| THE HANDSTAND | MARCH2009 |
What a catch!
The amazing deep-sea
fish with a transparent head
http://www.dailymail.co.uk/sciencetech/
25th February 2009
This amazing barreleye fish really does have eyes in the back of his head.Accustomed to living in the pitch-black of the deep sea, the animal has developed this unique and incredibly useful ability to spot predators trying to sneak up on it, as well as potential food.
The discovery came when the fish was filmed by marine biologists trying to solve the 50-year-old mystery of how it uses its eyes.
For years scientists believed its eyes were fixed and it only provided a view of what was directly above its head.However it now emerges that over time the Macropinna microstoma has evolved so its eyes are able to look out in different directions from within a transparent shield.
Eyes front: The barreleye fish has developed the unique ability to move its eyes inside its head so it can spot predators and food in pitch-black seas. While its body is mostly dark, the top part of its head is transparent, and its eyes are clearly visible. According to evolutionary biologists, it developed such a powerful sense of sight as a result of the harsh environment it lives in.
The fish, which is only a few inches long, lives at great depths just below the line at which sunlight can penetrate the water. The marine biologists also found that it uses its large, flat fins to remain motionless in the water.This means that creatures around it cannot see it clearly. Predators lurking above it cannot spot it either, however it can look upwards to hunt for the small fish and plankton it lives off. When a suitable morsel is identified, the barrelfish attacks out of the darkness and swiftly engulfs its prey.To avoid looking at the sun when it moves into shallower waters, the creature's eyes can rotate to look forward so it can see where it is swimming.
Its amazing eyes glow a bright-green and researchers believe it may have developed a form of light filter which allows it to ignore the sunlight and spot the bioluminescence of small fish and jellyfish - it's favourite food.
Unique: The creature lurks at depths of up to 2,600ft where the sun cannot penetrate and when it spots smaller fish or plankton it attacks from the dark and swiftly engulfs its prey The two holes which look like eyes on the front of the fish are in fact nales, olfactory organs similar to human nostrils.
The barrelfish has a crystal-clear liquid over its eyes, held in place by a tiny membrane.If that was to break, its eyes would become exposed to the sea and the pressure that exists at its natural depths of between 2,000ft and 2,600ft would instantly kill it.
Bruce Robison and Kim Reisenbichler of the Monterey Bay Aquarium Research Institute used videos from the institute's remotely operated vehicles (ROVs) to study the barreleyes off Central California.