When a massive school of anchovies swam uncharacteristically close to the California shoreline last week, they couldn’t have picked a better location: right outside the University of California, San Diego’s Scripps Institution of Oceanography.
It’s no surprise that these marine-loving professors and students immediately jumped into the water to take footage of this rare occurrence and also take samples, and they were fortunately able to catch footage for the rest of us to see this phenomenon. And they weren’t the only ones intrigued: A California sea lion and a leopard shark dove right into the anchovy mass.
Anchovies swim in large schools to avoid predators like sharks, seabirds,and a variety of other marine mammals. The particular swarm was massive, stretching about one mile long and estimated to contain between 10 million to more than 1 billion fish, according to The Huffington Post. While it’s rare for a school of anchovies to be this large, it’s even more unusual for an aggregation to come so close to shore with water temperatures at a warm 74 degrees, as anchovies typically seek cooler waters. Scripps professor David Checkley suspects that the anchovies were driven closer to the beach because offshore waters in the area have been warming more rapidly than the water inshore recently, which could be related to the looming El Nino.
Scripps scientists say they haven’t seen a school like this in more than 30 years, as anchovy populations have been low for the past 20 years. According to Checkley, anchovy populations are increasing thanks to overall cooler temperatures in the Pacific caused by the Pacific Decadal Oscillation.
Check out footage of the event from Scripps below.