We overheard that in Scripps Pier located in La Jolla, California, people noticed massive splotches on the sea and thought they were just traces of oil spill. The footage of the “oil spill” dated back in July 8, 2014. That same year, the Scripps Institution of Oceanography at the University of California, San Diego published a report claiming that what they found was a rare phenomenon that occurs every 30 years. Apparently, those weren’t splotches of oil but a massive school of anchovy congregated in the shallo water. Because of their density, they looked as if they are dark bands.source:youtube