The Manta Ecology Project
Until as recenntly as 10 years ago very little was actually known about manta rays and this project was initiated to study the behavioural ecology of mantas from observations in the field.
The project began in November 2001 whilst we worked as dive guides in the Maldives. High on the diver’s wish list was a dive with manta rays (Manta alfredi is the species we commonly see in the Maldives) so every week a number of dives were made at known cleaning stations in order to observe them. We were not sure whether we saw the same mantas every week or different ones so we developed an method to identify them individually based on the spot markings based on the ventral side of each manta (see Compare Mantas for more information on identification).
In 2005 the project was formalised as as a research project under the supervision of Newcastle University and resulted in a Ph.D award. The project included development of an ACCESS database to store the burgeoning data on mantas identified. By 2014 there are over 2300 mantas recorded and the database continues to grow by about 200 new mantas each year, seen at both established sites which we continue to visit plus a large number of new sites we have identified using our understanding of where mantas go. It appears that there are fairly fixed populations of mantas in each atoll, but the individuals move around between the various cleaning stations and feeding areas. We have now been sighting the same mantas for well over 10 years
We now know there are two species of manta ray, the Alfred manta (Manta alfredi) and the larger, more pelagic, giant manta (Manta birostris) shown in photo below (photo: John Rochester). There may even be a third species, endemic to the Caribbean.
Manta birostris is found across the world in tropical waters and occasionally travels into colder water with regular reports as far north as New Jersey USA and possibly from Newfoundland and as far south as New Zealand. It grows to at least 6.8m disc width (DW) and has a distinctive cartilaginous mass just behind its dorsal fin which covers a spine. Manta alfredi is smaller, growing to about 5m DW and is reported mainly from tropical reefs.
Current research projects include investigations into the social behaviours of individual mantas, including whether they form groups and close associations, agonistic behaviours between individuals to determine priority at cleaning stations and co-operative behaviour whilst feeding.
Medium term projects are investigating the movements of both individual mantas and populations of mantas. We are proud to be involved in the IUCN Maldives Monitoring and awareness programme and are busy training up marine biologists and diving instructors and dive masters to collect data on the manta rays they observe. By increasing the number of reports of encounters and the area from which the observations are being made from we hope to significantly increase the number of manta rays sighted. Our target is to include the majority of the entire Maldives manta ray population in our database so we expect to include over 5000 individuals by the end of 2015. To help us achive this target we are now collaborating with Manta Matcher so that photographs from encounters can be processed automatically.
Our other research projects continue, including a study on cleaning ecology, the ecology of the isolated population of Addu atoll and a study of juvenile mantas in sheltered lagoons.
We encourage interested divers to come and support our research by joining one of our specific "Research Weeks". Check out the News and Events page for the most up to date information. We are also looking for funding to help us complete a Maldives wide migration studies project. If you can help sponsor this project please contact Anne-Marie
If you would just like to enjoy some manta pictures see Photo Gallery