Manta residents and visitors
A large population of reef manta rays (Mobula alfredi) occupies the near-shore waters of D’Arros Island. Each of these rays has unique markings on its ventral surface (belly) that enable us to identify different individuals. From this we gather information about how many mantas are using the site, where they spend their time and for how long. We use various photograph and video techniques to identify manta rays at D’Arros, including the deployment of a remote camera set-up at a regularly visited cleaning station. Working with the Manta Trust, we incorporate our data into a broader regional understanding of the population and ecology of these threatened animals in Seychelles.
Since its inception in 2012, the SOSF-DRC has been managed and run by different people in various capacities. Lab managers, research officers and research assistants have been integral to the daily operations of the centre over these years and our long-term projects have been handed on from past to present management.
Currently the SOSF-DRC is run by Dr Robert Bullock and Henriette Grimmel in a joint-management capacity.
The following is a history of past management staff:
- Dr Rainer von Brandis (scientific director) 2006/2012–2016, previously did his PhD on D’Arros and managed the research lab for the previous owners of the island
- Chris Boyes...
Reef Manta population survey
The key objective of this project is to monitor the population size and residency of the reef manta rays that are using the D’Arros site.
The global population of reef manta rays is currently declining, largely due to targeted fishing for the rays’ gill plates. Identifying and understanding the movement patterns, relative population sizes and residency of reef mantas using aggregation areas provides information necessary to inform the protection of these key areas and influence the conservation of the species’ regional populations.
The reef manta ray belongs to the Mobulidae family and is one of the largest ray species in the world. The rays grow slowly and mature late, producing only few offspring. This makes them vulnerable to overfishing and, due to unsustainable fishing pressure across large parts of its range, the species is currently listed as Vulnerable by the International Union for Conservation of Nature (IUCN), which indicates a high risk of extinction.
Scientific research is a critical component of providing effective conservation for this species and the monitoring of individuals over long periods results in important data about population size and trends. Photo identification is a useful means of gathering these data, as collections of photographs of individuals built up over time enable us to estimate the abundance and parameters of population trends.
The key objective of this monitoring programme is met by several specific study objectives:
- To monitor the presence of reef manta rays at a known reef cleaning station;
- To record the presence of reef manta rays around the coastal areas of D’Arros;
- To identify and maintain a record of individual reef mantas using the D’Arros site;
- To utilise data to inform population metrics and conservation.