Manta rays are widely distributed, migratory, and have unique spot patterning on their underside that can be used to identify individuals. MantaMatcher is the first global online manta ray database, managing manta ray sighting and identifications worldwide. Any diver or snorkeler with a camera can take and upload a manta identification photo. Researchers can also upload and organize individually identified manta rays in the regional populations they are managing. MantaMatcher also promotes collaborations by way of cross-referencing different study sites. Scientists can now examine if populations are shared between neighboring countries, examine regional and long distance movements, and examine the lifespans of manta rays.
A sophisticated algorithm is used to match manta identification photos automatically. The algorithm works like facial recognition software for manta bellies. By automating much of the identification process researchers can match mantas regionally, and even globally, with ease. Researchers will ultimately be able use sightings data to determine the abundance, trends, movements, and population structure of manta ray populations at individual aggregation sites across the globe.
Uploads to MantaMatcher have already contributed to our better scientific understanding of these species. A paper on manta migrations in Indonesia, using data sourced from MantaMatcher, was instrumental in achieving protection for mantas across all of Indonesia's waters. Data from MantaMatcher were also used as scientific justification for Convention on Migratory Species listing of reef mantas (Manta alfredi) in November 2014.
You don't need to be a researcher to contribute. Any diver or snorkeler with a camera can identify an individual manta ray. By uploading your manta identification photos, and information about your manta encounter, you too can help global manta ray research and conservation.
Marshall AD, Holmberg J (2018) MantaMatcher Photo-identification Library https://www. mantamatcher.org Downloaded on YYYY-MM-DD.
Did you know that the natural spot patterns on the underside of manta rays can be used to distinguish between individuals like a fingerprint? Researchers are now using these natural markings to keep track of different population and examine their movements around the world. Contributing to this ongoing work is a way for the public to engage in what we like to call “Citizen Science”. We cannot do this alone and we are asking for the public to help us solve some of the mysteries of mantas by adding photos to our global database.
Below we explain a little more about the different species of Manta and outline the best ways to photograph these animals in the world and upload your photos to our website.
Currently two different species of Mantas are recognized, and it will be important to note which species you have observed. Luckily the two species can be visually differentiated and the following guide will help you distinguish between Manta alfredi and Manta birostris.
|Fig 1. Differences between manta species|
Reef mantas (Manta alfredi) can be found in all three of the world's major oceans but are most commonly encountered in the Indian Ocean and south Pacific. Key aggregation sites include: Hawaii, Australia, Komodo, Maldives, Yap, Palau, Bali, and Southern Mozambique.
|Fig 2. Dorsal surface of Manta alfredi|
|Fig 3. Ventral surface of Manta alfredi|
The giant manta (Manta birostris) is the most widely distributed manta ray and is found in all three of the world major oceans. This species is commonly encountered at offshore islands and seamounts. Key aggregation sites include: Southern Brazil, Ecuador, Thailand, Egypt, Southern Mozambique, and Mexico (Pacific Ocean).
|Fig 4. Dorsal surface of Manta birostris|
|Fig 5. Ventral surface of Manta birostris|
|Fig 6. Remnant spine in Manta birostris|
To make matters slightly confusing, two distinct colour morphs have been identified in manta rays, black mantas and white mantas. A genetic disorder causes these different colour variants and both conditions are rare.
Black mantas, or melanistic mantas, have an entirely black topside, and a predominately black undersides except for a variably sized white blaze along its mid-line.
White mantas, or leucistic mantas, have a reduction pigment making their skin appear lighter, even white.
Don't worry if you have doubts about identifying the animal you encountered or uploading your ID shots. If you do not feel comfortable assigning a species or coluration type when you upload your photo, our trained staff will do it for you. Simply click on “unsure” or “unknown” when prompted.
|Fig 7. Colour morphs in mantas|
Determining the sex of a manta is usually quick and easy. If you have taken a good ID shot of the standardized area, you will be able to ID the animal's sex from this photo. If not, check your other photos to see if you can see the pelvic fins. Pelvic fins are the two small fins located at the rear of the animal by the tail.
|Fig 8. Determining sex|
Female manta rays do not have any external reproductive organs so all that you will see in the image will be fins. Because there are no organs to judge by, determining the maturity status of a female ray can be difficult. If the individual was visibly pregnant or possessed reproductive scars (bite marks obtained during mating) on either or their wing tips then they can be classified as mature.
|Fig 9. Sexual maturity in females|
Male manta rays do have external reproductive organs, call claspers, that protrude off of these pelvic fins. Immature males will have small claspers and mature males will have large claspers that protrude past the edge of the pelvic fins.