Barreleye

• GeneralIts head is a transparent dome, and its tubular eyes look upward from inside it.
• For decades the existence of the dome went unknown, because it always broke as specimens were hauled up in the nets, and it was not documented intact until 2009.
• Its tubular eyes can rotate from looking upwards to looking forwards, which lets it track prey right into its mouth.
• The two dark spots above its mouth that look like eyes are in fact olfactory organs.
• Its green tubular eyes sit inside a transparent, fluid-filled dome covering its head; what look like eyes from outside are in fact the nostrils.
• For seventy years it was believed it could only look upwards: in 2009 MBARI showed with submersibles that it rotates its eyes forward to feed.
• It is thought to position itself beneath the tentacles of siphonophores and steal the prey caught there; the transparent dome would protect it from the stinging cells.

Skeleton type

Vertebrate - internal bony skeleton (bony fish)

Habitat and environment

The mesopelagic zone (600-800 m)

Gestation / incubation

It is thought to be a pelagic spawner: eggs and sperm are released into the water and the eggs drift with the currents. There is no direct observation to confirm it

Sources consulted: Wikipedia (es): Macropinna microstoma · FishBase, Macropinna microstoma · Recopilaciones sobre Macropinna microstoma · MBARI · FishBase · A-Z Animals, ficha Barreleye · MBARI, observaciones con ROV en el canon de Monterey

Best time: It lives hanging almost motionless between 600 and 800 m deep, with records from 400 to 2,500 m, in the temperate waters of the North Pacific: Monterey Canyon, Japan, the Sea of Japan and as far as the Bering Sea. It uses its large fins to hold steady, with its eyes pointing upwards