The giant oarfish is the longest bony fish in the world, reportedly reaching lengths of up to 56 feet from tip to tail, and spawning legends of sea serpents, though recorded evidence falls short of that length.
The oarfish, Regalecus glesne, has no teeth and feeds mainly on plankton, jellyfish and squid. It can often be seen hanging vertically underwater, facing the surface and waiting for prey to pass in front of the light of the sun.
Lead researcher Mark Benfield said the fact that the oarfish didn't flee from the ROV's light could mean it has few natural predators.
Some footage was taken by an ROV (remote-operated vehicle) operated by the SERPENT Project (Scientific and Environmental ROV Partnership using Existing Industrial Technology). Other observations came from other sources.
In August 2011, an ROV operated by Mako Technologies was conducting seafloor and water column biotic surveys as part of the Deepwater Horizon oil spill. The ROV was being pulled back up when a single oarfish was observed at a depth of about 200 feet.
Five different encounters were filmed between 2008 and 2011 at depths of up to 1,600 feet, and the researchers' observations are published in the Journal of Fish Biology.