The huge oarfish has been filmed by scientists operating a tiny submarine by remote. This may be the first time this fish is filmed, or even seen, in its natural environment. The species might have been caught on camera at a depth of 765 meters during a research mission off the coast of western African in 2007, but marine experts haven’t been able to positively identify the creature in that video.

Oarfish are large, elongated fishes belonging to the family Regalecidae. The family contains four species of which the largest one is the famous King of Herrings (Regalecus glesne), listed in the Guinness Book of World Records as the longest bony fish alive today. The largest known King of Herring was 17 metres (56 ft) in lenght.

Normally, this deep-dweller is only encountered when dead ones are washed ashore or when dying specimens are brought up to the surface by fishermen.

The research crew was therefore happily surprised when an oarfish suddenly showed up in front of their camera.

We saw this bright vertical shiny thing, I said ‘are they lowering more riser?’ as it looked like they were lowering a huge pipe,” said Mark Benfield from Louisiana State University, Baton Rouge, USA, one of the scientists working at the Serpent Project in the Gulf of Mexico.”We zoomed in a little bit and we said ‘that’s not a riser that’s a fish!’ As we approached it retreated downwards swimming tail first in a vertical orientation as the ROV followed. What was interesting about the fish was its swimming behaviour. It moved by undulating its dorsal fin in waves that propelled it backwards at quite a good speed.”

Early estimates measure the fish at between 5m and 10m in length, which roughly equals 16-33 feet.

The Serpent Project is a collaboration between marine researchers and energy companies such as Petrobras, Chevron and Shell and involves the use of remotely operated vehicles (ROV’s) to explore depths to which it would be extremely dangerous to send a human. Responsible for the project is the National Oceanography Centre in Southampton, USA.

The King of Herrings is believed to be the creature behind the ancient myths about gigantic sea serpents. It has a prominent dorsal fin, almost like the continous spikes of a fairytale dragon.