The warning is not just about sharks. Stingrays are also likely to be something to watch this summer, Lowe said, because the same warm-water conditions that can draw young white sharks closer into California’s waters can also support the stingray populations they feed on.
In 2015, Lowe said researchers saw baby white sharks in Monterey Bay for the first time. Juvenile white sharks generally have a lower temperature limit of about 60 degrees, and Monterey Bay’s spring waters have historically been too cold, often in the mid- to upper 50s.
But waters off Santa Cruz warmed to nearly 70 degrees in 2015, Lowe said. Since then, researchers have documented a nursery aggregation in the Monterey Bay area.
Lowe said the pattern reflects a broader shift: California’s coastal waters have been warming over the past 30 years, making parts of Northern California increasingly viable as nursery habitat for young white sharks.
“This is becoming a perfect storm,” Lowe said. “This is what we think is going to make SoCal the white shark Mecca this summer.”