It’s relatively easy to spot when and where a pregnant animal gives birth on land. But in the sea, it’s a whole different story.
Over the past few decades, researchers studying the elusive great white shark have pieced together a picture of their underwater lives: The adults seasonally travel between a remote region of the Pacific Ocean—dubbed the White Shark Café—and their feeding grounds in Central California and Mexico.
But where do females give birth, and where do the offspring grow up?
“We don’t know whether [the sharks] pup in-shore or off-shore,” explains the Aquarium’s Director of Collections John O’Sullivan. “We don’t even know whether they pup in American or Mexican waters.”
But in a paper recently published online in the journal Fisheries Research, scientists have revealed a new piece of the juvenile white shark puzzle. The study—an international collaboration between researchers at the Ensenada Center for Scientific Research and Higher Education (CICESE); Monterey Bay Aquarium; California State University, Long Beach; and other institutions—revealed that Bahia Sebastian Vizcaino, a warm lagoon on the coast of Baja California, is a nursery area for newborn white sharks.
John O’Sullivan, the Aquarium’s Director of Collections, was in Mexico on a mission. A young white shark equipped with an electronic tag had traveled over 650 nautical miles south from its release point in Monterey Bay, and the tag had popped off somewhere along the central coast of Baja California. The tag contained a complete data set documenting the shark’s movements and physiology since its release, and John aimed to recover it.
Instead his guide, a local fisherman, led John to a shark graveyard.
A grisly grimace
Sometimes, commercial and sport fishermen accidentally ensnare juvenile white sharks off the coasts of California and Mexico. But locals in some communities consider it bad luck to discard the unmarketable parts, such as the heads, back into the ocean. Instead, they deposit these shark parts at dump sites in the Mexican desert.
In central Baja, just north of Guerrero Negro, John and a team of local Mexicans encountered hundreds of shark heads, in various stages of decay. Some were fresh; others were rotting. Some had skin that was dry and well-preserved—in other words, mummified—in this arid location.
Many of us would turn away from that gruesome sight. But John and his colleagues looked into the mouths of the shark-head mummies and saw an opportunity.
In the coastal habitats of Baja California, life thrives on the edge of desert sands and sapphire seas. Our newest special exhibition, ¡Viva Baja! Life on the Edge, opened on March 19, featuring the incredible creatures and habitats of this narrow Mexican peninsula.
But we’re not just exhibiting the splendors of Baja’s rugged 800-mile coastline. We’re also taking a lead role, working with colleagues here and in Mexico, to safeguard it.
Close ties with Mexican researchers
The Aquarium works with several universities in Baja—including El Centro Interdisciplinario de Ciencias Marinas (CICIMAR) and Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE)—to study key marine species, such as white sharks and and mahi-mahi (also known as dorado).
“There’s been this growth in how we approach other countries and also meet our needs as an aquarium,” says John O’Sullivan, the Aquarium’s director of collections
We’ve been tagging juvenile white sharks in Southern California since 2002, documenting seasonal migrations of these young fish between coastal waters in the United States and those on Baja’s Pacific coast.