We have updates from our manta tagging project with Conservation International (CI)!
Last year, we worked with CI and Indonesian organisations the Ministry of Marine Affairs and Fisheries (MMAF)’s elasmobranch conservation initiative and the Indonesian Institute of Sciences (LIPI) on a 10-month manta tagging project from September 2014 to June 2015.
In the study, we managed to tag 33 manta rays, including eight pregnant reef manta rays, with custom-made GPS-enabled satellite tags. Among the mantas tagged, 29 were Reef Manta Rays while the remaining four were Oceanic Manta Rays.
We covered four regions of Indonesia–Bali, Raja Ampat, East Kalimantan, and the Komodo National park.
During the study, we discovered the first manta ray nursery to be recorded in Southeast Asia and managed to track detailed manta ray migration route in the four regions in Indonesia.
First manta ray nursery in Southeast Asia to be discovered
Our major discovery in the study was finding the first known manta ray nursery in Southeast Asia.
By tracking the movements of one of the pregnant female mantas and juvenile manta rays, we discovered a cluster of newborns and juvenile rays in Wayag Lagoon in Raja Ampat.
From this, we concluded that this area is used by reef manta rays as a primary nursery and pupping ground where they give birth to young.
We also found out that juvenile manta rays in the nursery sometimes go outside of the lagoon into the deep waters around the area. However, they will always come back quickly to the safety of the shallow Wayag Lagoon.
Government taking action to preserve the manta nursery
With the discovery of the manta nursery, the Indonesian government has started on conservation actions.
Juvenile manta rays have the tendency to stay close to the surface and risk propeller strikes from speedboats.
Therefore, Raja Ampat Marine Protected Area Authority will be introducing new regulations to restrict speedboat use within the lagoon to prevent injury and disturbance to the young mantas.
The new regulations are expected to be implemented within the next six to 12 months.
Detailed manta ray migration route discovered
By tagging and tracking the manta rays, we were able to record detailed route of manta ray movements. The study of these animals’ travelling pattern is necessary to the implementation of an efficient conservation management of the species as relevant parties now know where the mantas are and thus where exactly to take necessary actions.
We found that the manta rays in Southern Indonesia regularly move between tourism viewing areas in Bali and Komodo National Park and also in regions where manta rays have been hunted in the past.
Previously, tracking manta rays travelling in Indonesian waters between islands was based on photographic identification work by local environmental organisations.
With the manta tagging project, we were able to confirm the routes with records of the GPS-enabled satellite tags which provide a detailed route of the migration pattern.
We also confirmed that the manta rays moving across known hunting grounds in South Lombok and off Southern Sumbawa, were the same Mantas which were spotted by many tourists in Nusa Penida and Bali. .
Stopping manta ray hunting
The data provides evidence for the Indonesian government to increase enforcement in the respective areas to stop manta ray hunting. The government had begun working in this direction with its 2014 national law protecting manta rays in Indonesian waters.
Indonesia is an important place for the manta species: Both the Reef and Oceanic Manta Rays live in Indonesian waters. Indonesia’s Raja Ampat is the one of the only places in the world where both species can be found.
Indonesia has the second largest manta ray tourism industry in the world with an estimated annual value of over US$15 million. Manta-focused tourism provides important benefits to local communities in all four of the tagging study regions. These communities now hold manta rays in high esteem with some villages adopting the animal as their local icon.
Head over to our partner Conservation International’s blog to find what more about the results of the manta tagging project.