Thousands of dead sardines and mackerels washed up on a beach in Hakodate, Hokkaido, Japan, covering about 1 km of coastline. The cause of this mass die-off is still unclear, and local authorities have asked residents not to consume the fish. Researchers believe that the fish may have been chased by predators, exhausted from lack of oxygen, and washed up on the beach by the waves, but more investigation is needed to determine the exact cause. Neighboring countries, particularly China, are paying close attention to this event in light of concerns about the discharge of contaminated water from the Fukushima nuclear power plant.