Swimming with manta rays is almost a therapeutic experience I would say.
Being in the water with these animals makes you forget about anything else.
The interaction with this animal just clears up your mind and opens up your heart and
your soul and you just want to be down there as long as you can and sometimes
you have the feeling that mantas feel the same way about us.
So they want us to remain with them for as much as possible.
Manta rays are undoubtedly among the most
charismatic creatures of our ocean, they are on top of the list of animals that
any ocean lover wants to see and swim with, but like many species in the wild
on our planet they face a number of serious threats. They are increasingly
fished and their populations are at risk.
So this project aims to establish the
factors that are responsible for the annual fluctuations in breeding, why
animals breed in certain areas and not others to help inform the
conservation of these species both in the Maldives and other areas of the world.
In particular we we're using a newly developed underwater ultrasound
machine. So this machine is able to scan and visualize the internal structures of
manta rays without any contact with the animal it uses saltwater as the contact
medium. It's a light and portable machine which will allow scuba divers to
approach the animal and obtain images of particularly the reproductive tract
without causing any disturbance or stress to the animals themselves.
Ultrasound examination of wild manta rays have only been attempted a very few
times and that was done with big, bulky ultrasound machines - very difficult to
maneuver underwater the ultrasound examination were made by making contact
with the animal and the innovative aspect of this project is that it uses a
completely new ultrasound machine which is very small light and portable and is
mounted on a 3d printed rig with handles which makes it very easy to maneuver underwater.
To actually scan a manta ray, we dive close to a cleaning station down to
about 20-30 meters in sometimes difficult conditions - ocean currents, low
visibility. We approach the animal from above so that the animal doesn't feel
the presence of the diver, extending our arm in order to get the probe as close
as possible. While above the animal we are adjusting our movement to minimize
the impact and distress to the manta.
We then position the ultrasound scan about
four or five centimeter from the animal targeting the left side of dorsal fin
which is where the reproductive structures such as the ovaries
and the uterus are visible.
The sonogram or images are recorded on a mobile phone
and then analyzed in the lab.
Our research project is taking place in the Republic
of Maldives. The Maldives has a largest population of reef manta rays in the
world, sightings of these animals are very
reliable consistent and thus allow us to obtain ultrasound examination of the
same individual multiple times throughout the entire gestational period.
So we were able to determine the stages of maturity and when animals are
becoming reproductively active, the stages of pregnancy, the development of
the fetus and importantly whether animals maintain that pregnancy and
actually give birth to a live animal.
Understanding some of the fundamental
details about their reproductive strategies enables the populations to
survive and hopefully flourish and our hope is th at this research project will
contribute to that knowledge
in order to preserve the species for future generations.