Mark Romanov

The Southern Sea Otter was historically abundant along the California coastline until intense hunting pressures reduced their numbers to near-extinction levels. But now the otters are coming back, and with them they bring the potential for drastic change to the modern-day economics and ecology of the Santa Barbara Channel.

Marine biologist and cameraman Rick Rosenthal has been filming in the ocean for decades, but one spectacle has eluded him and other filmmakers, until now. It is a vast “vertical migration” that happens every night, in which billions of animals rise up from the depths. Rosenthal captures the often bizarre and still unchartered life forms that make up the largest animal migration on the planet.