Surfers and beachgoers in the Mexican Border city of Tijuana were witness to a rare spectacle Monday, involving killer whales that appeared just outside the surf zone and began to harass dolphins.
Eastern Tropical Pacific killer whales, which are found off Mexico and Central America, are not commonly seen off the northern Baja California coast--especially so close to shore.
Carlos Bravo, a photographer who captured the images for use with this story, said lifeguards and locals said they "have never seen anything like it."
A report from Alan Williams on the Orca Network Facebook page quoted locals as saying, "This has never happened."
The killer whales are not believed to be "transient" orcas from California. Those mammals, which prey on dolphins and other marine mammals, have never been documented in Mexican waters.
Eastern Tropical Pacific killer whales, which have not been separated into distinct ecotypes, also are known to prey on marine mammals. They’ve been documented in U.S. waters, as far north as Catalina Island, according to killer whale researcher Alisa Schulman-Janiger..
The killer whales were traveling in two groups of between four and seven, and were spotted less than 100 yards off Playas de Tijuana, just south of the U.S.-Mexico border.
Williams stated: "A surfer and some others reported that they 'ate a dolphin' and described them holding it in their mouth and 'throwing it about,' which sounds [like] typical behavior. I didn’t see it, but the gulls and scavenger birds were swarming to feed on some leftovers of something, and there are or were plenty of dolphins here."
Bravo said he received a call at 9 a.m., and arrived at 9:20. He saw only one of the two groups and said he watched them tossing a dolphin, presumably teaching younger members of the pod how to hunt and kill, until about 9:45.
Both reports said the killer whales traveled west, toward the Coronado Islands, before disappearing from view.
Williams wrote: "A surfer in black wetsuit was in the water, and three large orcas approached him in a semicircle to about 30 yards/meters, and each in turn did a 'spyhop' maneuver, wherein they surface in a high vertical posture and hover high up for a few seconds--perhaps threatening?
"Or perhaps just to look, or to announce their presence or claim territory. It was quite beautiful, and he got out quickly."
Researchers are hoping that by looking closely at photos they'll be able to match at least one individual with others in a photo-identification catalog of Eastern Tropical Pacific killer whales.
NOAA has identified about 240 individuals.
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