Scientists have captured rare footage of the barreleye fish, a deep-sea creature known for its transparent head and distinctive green eyes, during an expedition in the Pacific Ocean.
Researchers from the Monterey Bay Aquarium Research Institute (MBARI) spotted the fish about 55 miles off Monterey Canyon. The team observed it at a depth of around 1,970 feet and recorded it for 20 minutes, capturing its unusual features in high-definition footage.
The researchers were exploring the ocean aboard the vessel David Packard, using a remotely operated vehicle called Doc Ricketts to observe and collect deep-sea creatures when they encountered the fish.
Known scientifically as Macropinna microstoma, the barreleye is around six inches long and inhabits the ocean's twilight and midnight zones, between 2,000 and 2,600 feet below the surface. It is rarely seen because of its deep-sea habitat. In 40 years of exploring the ocean depths, the MBARI team had encountered the species only 10 times before.
A window into its unusual anatomy
The fish's most striking feature is its transparent head, through which its green eyes can be seen. This unusual structure has long made it a fascinating subject for researchers.
Steven Haddock, the expedition's senior scientist, described it as an amazing creature that looked as though it had been imagined by a child.
He explained that historical drawings of specimens collected in fishing nets often showed the fish without its transparent head covering. As a result, it was difficult to recognise that the illustrations represented the same species.
Haddock said seeing the fish alive, with its transparent covering intact, was a real privilege.
The 20-minute observation gave researchers a rare opportunity to document the barreleye in its natural deep-sea habitat and capture its distinctive appearance on camera.
