Juvenile great white sharks exhibit distinct behavioral responses to approaching storms, according to a recent study by scientists from UC San Diego’s Scripps Institution of Oceanography and the Shark Lab at California State University, Long Beach (CSULB).
During Hurricane Hilary in August 2023, researchers tracked 22 juvenile white sharks off the coast of Torrey Pines and Del Mar in northern San Diego. Using acoustic tags, the team monitored the sharks' movements before, during, and after the storm. The study, which is the first to document storm-response behavior in white sharks, found that more than half of the monitored sharks temporarily left their nursery grounds.
Many of these young sharks sought refuge in more sheltered locations, such as La Jolla Cove, which offers access to deeper waters due to a nearby submarine canyon. "We believe that some were seeking shelter from the storm," said co-author Chris Lowe, leader of the Shark Lab at CSULB, referencing the sharks observed in the less wave-active cove.
One juvenile shark was recorded swimming to a depth of 433 feet, an action believed to be an attempt to escape rough surface conditions. The researchers also noted a significant drop in sea surface temperature in the sharks' nursery area, from 68 to 57 degrees Fahrenheit in a single day, preceding the storm. This temperature change may have signaled the sharks to move, as adolescent great whites are thought to be more sensitive to cold than adults.
The study highlights that shark behavior during storms is not uniform, with individuals responding differently, much like human reactions to extreme weather. "It makes sense that not all sharks did the same things, in much the same way people respond differently," said Lowe. "It’s a key survival characteristic that humans seem to share, too."
As climate change escalates, understanding how marine species, including white sharks, respond to extreme weather events is increasingly critical. White sharks and humans share the same coastal waters, making studies on shark behavior vital for both conservation efforts and safe ocean use, according to Brice Semmens, a Scripps marine ecologist and co-author.
In related research, scientists at the University of Delaware are exploring the potential of using sharks to predict hurricane intensity on the East Coast. By attaching electronic tags to sharks such as shortfin mako, blue sharks, smooth hammerheads, and juvenile great whites, they collect data on ocean temperature and salinity. This information could provide insights into the "cold pool" in the Mid-Atlantic, a factor that influences hurricane intensification.
