**Update: On Friday morning the shark's position was to the north past San Miguel Island
A great white shark tagged in 2012 at Guadalupe Island, west of Baja California, is closing in on Southern California and is the first known adult white shark from the Mexican island to have entered California waters.
The adult female white shark, which was tagged by Michael Domeier and the Marine Conservation Science Institute, on Thursday had passed Cortes Bank and was closing in on San Clemente Island (see graphic posted below). Cortes Bank is about 100 miles west of Orange County. Guadalupe Island is 165 miles west of Ensenada.
The adult female shark (pictured above) is named Arden Grace.
"Have you got a SCUBA trip lined up at San Clemente this weekend? If you do you might want to watch your back," MSCI posted on its Facebook page.
Another post reads: "This is a strange time of year for her to be in the coastal region. We've never had a female in our cold winter waters at this time of year, and we've never had one of our Guadalupe white sharks swim to California...
"She's headed towards San Diego now! Will she make it or turn around?"
(Those who wish to follow the movements of sharks tagged at Guadalupe can do so via the MCSI's Expedition White Shark app, available through iTunes.)
Great White sharks in the northeastern Pacific are known to have site fidelity during the fall and early winter to either Guadalupe Island or Northern California elephant seal rookeries, such as the Farallon Islands west of San Francisco.
During this time of year, however, the vast majority of adult white sharks from both aggregation regions are hundreds of miles offshore, in areas stretching as far as Hawaii.
Interestingly, sharks tagged at Guadalupe Island have never visited Northern California white shark aggregation sites. In 2008, an adult female white shark tagged near the Farallon Islands was tracked to Guadalupe.--Pete Thomas