Scientists from the Monterey Bay Aquarium Research Institute (MBARI) filmed a barreleye fish (Macropinna microstoma) in 4K for the first time during an October 2026 expedition off Central California. The fish was observed about 90 kilometres offshore, near Monterey Canyon, at a depth of roughly 600 metres.
Rare deep-sea encounter
The team used the remotely operated vehicle Doc Ricketts from MBARI’s research vessel David Packard. Research Specialist Shannon Johnson spotted the fish as the vehicle was returning to the surface. Researchers watched it for about 20 minutes and adjusted the lighting to show its transparent head shield.
This was MBARI’s 11th encounter with the species in nearly 40 years of exploration, spanning about 7,000 ROV dives and more than 41,000 hours of footage. It was also the first barreleye sighting filmed from the David Packard. Senior Scientist Steven Haddock noted that historical drawings often lacked the fish’s delicate transparent head feature because specimens did not retain it. The encounter was an unexpected find on the “Diving Deep for Delicate Drifters” expedition, which focused on gelatinous animals.
Important Facts for Exams
- Protective head dome: The barreleye’s transparent dome protects its sensitive eyes from the stinging cells of siphonophores, which it is believed to raid for food.
- Rotating eyes: The barreleye can turn its eyes from an upward to a forward-facing position as it rotates its body to feed.
- Green eye pigments: Green pigments in the barreleye’s eyes may filter sunlight from above, helping it detect the bioluminescent glow of animals overhead.
