Improving Coral Cultivation in the Bay of Ranobe

Older generation fishermen in Ifaty report that the Bay of Ranobe used to be carpeted with corals just a few decades ago. However, today, environmental degradation facilitated by intensive human activities and mass coral bleaching events has wiped out numerous coral communities in the bay. Alongside the implementation of various management measures to address the causes of this reef degradation, in 2012, Reef Doctor established a reef restoration programme in attempt to directly revitalise the once flourishing seascape. This is done primarily through the setting up of coral nurseries with the hope of later transplanting the reared corals to the degraded reefs. However, this task has encountered several challenges. In particular, the survival of small coral fragments is threatened by a whole suite of environmental stressors, such sedimentation, bioerosion, and elevated summer temperatures. As a result, the success of the coral nursery in the Rose Garden marine protected area has been variable over the years and it has only remained small-scale to date.

reef degradation

We have recently begun work to address issues hindering the success of the coral nursery. We realised that (1) corals currently being reared in the coral nursery might not necessarily be optimal candidates for cultivation (2) Rose Garden might not necessarily be the best place for setting up a coral nursery. To address these two fundamental questions: the Science Team set up an experiment led by Science Officer Martin Wong and Research Assistant Jack Farley with the following objectives: to determine (1) how different coral species perform in the nursery (indicated by their survival and growth rate) and (2) how these performance indicators vary on a spatial scale across the bay. The answers to these objectives will guide us in selecting suitable coral species to be reared and suitable sites to set up additional coral nursery grounds with the potential to expand the project’s scale in the near future.

The experimental set up to address these questions is in fact quite simple: we used rebars, cement, and used water bottles to create the final product, the Water Bottle Table, pictured below (Design credit given to Martin’s former laboratory in the University of Hong Kong):

Coral fragments are attached to the caps of water bottles, which can be “opened” so that we can measure the weight of each individual coral fragment overtime. The water bottle table is attached to the bottom with zip-ties and rebar poles.

Different species of Acropora corals are attached to the water bottle tables, which are then place at different sites across the bay. We will be monitoring the corals over the coming few months to obtain data on the increase (if any) in length and biomass of the fragments. We would also like to observe how different species at different sites cope with the summer elevated temperature, i.e. if any bleaching occurs and how they recover if indeed bleached. Therefore, in principle, in less than a year’s time, this experiment will provide us important information on where to rear different coral species so that we can increase the productivity and effectiveness of future coral nurseries. Stay tuned for further updates on our water bottle table experiment and coral nursery development.

Written by RD Science Officer Martin Wong

Photo credit: Jack Farley & Karin Moehler

Planting Propagules on World Mangrove Day

July 26th is International Day for the Conservation of the Mangrove Ecosystem. Along with coral reefs and seagrass, mangrove ecosystems are amongst the most threatened ecosystems on Earth. The Reef Doctor Honko Project works with local communities and authorities to conserve and restore mangrove ecosystems in the Bay of Ranobe.

World Mangrove Day is celebrated every year in our area, as many communities depend on mangroves for their livelihood.

This year, Reef Doctor played a part in two events that took place separately in Ambondrolava and Andrevo and were attended by the Director General of Partnership and Sustainable Development to the Ministry of Halieutic Resources and Fisheries, the Chef de Région Atsimo-Andrefana, DRRHP and DREEF.

The authorities departed Toliara in the morning to arrive in Ambondrolava, where they would make their first stop. Ambondrolava is the village where the Reef Doctor Honko project is established and since the beginning of 2017, 15 hectares of mangrove of 3 different species have been planted. World Mangrove Day has been celebrated in Ambondrolava every year since 2008. The event was organised by VOI Mamelo Honko and Reef Doctor and more than 300 people from neighbouring villages attended. A total of 4.5 hectares of mangroves of 2 different species, Ceriops tagal and Avicennia marina, were planted. Aside from the planting, dance contests as well as men and women football games were organised. World Mangrove Day is a great tradition that people really enjoy as well as an event to raise awareness on the importance of mangroves.

After Ambondrolava, the authorities made their way to the second site of the day, Andrevo. There, a ceremony and planting event were organized by the Direction Régionale des Ressources Halieutiques et de la Pêche (DRRHP), the Direction Régionale de l’Environnement, de l’Ecologie et des Forêts (DREEF), the Cellule des Océanographes de l’Université de Tuléar (COUT), Indian Ocean Trepang (IOT), Ocean Farmers and Reef Doctor.

Almost all Reef Doctor’s volunteers and interns went to Andrevo for the planting event. Some were already there since the day before as they attended a sea cucumber sale in the evening. Arriving quite early for those leaving camp in the morning, waking up quite tired after the short night for those who spent the night in Andrevo, everyone gathered at the place where the ceremony would take place. The wait was lengthy, but curious and cheerful kids coming to interact with the volunteers and interns passed the time! Lindsay, one of our volunteers, had the great idea to introduce us one by one to the kids and they shouted each name with lots of laughs after she pronounced them. A local women, dressed all in violet, started dancing confidently all by herself, putting on a nice show for everyone. Ale, the brother of one of our aquaculture intern, who came to Reef Doctor to document our work through photography, didn’t wait long to join the woman to dance, driven by the rhythm.

After the arrival of the authorities, everyone took their place and the speeches started. Lala, the head of our aquaculture department, was tasked with the translation of the speeches to the volunteers and interns. In between speeches, the women’s association of Andrevo entertained the crowd with their lively dance and songs!

After the speeches, it was time to head to the plantation site in the mangroves for the main event.

Everyone together, high authorities, mayors, president of fokontany, staff, volunteers and interns of Reef Doctor, men, women and children started walking towards the mangrove. Feet in the muddy mangrove soils, everyone took a handful of propagules and started planting them straight into the ground up to one third, as explained by Josepha before the planting.

Once the 4 hectares completed (2 hectares had already been planted by the communities), everyone made their way back to the ceremony site to have a drink and a few snacks while listening to frenzied gasy music. While most volunteers and interns sat down to relax after the planting, one of them tried her hand at gasy dance with some children, before being joined by a woman who seemed bewitched by the music!

It was in a joyful atmosphere even if everyone was tired, then we said our goodbyes to the people and the village and hopped on our taxi brousse to head back to the Reef Doctor camp.

Written by RD Communication Officer Karin Moehler

Photo credit: Margot Chapon


New Swim-Through Tourist Attraction at Rose Garden MPA

Two weeks ago, our Science Team added a new feature to the Rose Garden Marine Protected Area (MPA): a swim-through tunnel! Although, currently only a bare metal framework, we hope that it will soon become colonised by interesting and colourful invertebrates and algae, which will in turn attract reef fish. The idea of this tunnel originally came from our Director, Emma Gibbons, who envisioned it as a tourist attraction, offering divers a unique swim-through coral reef experience, which we hope will increase visitor numbers to the MPA. The ultimate goal is to increase MPA profits for the local fishermen’s association, FI.MI.HA.RA, vital for the sustainable management of this reef area, and boost ecotourism revenue for local tour guide piroguiers who have committed to a more sustainable marine-based livelihood. We also intend to utilize it as a coral nursery as part of our reef restoration programme. Below Science Officer Martin Wong describes its construction and installation…

The 5 m x 3 m rebar swim-through tunnel was proudly constructed by the local community in Ifaty and contains a few marine life cut-out decorations embedded on its surface. The structure is very heavy, requiring six people to carry it on land. As you can imagine, its size and weight made it quite a difficult task for us to transport it from the beach out to Rose Garden in our relatively small boats. However, Anne Furr, owner of Mangily Scuba, kindly lent us one of her boats large enough to carry the entire structure.

The boat trip out to Rose Garden was a slow and steady ride, giving enough time for the Science Team and our Dive Officer Louis (who kindly helped us in this project) to pose for a photo, taken by ex-Reef Doctor Science Officer Lucy Fisher. Lucy is founder of Reef Guru, a coral reef eco training and consulting company and our new collaborative partner in reef restoration. It is great to welcome Lucy back in Ifaty and we are very grateful for her recent assistance in our reef restoration programme.

Thirty minutes later, we finally arrived at Rose Garden. We carefully tipped the structure over the edge of the boat so that it would roll over and eventually hit the sandy bottom of ~5 meters depth, which was exactly how it went down (high-five with the team!). Now the easiest part behind us, it was time to move the structure underwater. To do so, we attached two flotation devices (lift bags), one at each end to give the structure an extra lift. Then, we removed our fins, placed our hands on the bars, and started moving one step at a time. Even with the help of the lift bags and the power of eight arms, the structure still felt quite heavy and we felt just like we were walking on the moon with slow and small steps despite all the efforts we put in!

As the tunnel was dropped quite far from the target site, to avoid impacting the marine life on the patch reefs, we had to navigate our way underwater. This was not the easiest task when we are arms were overloaded, so we did end up exercising in the water much longer than we should have due to a few detours here and there! However, after 15 minutes or so, we finally reached our destination. We then settled the structure on a sandy patch and secured the base by hammering down rebar hooks. Now everything was in place, we performed the first swim through, which was a great experience that we are sure divers are going to love!Tunnel9


In the near future, we will be transplanting live coral fragments onto the tunnel. By doing so, not only will the tunnel be decorated, but it can also serve as a nursery ground for coral cultivation as part of our active reef restoration programme. We will also cooperate with local dive shops to advertise this tunnel so that more divers and snorkelers will be able to enjoy this swim-through experience. In doing so, we hope that these visitors will become more aware of our efforts in local coral reef restoration and conservation. Stay tuned for further updates on this project and our latest reef restoration progress!

Photo credit: Lucy Fisher, Beth Dickens & Karin Moehler