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North America’s biggest marine protected area — Mexico’s Revillagigedo National Park — may have been nearly seven times smaller if not for shark-tracking data collected by researchers and alumni from ��������.

Above: Retired adjunct professor Peter Klimley tags hammerhead sharks.

The park, known as the “Galapagos of North America,” protects more than 57,000 square miles around the Revillagigedo Archipelago, a UNESCO World Heritage site composed of a string of four volcanic islands about 300 miles southwest of the Baja Peninsula.

The designation, announced by Mexico in October 2017, prohibits mining, fishing and tourism development on or near the islands. This protects key habitat for an abundance of sharks, giant manta rays, humpback whales, dolphins, fish and migrating birds.

From 6 miles to 40

“It used to be protected 6 miles around every island,” said Mauricio Hoyos-Padilla, who took part in shark-tagging research as a Ph.D. student with Mexico’s Centro Interdisciplinario de Ciencias Marinas. “But thanks to all the information we gathered about the connectivity between all these islands, we were able to protect 40 square miles around the islands.”

Between 2009 and 2010, �������� adjunct professor Peter Klimley, postdoctoral scholar Alex Hearn and Hoyos-Padilla joined a tagging expedition to place acoustic receivers on the area’s sharks with National Geographic, which chronicled the work in the documentary TV series Shark Men.

Hoyos-Padilla and James Ketchum, Ph.D. ’11, formed the nongovernmental organization Pelagios Kakunja in 2010 to continue the shark-tagging effort.

Sharks on the move

The park’s design and designation was heavily informed by Ketchum’s Ph.D. dissertation, which analyzed the expeditions’ acoustic and satellite telemetry data from 2009 to 2015 to see how the sharks were using the islands.

It showed the sharks not only relied on the 6 miles around each island, but rather on large swaths of connectivity — extending out 100 miles in some cases — between the islands. Using scalloped hammerhead movements as an example, the study showed their use expands to 40 nautical miles around each island and recommended that be the standard for a marine protected area there. The Mexican government ultimately agreed.

Ketchum’s study suggested designs for a marine protected area that would take this high level of connectivity into account. The first design was proposed to the Mexican Commission of Natural Protected Areas in 2014 and included in the UNESCO Heritage site documentation. Another, more expanded design was used by a group of lawyers in Mexico City and Pew Charitable Trusts to push for the creation of the Revillagigedo National Park. The researchers were invited to the signing decree of the new national park in Mexico on Nov. 24, 2017.

“I’m very excited,” Ketchum said. “It shows all these years of work have been useful for something.”