When people hear the word "migration," they think of animals that move from a feeding area to a breeding area and back each year. But the greatest migration on Earth happens twice every night. The movement is largely vertical and performed by plankton followed by predatory fish, squid, octopus and other species that have acquired a taste for plankton. The migration starts deep in the waters of the ocean at sunset. As they move, the plankton nibble...
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Nature