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 cameras 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.
Having grown up in rural Western Australia, I have always been surrounded by wildlife and I cannot remember a time when I wasn’t in awe of the natural world. My passion for the ocean and marine life was sparked when I was five years old and my family took the first of many trips to the Ningaloo Reef. I could not get enough of snorkelling the reefs and exploring the intertidal pools to see what new creatures I could discover. It wasn’t long before everyone knew the response they would get when they asked me, ‘What do you want to...
I have been fascinated by the natural world all my life and growing up on a farm in south-western UK provided me with a seemingly limitless supply of weird and wonderful creatures to discover. I always knew that I wanted to make studying animals my career, but it was only when I was given a tropical fish tank at the age of 11 that my passion for the underwater world began. From that moment forward I would say ‘I want to study fish!’ when asked what I planned to do when I grew up. True to my word, I progressed...
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 the 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:
There is a very lucky population of manta rays that lives at D’Arros Island in the Seychelles. These mantas not only live in a relatively pristine habitat, but are also safe from fishing. This gives researchers a unique opportunity to learn about how these intriguing animals live when they are free from human influence.