Marine Research

ReefDoctor’s marine research programme focuses on standard survey techniques that provide reliable information on the status of coral reefs and seagrass meadows, and on artificial reef habitat experiments that might help the local community manage fishing resources within the Bay of Ranobe.

Coral is the foundation of any reef system. The skeletons of corals formed over generations create the limestone structures on which the reef flourishes and grows, while the living corals covering the skeletons are an integral part of the reef’s complex ecosystem. Without the continued health of this part of the ecosystem, coral reefs begin to degrade affecting all the other organisms that make up life on the reef.

ReefDoctor’s current coral reef assessments are sited in three distinct regions within and around the Bay of Ranobe: patch reefs, spur and groove areas, and deep exterior reefs. At present, this encompasses twelve sites including the marine protected areas Reef Doctor has helped create. Surveying these sites on a regular basis provides comparative data on the status of the coral reefs over time and enables ReefDoctor to monitor the effects of marine protection.

Transect surveys
ReefDoctor’s transect surveys are designed to monitor the animals and plants that make up the highly diverse coral reefs of the Bay of Ranobe. A comprehensive marine surveying training programme provided by the Reef Doctor science team is on offer to all volunteers. We provide a series of lectures on fish, coral, algae and invertebrate species identification and have an extensive marine biology library to aid learning. Volunteers will then be taken on numerous ‘point out’ dives and snorkels to practise their marine species identification skills.

Once qualified as a surveyors, volunteers are able to participate in the ReefDoctor ‘s transect surveys and accurately identify and quantify the fish, coral, marine plant and invertebrate populations across a given reef area. By recording life in this way, we are able to analyse the data collected and assess the health of the reef. Over time, this data can be used to monitor changes in fish and invertebrate populations and in coral cover and health. Environmental conditions such as water temperature and water quality are also measured during each survey to contribute to long term records on climate change.

Sedimentation studies
The Bay of Ranobe is the outlet for two rivers in south-western Madagascar. In addition, deforestation inland, local agriculture and residential and tourism development along the coastline means that the risk of pollution and increased sedimentation within the Bay of Ranobe may be having an impact on the overall health of the reef.

To monitor this, ReefDoctor began a one year study of sedimentation within the Bay in 2005. This involved the collection and analysis of sediment from traps situated in our transect survey locations. This allows us to establish what sediment is present and in what quantities. Placing this alongside the data from transect surveys, it is then possible to examine if the level of sedimentation is having an effect on the marine life in the area.

Current sedimentation studies are focusing on the historical sediment input across the Bay using sediment core sampling techniques. Through this we hope to improve our understanding of lagoon sedimentation dynamics and help determine the current risk of sedimentation to the Bay’s coral reef ecosystems.

Coral studies
RReefDoctor has an active and diverse coral research programme. Coral studies have involved quantifying the larval supply of coral species (through the use of settlement plates for analysis by microscope), monitoring the settlement and growth of young corals and investigating annual coral spawning events. New methodologies are also being developed to investigate and monitor the occurrence of coral diseases.

We currently have an extensive coral tagging programme specifically designed for volunteers to participate in. This involves measuring permanently tagged coral colonies in order to establish growth rates and to allow us to monitor this over time. Training will be provided in coral identification, underwater measuring techniques, underwater mapping and digital photographic analysis.

In response to the increasing threat of global climate change we are also developing a new research programme focussing on coral bleaching / recovery patterns within the Bay of Ranobe. This involves developing and implementing coral bleaching specific transect methodologies to document and monitor future bleaching events which, worryingly are expected to become an annual event by the year 2020.

Seagrass surveys
Seagrass surveys 
The lagoon of the Bay of Ranobe is comparatively shallow and home to large areas of seagrass meadows. The function of such meadows is to reduce the impact of waves on the seabed, to help filter sediment from the water, to provide feeding and shelter for many invertebrates and juvenile reef fish and to stabilise bottom sediments. They may also act as a nutrient sink by filtering nutrients and chemicals from the marine environment.

ReefDoctor is an active participant of the global seagrass monitoring network ‘SeagrassNet’. At quarterly intervals throughout the year we conduct a comprehensive surveying and sampling regime across two local seagrass beds. Volunteer assistance is an essential part of this programme with full training provided in seagrass surveying techniques including species identification, transect sampling, scuba surveying protocols and specimen collection/ analysis.

This research programme enables us to establish the current extent and health of the meadows and, over time assess the impact of sedimentaion, pollution and local fishing practises such as beach seine netting on the juvenile fish grounds (fishing by dragging nets through the seagrass on the seabed). In addition the valuable data collected is fed into a large global database (along with over 20 other countries) to document the status of the world’s seagrass resources and form the important first steps in understanding and preserving these valuable habitats.

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