Deep-Sea Fish With Transparent Eyes

Researchers at the Monterey Bay Aquarium Research Institute recently solved the half-century mystery of a deep-sea fish with tubular eyes and a transparent. The "barreleye" fish Macropinna microstoma was first described in 1939, by the micro-biologists, was well known that its tubular eyes are very good ar collecting light. However, the eyes were believed to be fixed in place and seemed to provide only a "tunnel-vision" view of whatever was directly above the fish's head.

A new research paper by Bruce Robison and Kim Reisenbichler, shows that these unusal eyes can rotate within a transparent shield that covers the fish's head. This allows the barreleye to peer up at potential prey or focus forward to see what it is eating.

Most existing descriptions and illustrations of this fish do not show its fluid-filled shield, probably because this fragile structure was destroyed when the fish were brought up from the deep in nets. However, the two researchers, Robison and Reisenbichler were extremely fortunate, that they were able to bring a net-caught barrelye to surface live, where it survived for several hours in a ship-board aquarium.



In addition to their amazing"headgear", barreleyes have a variety of other interesting adaptations to deep-sea life. Their large, flat fins allow them to remain nearly motionless in the water. Their small mouths proves that they can be precise and selective in capturing small prey.