Marine Research

ReefDoctor’s marine research programme focuses on standard survey techniques that provide reliable information on the status of coral reefs and other associated tropical marine habitats. ReefDoctor’s marine research programme consists of the following:

Coral Reef Monitoring

ReefDoctor has been monitoring the status of the Bay of Ranobe’s coral reef system since 2003. The well established long term surveying programme monitors various environmental and ecological parameters across the Bay to provide an assessment of the impacts of anthropogenic and natural pressures on coral reef health. In particular, a major threat to the integrity and survival of the bay’s coral reef that requires close monitoring, is the shift from coral to algal dominance. This is occurring across many shallow reef areas within the lagoon as a result of sustained nutrient loading and increased fishing pressure.

The surveys are conducted across 5 core sites encompassing a selection of reef zones; patch reefs, barrier reef flats/slope, exterior spur and groove reefs, and in two marine reserves. ReefDoctor has developed a survey methodology specifically for the Bay of Ranobe adapted from those of CoReMo (www.COREMO.com).

Both members of ReefDoctor’s science team and trained volunteers take part in SCUBA transect surveys collecting data on the following:

• Indicator Reef Fish. Underwater Visual Census (UVC) methods are conducted along belt transects to collect abundance data on fish that have been selected for monitoring on the basis of their ecological and economic significance.

• Benthic Composition. The Point Line Intercept (PIT) method is used to obtain percentage covers of hard coral, bleached/dead coral, soft coral, macroalgae, rubble, sand etc.

• Indicator Invertebrates. Abundances of invertebrates that have been selected for monitoring on the basis of their ecological and economic significance (e.g. sea cucumbers, sea urchins, crown of thorns starfish, giant triton shells) are recorded along belt transects.

• Environmental Parameters. Data is also collected on several physical / oceanographic variables such as water temperature, air temperature, wind, currents, cloud cover, turbidity etc.

The data collected and analysed over the long term enables ReefDoctor to monitor changes in the coral reef condition over time and ensure management decisions are scientifically well informed.  The impacts of marine protection can also be assessed by monitoring deviations from the marine reserves baseline data and from comparison with unprotected sites. The results of these surveys are also fed back to government departments, relevant regional / international coral reef organisations and also to the local community to help them better manage their bay’s coral reef resource.


Seagrass Surveys

ReefDoctor has been an active participant of the global seagrass monitoring network ‘SeagrassNet’ since October 2007.  Along with other SeagrassNet teams worldwide (in over 20 countries) ReefDoctor conducts synchronous quarterly sampling of the Bay of Ranobe’s seagrass meadows. The monitoring protocol consists of a comprehensive set of surveying and sampling procedures (such as the deployment of temperature/light sensors, specimen collection and processing, quadrat samples, canopy height measurements, photographic analysis, sediment coring, water testing and GPS mapping) which take place across permanently established transects along the seagrass bed.

Seagrass beds are ecological and economically valuable habitats. They act as an important habitat for a large number of organisms, stabilize bottom sediments, act as hydrodynamic barriers reducing wave energy and filter coastal waters of nutrients, contaminants and sediments. Seagrass meadows are also of particular importance to the Vezo communities as they provide the basis of the productivity of numerous subsistence fisheries.

Unfortunately, due to their location on land-sea interface, seagrass beds are subject to many anthropogenic impacts including eutrophication, sedimentation, human development, fishing net trawling and like most other marine ecosystems are also threatened by global climate change. These surveys are carried out in order to be able to document the status of the seagrass resources in the Bay, monitor changes in their health and form the important first steps in understanding and preserving these valuable habitats.


Coral Studies

Coral is the foundation of any reef system, providing food and a structured habitat for many marine organisms. Without the continued health of coral, reef degradation will occur resulting in the loss of an extremely productive and diverse ecosystem, impacts to subsistence reef fisheries, loss of diving tourism related revenue and an increasing threat of coastal erosion. Coral reefs within the Bay of Ranobe are under imminent risk of collapse through climate change induced pressures, algal overgrowth and sedimentation.

Previous coral research programmes at ReefDoctor have focussed on coral spawning events, recruitment and artificial reef habitats. At present, ReefDoctor currently has two active coral research and conservation programmes:


Coral Bleaching Watch

Coral bleaching events and the consequential reef degradation are becoming more frequent with increased intensity of extreme climatic events. A rapid visual assessment methodology has been developed to quantify the extent of temperature associated coral bleaching (McClanahan et al. 2004). This methodology was incorporated into ReefDoctor’s science program in 2010 and is conducted annually between January–March (the period when coral  bleaching may occur; if the seawater temperature exceeds 27.5 °C for a period of more than 2 weeks) and then again in April-July, to monitor the extent of bleaching recovery. The ultimate goal of this research is to conduct long term monitoring of coral bleaching events in the Bay, determine the resiliency of the reefs under the threat of global climate change and develop effective resilience based management strategies. The data collected from this program is also submitted to a centralised database for the West Indian Ocean region.


Coral Gardening

ReefDoctor has implemented a long-term reef restoration project within the Bay of Ranobe, in order to assist the natural recovery process of the degraded and damaged coral reefs. We adopt a two step restoration protocol known as ‘coral gardening’. The mariculture of small coral branch fragments (broken coral pieces of Acropora species that have been recovered from seagrass beds) takes place in a nursery afloat in mid-water at the Massif des Rose marine reserve. The coral fragments are maricultured in the nursery to sizes suitable for transplantation (which takes between 100-400 days), with regular cleaning maintenance by the ReefDoctor science team to ensure that they are not overgrown by algae. Nursery grown coral colonies are then transplanted onto degraded reef sites to stimulate natural regeneration and recovery. This project is being conducted in association with the local fishermen’s association, FI.MI.HA.RA in order to engage them in the restoration of their marine habitats and resources.