'Multimillions' Of Anchovies Spotted Off California Coast

There was quite a sight off the coast of La Jolla, California, yesterday: what looked like a giant dark ink stain, or an oil spill, moving and pulsing like it was alive — because it was.

It was a massive school of anchovies – "multimillions" of them. Scientists at the Scripps Institution of Oceanography say it’s the largest such school that’s been seen off the coast of California in 30 years.

David Checkley, a professor of oceanography at the Scripps Institution of Oceanography at the University of California, San Diego, studies anchovies and went swimming with the school.

"It was fish, fish, fish!"

David Checkley

"It was fish, fish, fish! There were fish in front of me, below me, to the sides, and behind me," Checkley tells Here & Now's Jeremy Hobson. "And they were beautiful."

Schools of fish generally swim aligned in one direction. At the edge of the school, the fish create what looks like a hard boundary or, as the professor explains, a beautiful "cliff."

Beauty aside, questions remain about the sudden appearance of the mass of anchovies.

Cooling Pacific waters over the past decade may be a factor, says Checkley, but not a definitive reason for the mysterious anchovies manifestation. In recent years, there has been an increase in cool water-loving anchovies while their sardine cousins, who prefer warm water, have decreased.

"This may be just the start of seeing more anchovies over the next decade, or two decades," Checkly said. "But why they're right up against the surf zone, is something I just can't explain."