elongate silverfish commonly seined in Vezo villages along the coast.

Waves build as we near the pass, where a break in the barrier reef allows water to flow in and out as the tide fluctuates. Feeling the hull crash against the waves is a welcome change from the calm of the bay. Manjo grows more conservative though, slowing at the wave’s crest just as I anticipate the next smack. Somehow, he navigates us in a featureless expanse of blue directly to our drop point. Now in the exterior, the chop has transformed into a steady swell. The breakers resonate a deep hum as we kit up.

Six tanks hang off the sides of the boat as we signal our ready to Manjo. In typical fashion, he counts down from three and we flip off the boat. Communication is non-verbal now: a fist on the head means we’re okay, and a thumbs-down begins our descent. I let the weight of my tank drag me down back first. Manjo hangs over the bow railing waving, and the outline of Fay’s hull grows distorted as I drop deeper.

RD boat



At 50 feet, the light is hazy and tinged green. Water constantly flows and surges through this area nearby the pass, resulting in a complex geography of tunnels and caverns. What may initially appear as a rocky expanse is actually a plateau carved by a system of canyons.

None of us are familiar with this site, so we haphazardly drop into a sandy gulch enclosed with rocky walls. Familiar fish seek shelter in the overhangs—big-eyed fish that prefer to stay in the shadows during the day. As we fin deeper into the gully, it grows deeper and narrower. Anthias are plentiful here, although they look like they belong in shallow, light-drenched coral reefs, with their tropical coloration and streaming lunate tails. Overhead, the gully converges into a tunnel, and the Anthias swim oriented to the ceiling. Gravity is less relevant here.

We rise out of the canyon. Already, the sun’s shifting rays have brightened the water. Floating over the stunted branching and encrusting corals, I am reminded of alpine vegetation. Strong winds, shrubby plants. Persistent currents and deep water, scrubby coral. Blanketing the substrate is a vast diversity of life—undulating soft corals, colonies of delicate speckled sea squirts, fleshy turf algae, rust-coloured sponges, fan-like stinging hydroids, translucent sea pens, and organisms I cannot yet recognise.”




While obsessing over the micro, I am distracted from the macro. A hand waves in front of my mask and points. Behind me, a magnificent shoal of rudderfish circles from the seafloor upwards. Their scales flash silver as the sun momentarily reflects off them. As they fade from our view, we rise.

Written by Abby Rogerson
Photos by Neil Davison

Walking On The Moon Underwater

Abby is one of our latest research assistant recruits from the USA. With a bachelor in environmental science, she decided to join Reef Doctor to get hands-on experience and to help her decide if she wants to pursue a master’s degree focused on the social or the scientific side of conservation. In her first instalment, she describes her journey underwater building our newest artificial reef…

“Last Tuesday, five Reef Doctor volunteers/staff and I back-rolled off the dive boat, Ray, and descended about 20 feet to the site of our next artificial reef. At that moment, it was a sandy patch of seafloor littered with limestone chunks, enormous barrel sponges, and sea urchins clustered here and there. Our objective was simple—construct rock bommies in order to create habitat for reef animals—but the preparations leading up to this point have been extensive. Think: planning with community leaders, diving to scout a suitable site, hauling 100 zebu-carts of rock to the beach, blessings to wish the project success, and finally, paddling all that limestone a ways offshore to the buoys demarking the site.

Once we all were positioned underwater with our fins off and booted feet firmly planted on the seafloor, Roberto, the Head Science Officer, signaled to us where to build the first bommie. While the others set off to retrieve the concrete piping we planned to incorporate into the bommie as habitat for large fish, I began collecting limestone. Of course, lifting any amount of weight is easier underwater, but it was almost comical to be able to lift and haul armloads of rock with ease. Soon enough, we had all assumed our roles as collectors or builders and were making progress quickly. With six people stomping about and dropping rocks, the most obvious difficulty to overcome was limited visibility—so limited that at times I could hardly see where my foot was stepping. Although this was a bit unnerving given the urchins in the area, we all managed to keep our feet spine-free. Forty-five minutes into the dive, the first bommie was nearly complete and I had breathed enough air to need to ascend.

After a quick lunch and surface interval (nap) on the boat, we swapped tanks and dropped down again. Hovering above our first finished bommie, we could already see sandperches weaving within its crevices and resting upon the limestone surfaces. We finned a few meters away, and Roberto gave us the ‘okay’ to start constructing there. During the previous dive, I had been mainly focused on keeping my balance and checking my air, as it was my first dive beyond the realm of recreational diving. However, on the second, I came to realize why the others had compared this type of diving with moonwalking. With eight kilogrammes on my weight belt, I was heavy enough to avoid floating away, but light enough to leapfrog and launch myself a couple meters. Then once I was weighted down even more with rocks, it was easiest to bound back to the site on the seafloor. With that strategy, four of us were collecting while the other two were carefully selecting and placing rocks. In order to create desirable habitats, it’s important to position the rocks in a way that creates gaps and tunnels, so that small fish and invertebrates can hide within these shelters. On the contrary, it’s even more important to build the structure sturdy enough to ensure it doesn’t topple when confronted with powerful waves.

Again, I was the first who needed to ascend, so my dive partner, Katharina, and I headed up. A few minutes later, the others finished the second bommie and joined us. With the wind blowing towards us, we made a slow journey back to ReefDoctor. In the coming weeks, we will work to complete the next eight bommies. The finished artificial reef will be named Vato Mahavelo II, after our very first artificial reef located next to the MPA Rose Garden.”

Written by RD volunteer Abby Rogerson

Photo credit: Karin Moehler

A Healthy Life From a Healthy Sea

At the beginning of the year, three German students came to Reef Doctor to start an aquaculture farming pilot project in the Bay of Ranobe. In this blog, Jasmin, Wiebke and Anna tell you more about their project, objectives and hopes.

“Our project comes from the student initiative Enactus Aachen e.V., Germany, a registered association composed of students of the RWTH and FH Aachen since 2015. We have made it our mission to improve the living standard, the quality of life of people in need, and to implement ecologically sustainable projects. According to the principles of social entrepreneurship, we are developing projects that create long-term economic benefits for our target groups. This is how we establish sustainable structures together with our local partners and provide help for self-help.

At the moment ex aqua itself contains 11 members, 3 of us traveled to Madagascar in January to make the first steps in initiating our project, together with our partner Reef Doctor. But let me start at the beginning:

On the island Madagascar, the fishing industry is the base of existence for many coastal communities. The urgent problem of overfishing is threatening their already small income of less than $2 per day. Due to the low availability of fish and lack of income, there is lower access to food, causing many people to suffer from malnutrition. A major consequence is that 50% of the children under the age of 5 are affected by anemia. The region of Toliara where our project takes place is the poorest region of Madagascar. Due to long dry periods, there is not much opportunity for growing any vegetables. Another problem is the degradation of the coral reef, caused by overfishing, coral bleaching, and eutrophication, resulting in a loss of habitat for many target fish.

Our solution is the concept of ocean farming. Our vertical farming system grows algae, peppered with seedlings, along ropes. Algae farmers attach these ropes to buoys, which are chained to the ocean floor. From that point forward, the system requires zero inputs, making it the most sustainable form of biomass production on the planet, while sequestering carbon and rebuilding reef ecosystems. The algae are very nutritious and so, they are the perfect addition to the local food, which consists primarily of rice. Another great possibility is created by selling the algae to local restaurants who can use it to earn a fair price.

Since this income would not be enough to support a whole family, we also grow sponges along the algae lines, which lay just over the bottom. Together with the algae they filter the water while giving the reef and fish population a possibility to recover. Sponges also have the advantage of being a great export product, being light and easy to prepare, so our farmers have a minimal amount of labour to perform in exchange for a good income.

Together with Reef Doctor, we have created a prototype to be placed in the ocean right in front of Reef Doctor’s base. Furthermore, we made contact with the women’s association of Ifaty, in order to collaborate on incorporating the algae into their daily diet. We created some cooking experiments on camp (and most of the people liked what we did!), and we also successfully made contact with local restaurants.

The next steps are to supervise the prototype and evaluate its current effectiveness, and to make improvements to the system as best as possible. In the middle of this year we will return to start the actual project with fishermen from the village. Stay tuned for further updates!”

Written by RD volunteer Wiebke Thürlings

Photo credit: James Woodruf & Karin Moehler