May 27-June 5, 2022

Dr. Deni Ramirez Macias
Ultrasound Pregnant Whale Sharks and Manta Rays
$3600 per person, quad occupancy


Last November, I joined Dr. Deni Ramirez Macias to help her tag and identify mantas, and to ultrasound a whale shark. It was a trip of a lifetime!

I have done many dive trips but to have a purpose in helping with important research to protect these magnificent creatures added a special purpose to my diving experience.

I loved learning from Deni’s lectures and just hanging out and talking around mealtimes. She’s so authentic, passionate, and approachable.


About the Trip

Join the fantastic crew of the Quino El Guardian, world-renown whale shark researcher Dr. Dení Ramírez Macías, and her team as we return to attempt to ultrasound pregnant whale sharks and manta rays in the Archipielago of Revillagigedo!

The whale shark (Rhincodon typus) and the giant manta ray (Mobula birostris) are filter feeder elasmobranchs. In some countries, these species constitute a fishing resource, while in other countries, they are more valuable as an opportunity to attract tourism. Therefore, the sustainable exploitation of these species depends significantly on the knowledge of their populations. This knowledge is minimal.

Both species are especially vulnerable due to their biological characteristics as they are slow-growing, late to reach sexual maturity, and found in small populations. All of this is why the IUCN Red List recognizes these species for the Conservation of Nature.

In the Archipielago de Revillagigedo, we can find giant manta rays and whale sharks that enable Dr. Dení Ramírez Macías and her team to study these charismatic giants. Their studies have focused on demonstrating the presence of pregnant females in both species showing that this is a critical habitat for these elasmobranchs and requires a top priority for its conservation.

Our expedition will focus on obtaining an ultrasound in females of both species to corroborate that they are pregnant and to evaluate the degree of the embryonic development. This information will help to substantiate the theory that these waters are necessary for reproduction and to strengthen the protection of habitat for the conservation of the species. A second goal will be to place a satellite tag to see her movements.

Our goal is to use the regular itinerary for diving in Socorro, knowing that we will be open to using any opportunity that presents itself to ultrasound whale sharks and manta rays.

Deni will also be doing presentations throughout the trip. These presentations will include but not be limited to:


1. Following the Giants: Whale Sharks
2. Conservation Biology of the Whale Shark
3. The Giant Manta Rays from Revillagigedo
4. Ultrasound on Mobula Rays
5. I3S software for whale shark and giant manta ray photo identification


Dr. Dení Ramírez-Macías is the director of Whale Shark Mexico, a passionate conservationist, powerful advocate for the ocean, and pioneer in her field. As a scientist, her innovations both above and below the sea have led to the founding of multiple NGO’s, numerous scientific publications, advanced the careers of her students, and has inspired future generations to take an active role in ocean conservation. As a scuba diver, she is applying scientific research methods to her work underwater, most recently by ultra-sounding pregnant whale sharks and manta rays in an effort to learn more about their reproduction. Her work is being used to create three protected areas in Mexico. Deni's research has taken her around the world and her research has been part of several international films including the National Geographic Discovery Chanel. Deni was inducted into the Women Divers Hall of Fame in 2020.

To book your space, email Susan at

In 2020, Deni was aboard Quino el Guardian and performed a successful ultrasound on a pregnant whale shark in Revillagigedo.  Check out this video!