The waters off La Jolla in San Diego were filled with anchovies in early July, as a massive school of the fish migrated near shore, leading to a spectacular sight recorded by researchers from the San Diego-based Scripps Institution of Oceanography (SIO). The event gained nationwide media attention.

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According to Scripps, the giant school of California anchovies, also called northern anchovies, Engraulis mordax, formed a dark band off La Jolla, near the Scripps pier, swimming quickly through the area.
In an interview with CNN, SIO Professor Dave Checkley said, “It is rare to see so many anchovy abutting the surf zone. More usually, schools are seen hundreds of yards to many miles offshore.” The surf zone is the area in which waves break on shore and humans normally swim.
Schools of anchovy can range from hundreds to millions of fish, said Checkley, who gave this school “a very rough estimate” of between 1 million and 100 million anchovies.
“In my approximately 30 years at the SIO starting in 1970, I’ve not seen this before,” Checkley said.
It is unclear why the large school moved into shallow waters off the coast, although changing ocean temperatures may be the cause of the anchovy influx. The North Pacific is currently transitioning into a cooler state, which is favorable to anchovies, said Checkley. He added that, while this particular phenomenon is unusual, anchovy populations naturally fluctuate on the scale of decades.
They’re still studying the phenomenon, and members of the Scripps Marine Vertebrate Collection have gathered samples for the study.
Scientists weren’t the only ones taking note of the army of anchovies. The California sea lion, which preys on the small fish, seemed “happy as a clam,” Checkley said.
“Human beach-goers and surfers similarly [were happy], enjoying a rare sight of an abundance of schooling fish within easy swimming distance,” said Checkley. “For those able to snorkel among the anchovy, it is a wonderful experience…fish, fish, fish!”
A few leopard sharks were observed feeding on the anchovies.
According to the National Oceanic and Atmospheric Administration (NOAA), northern anchovy is the species found and commercially harvested off the West Coast. Today, it is used as valuable bait fishery. Its European counterpart, Engraulis encrasicolus, is the anchovy best known in the culinary world.
According to Wikipedia.org, “As sardine populations declined in the Pacific during the 1940s and ’50s, fish packers in America started canning the more abundant local anchovies. Total hauls increased over this time from 960 tons in 1946 to 9,464 tons in 1947 and peaking at almost 43,000 tons in 1953. From 1949 to 1955, they were restricted for all uses but bait fish in California. In 2010, reported American hauls totaled 2,100 metric tons. Most California anchovies today are fished for use in animal feed and as bait fish.” 
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