It was about six feet long, he said, and tough to follow as it swam over dark patches of reef that camouflaged its shape. Just after 10:30 a.m., he spotted a small white shark swimming north. Rex paid close attention to that zone the sharks often follow the same route just beyond the crashing waves. Dolphins surfaced in the waves, and sea lions worked the line behind the breakers, hunting for fish. For several hours, Rex piloted the drone over the site, seeking a quick, dark shape in the surf.
Surfers lined up along the low waves, distance swimmers paddled to an outer buoy, and kids splashed at the water’s edge. The water was calm, but the overcast sky cast an opaque glare onto the surface, making it hard to see creatures below. Rex flew the drone in long transects off the coast, looking for sharks in the surf, while Anderson communicated with colleagues on the boat to alert them to any sightings. That’s what the researchers saw Wednesday, as they searched for sharks off Del Mar. Given that, the young sharks are often hungry and skittish. They may also select shallow water to avoid adult white sharks, which will happily eat their young. “We have lots of stingrays in our water.” “The most abundant food source and easiest for them to catch is stingrays,” Lowe said. (Patrick Rex / Shark Lab, Cal State Long Beach)
“We look at how many sharks are in close proximity to people, and we also look at how sharks behave when they’re close to people,” Lowe said. In addition, they fly drone surveys off beaches in San Diego County and elsewhere to record sharks as they move among people in the water. The team has also developed a buoy with a real-time sensor that will alert lifeguards and scientists by text each time a white shark swims by. They collect the data monthly and share with the lifeguards, Lowe said. Researchers have installed buoys that record the tag transmissions. Those change from year to year recently, there have been large aggregations off Santa Barbara, and fewer in San Diego, possibly because of red tide events, he said. White sharks congregate at “hot spots” including Santa Barbara, Ventura, Santa Monica Bay, Long Beach/Huntington Beach, and the San Clemente/San Onofre area, said Patrick Rex, a graduate student at the Shark Lab. So far this year, they have tagged about 30, most of those off the coast of Ventura and Santa Barbara, some off the Central Coast, and just one at Del Mar. The team has been tagging white sharks at beaches along the coast of Southern California, using acoustic transmitters that record their movements. (Jarrod Valliere / The San Diego Union-Tribune)
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