The Giant Pacific Mantas are Back!



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TBC

In one of the most incredible turnarounds in recent times in our increasingly threatened world´s oceans, the story of the giant pacific mantas (Mobula birostris) is one of the most amazing and mysterious.

The Gulf of California or Sea of Cortez as it is also known, as well as the Pacific side of the peninsula are no newcomers to remarkable recoveries and empowering stories of entire ecosystems coming back from the brink of complete loss.

The oldest such story is perhaps the magnificent recovery of the gray whales and the protection of their birthing lagoons on the Pacific shores of the Baja. Twice pulled from the jaws of extinction the gray whale population has a made a full recovery.

A more recent experiment in ecosystem recovery is the unequaled success of the comeback of the Cabo Pulmo coral reef habitat. Once severely threatened by overfishing, ghost nets as well as anchor or trawling damage this northernmost coral reef in the Pacific Ocean was near collapse.

Local fisherman converting their personal economy towards eco-tourism coupled with conservation efforts by several NG0s helped to turn the situation around. Both local success stories were the result of years of hard work and the combined forces of all those concerned about our oceans.

This story of a species surprising recovery starts out differently. The mantas are back, and no one really knows why. The return of these majestic flying carpets is an incredible joy to local divers, tourist providers, conservationists and of course manta researchers. However, this last group is also completely mystified.

“The last confirmed sighting in Isla Cerralvo was in 2002,” according to Pablo Ahuja of Manta Mexico. ¨They have been gone for around 16 years and we are still looking for an explanation for their disappearance and now they have returned, literally out of the blue.”

Manta Mexico was formed as a research project by Ahuja, a marine biologist, in 1999 along with Dr. Felipe Galvan of CICIMAR (Centro Interdisiplinaria de Ciencias Marinas). Dr Galvan is one of the leading experts in Mexico on sharks as well as their relatives the rays and skates. The project began as a study of the behavior of the manta rays and later expanded to look at residency, distribution, gender balance and interaction using photo ID techniques.

“At the time Photo ID was cutting edge stuff with the mantas,” explained Ahuja. Photo Identification of wild species as opposed to tagging or marking animals has become the preferred technique of study and animals as diverse as whales, zebras, jaguars, elephants and even sharks. The animals can be identified as individuals simply by maintaining a series of photos. Almost like a Facebook or Instagram of the wild kingdom.

The Photo ID allowed the Manta Mexico to proceed very quickly in establishing a minimum population and gender balance. The mantas all have distinctive spots on their ventral side and by using SCUBA the researchers simply swam under them and took pictures as the graceful rays navigated the waters around Cerralvo Island. The spots serve as a “fingerprint” to identify individuals.

“Once you are under the mantas you can also tell if they are male or female and they all seem to enjoy the bubbles released from breathing with the SCUBA gear,” added Ahuja.

The researchers identified 52 individual mantas in the 2001 and 2002 seasons which ran from June through November. Then in 2003, the giant rays suddenly disappeared.

¨We looked and looked, maybe 4 or 5 times a week but found nothing,” said Ahuja. The Manta Mexico research team was backed up by SCUBA divers from around the world that flocked to this now famous manta dive location. No one saw a manta for years until a few sightings in 2017 and then a full-blown return this year.

“We saw one in June of this year and we were shocked,” explained Erick Higuera, a marine biologist who works with Manta Mexico and another organization called Pelagic Life. “And then they just kept coming and coming.” Higuera is one of the initial researchers locally and has since been studying mantas in the Revillagigedo Islands some 400 miles south of Cabo San Lucas.

“So far we have identified 14 individual mantas in the last few months and thanks to the original work done earlier this century we can say for sure these are all new animals to the area.”

The mantas of Cerralvo are juveniles ranging from 6-12 ft. (2-4 meters) and have not yet reached their full size of 27 ft. (9 meters). The researchers are still looking for an explanation for their strange disappearance and miraculous return. Theories range from some traumatic event such as an orca attack, harpoon fishing or even mass capture in fishing nets, that while not killing all the animals, would have been enough to convince the surviving population to go elsewhere.

“The truth is we don´t know,” said Ahuja. “These are juveniles and they may use the area as a nursey in the way that the whale sharks do.” The life history of mantas is one of the great unknowns of the natural world.

¨While we try to figure out their disappearance and resurgence we are also trying to protect them,” said Arturo Bocos, a marine biologist with the Manta Mexico team and ECO, a reef conservation project. “We are encouraging best practices for interaction with the mantas and the reborn tourism industry. Obviously, no one should touch or ride them but we have also documented that anchor lines regularly harm the mantas,” concluded Bocos.

The majestic animals seem to not be able to spot the ropes and injure themselves or even catch in the anchor lines snapping them off the boats only to later drag away the line, anchor and chain as they become hopelessly entangled. To avoid this Manta Mexico is encouraging all visitors to not anchor at the site and at the same time, they can also protect the corals in the area.

The Manta Mexico team has expanded to include researchers from Tiburon Ballena Mexico, ECO, Pelagic Life, the World Wildlife Fund and Pelagios Kakunjá. These last two organizations have helped provide funding to place satellite and acoustic tags on several mantas this year.

“The acoustic tags send a message to receivers we have placed on several reefs in the area, so we will know more about the mantas habitat use,” explained Dr. Frida Lara. “The satellite tags will give us data in the future about the mantas long-term movements, the depths they prefer at night and their global position.”

¨This project has come a long way,” concluded Ahuja. “With the help of a strong team of biologists, the latest technology and a great group of professional photographers we hope to be able to answer some of the harder questions and find ways to protect these beautiful animals and their habitat.”

For more information on best practices, responsible tour operators, donations or general questions please send an e-mail to mantamexico@hotmail.com or call 612 154 9859.

All photos courtesy of Alex Double

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