The tag that we recovered from the juvenile white shark released by the Monterey Bay Aquarium on January 16 shows that he high-tailed it west from the 50°F waters of Monterey Bay to warmer waters in the 60° F range. Then he headed south. In 90 days, he swam more than 2,200 miles overall, ventured up to 700 miles offshore, dived as deep as 1,000 feet, and finally ended up over 1,000 miles from Monterey Bay. (Mike Castleton, a GIS specialist in the Block lab at Hopkins, put together this image of the track.)

The shark was captured offshore near Santa Monica Bay on August 17, 2006 and placed in an offshore pen. Through the careful efforts of a husbandry and research team led by John O’Sullivan, Chuck Winkler and Chris Lowe, the shark was eventually moved to the aquarium two weeks later after he began feeding. He spent 137 days at the aquarium. Under Manny Ecurra's careful feeding regime, he grew from 5 feet, 8 inches and 103 pounds (August 31, 2006) to 6 feet, 5 inches and 171 pounds.

While the tag was on the shark, it gathered data every 5 seconds. Over the last month we have been analyzing and mapping the tag’s data. This is what we found: The shark spent his days near the surface, with occasional deep dives to around 660 feet – a pattern typical of adults when they are traveling to and from the California coast to offshore hotspots between California and Hawaii. Here's a one-minute animation of his track put together by Chris Perle, a graduate student in Barb Block's lab here at Hopkins.

At night, he avoided the surface. Instead, the shark oscillated up and down far beneath the waves, with an average depth near 250 feet. He made its deepest dives at dawn and dusk.

The white shark’s last known position – just before the tagged popped off – was at an important seamount at the entrance of the Sea of Cortez, the Cabrillo Seamount, known in Mexico as “Bajo Cabrilla.” Seamounts – underwater mountains that don’t break the surface – are important habitat and foraging grounds for many open-ocean animals. Here's a 45-second 360-degree look at the spot the tag popped off, also put together by Chris Perle.

The tag popped up at the entrance to the Sea of Cortez, at the southern end of the known range for northeast Pacific juvenile white sharks. Juvenile and adult white sharks have been captured inside the Sea of Cortez, but we don't know whether they are born there or migrate in and out. So it’s very interesting to see this juvenile show up right at the entrance.

This shark’s journey clearly shows that, like many migratory animals, sharks don’t recognize international boundaries. It underscores how important it is to work closely with our Mexican colleagues to make sure we have adequate protection for the species. Our collaborator, Fernando Marquez. of Mexico’s Instituto Nacional de Pesca, has also tracked a juvenile white shark captured inside the Sea of Cortez.

These data add to information gathered from other tracking tags on juvenile white sharks to build a more detailed picture of where young white sharks in Southern California and Mexican waters are going. This is critical information to determine where fisheries managers need to focus efforts to protect juvenile white sharks. Although white sharks are protected in California and in Mexico, the juveniles are often caught accidentally, as “bycatch” by commercial fishermen fishing for other species.