Tag Archives: Manta birostris

Manta giving birth or intestinal eversion?

By Angelina Cecchetto on 9 February 2013

Photography: ©2013 Martin Ureta. All Rights Reserved.

Photography: ©2013 Martin Ureta. All Rights Reserved.

Following the great feedback I received from the last post “The first breathtaking photo of a giant oceanic Manta Ray giving birth??” it would seem that the picture could well show a case of what is called “gastro-intestinal eversion” where the manta actually ejects the lower part of its intestine out of the cloaca in order to clean its intestine from indigestible debris.

This is an event which has so far been rarely recorded in the wild. One other case has been recorded in 2007 at a cleaning station in waters off Maui[1].

Since I am no marine biologist I will leave it to the specialists to decide whether the picture shows a manta giving birth or everting its intestine. In any case this is a very rare and lucky shot!

What this information leads me to wonder is whether the regularity at which the mantas evert their intestine has been increased by the anthropogenic pollution factor? It would also be interesting to know what sort of impact this has on the mantas habits and behaviors if any.

It would also seem that the shot could be of a Manta alfredi rather than Manta birostris, this is still to be defined with other shots. The differentiation between Manta alfredi and Manta birostris is fairly recent and dates back from 2009[2]. In fact Manta alfredy, also known as Reef Manta Ray and Manta birostris are both part of what is called the “genus Manta” family and they can easily be confused. It would seem that manta birostris do not display markings between the gills.

What is pretty certain is that the situation of the mantas alfredy is also critical. The same over fishing threats apply to both species and the population is drastically decreasing. The IUCN[3] categorized the manta rays as “Vulnerable” in between the “Near Threatened” and “Endangered” species and states that “Overall, the rate of population reduction appears to be high in several regions, up to as much as 80% over the last three generations (approximately 75 years), and globally a decline of 30% is strongly suspected.”

As I mentioned in the previous article, there are various factors that led to this critical state of affairs: overfishing, very low fecundity rate and anthropogenic pollution.  It would seem that in the wild female mantas give birth to a single pup every 2 to 3 years cycle. When we add this factor to the overfishing trends we can easily understand that populations are being easily depleted.

Whether this picture shows a Manta birostris or a Manta alfredi and whether it is showing a birth or a gastro intestinal eversion (I leave it to the knowledgeable marine specialists and scientists to decide), the important message is that Mantas are in danger and they need a strong global protection. I am hoping that this picture will raise awareness, open up discussions, ideas exchange and humbly contribute towards global mantas protection.

Angelina Cecchetto

[1] “Intestinal eversion in a free-ranging manta ray” by Springer-Verlag 2007. http://www.himb.hawaii.edu/sharklab/Clark_et_al_manta%20intestine%20eversion.pdf

The first breathtaking photo of a Manta Ray giving birth??

By Angelina Cecchetto on 7th February 2013

Photography: ©2013 Martin Ureta. All Rights Reserved.

Photography: ©2013 Martin Ureta. All Rights Reserved.

When my friend and Film Maker Martin Ureta came to the Maldives for a dive holiday he was far from imagining that he would be the amazingly lucky and first ever photographer of a giant oceanic manta giving birth in its natural environment!

Despite a growing number of scientific studies on manta populations very little is known thus far about the giant oceanic Manta ray also known as Manta Birostris. No one has ever seen them give birth so far. So it would seem that Martin is the first person to have ever photographed a Manta Birostris in the process of giving birth in its natural environment, and this happened during the first week of January 2013! The shot was taken during a dive in the southern part of the Ari Atoll in the Maldives in a dive spot famous for spotting mantas. During the dive a group of 3 Mantas Birostris were twirling over the shallow reef to feed to the delight of the group of divers observing their graceful underwater moves. The divers were all mesmerized by the spectacle and couldn’t believe their luck to have spotted the mantas and have them twirling over them for some magical minutes. Martin was busy enjoying the show and capturing this underwater ballet on camera. None the divers, nor their guide noticed anything particular happening with the mantas during the actual dive but when they came back to the island and viewed the pictures we noticed something unusual in one of the manta’s pelvic area. I immediately thought this might be the unbelievable capture of a manta birth but I am not a marine biologist.

When he returned from holidays, Martin contacted The Manta Network[1] in California to get an opinion on what is actually happening on the photo. Robert Aston, The Manta Network Executive Director shared the photo with Dr. Robert Rubin who is one of the foremost experts on Manta Birostris and from their very enthusiastic feedback, it would seem that the picture is indeed the first picture of a Manta Birostris giving birth.

We would like to use this picture as a flagship picture to defend mantas and especially the giant oceanic mantas. We hope this picture will create the awareness that mantas are some of the most peaceful and graceful underwater creatures. Very little is known about them so far but all the studies being led are highlighting a drastic decline in their populations. According to the IUCN[2] “The rate of population reduction appears to be high in several regions, as much as 80% over the last three generations (approximately 75 years), and globally a decline of 30% is strongly suspected.”

The IUCN categorized the manta rays as “Vulnerable” in between the “Near Threatened” and “Endangered” species. There are a various factors that led to this critical state of affairs.

The first main threat comes from fishing as mantas are highly valuable in international markets and in particular in Asian markets. As Africa Geographic’s Science Editor Tim Jackson[3] mentions in his article entitled “Myths about manta rays”:  “In traditional Chinese medicine, it is believed that the gill-rakers of mantas and other rays cure chickenpox and alleviate high blood pressure. They don’t!”

The fact that mantas are easy to spot from the surface due to their large size, and easy to fish out because of their slow swimming speed and the fact that they don’t avoid humans, make them a very easy prey for many fishing boats.

Another important factor to understand is mantas reproductive cycle. Although there is a lot to be learnt still, it is thought that Mantas Birostris have a gestation period of one year and generally give birth to a single pup at a time. It is still not quite clear whether females have a pup per year or one every 2 years. At this rate it is important to understand that if the fishing rate is higher than the manta rays reproductive rate, they will soon be extinct.

Another factor to mention is the anthropogenic factor such as water warming and pollution which indirectly affects mantas habitat although it is pretty difficult to evaluate in which measure.

To conclude I would say that in the light of all of the above it appears quite vital that worldwide measures are taken as soon as possible. Some countries have already applied strong measures to protect mantas as the UICN states, mainly the United States, the Republic of Maldives, the Philippines, Mexico, Ecuador, Australia and New Zealand. Whilst this is a great start, Mantas are in danger and need a strong global worldwide protection.

Mantas are some of the most peaceful and graceful underwater creatures I have been given the chance to see. It would be a lot more than just an “awful shame” to loose such a magical underwater specie in the name of an unfounded cure property.

Angelina Cecchetto