A Transparent Noggin

So recently the people at the Monterey Bay Aquarium think they have solved the mystery of a very peculiar fish. This fish is commonly called the barreleye (Macropinna microstoma) and has some peculiar adaptations for life in the deep. The fish was first described in 1939. It has, since that time, been assumed that it's tubular eyes were very adept at collecting light. What they didn't know was that the eyes moved. It was believed that the fish had "tunnel vision" and could only see a set area right above its head.


The two spots above the mouth are actually the fish's nostrils. It was thought that the eyes enclosed in its transparent dome could only look upward. Recently, however, researchers with Monterey Bay used ROVs (remotely operated vehicles) to film these creatures in the wild. In the video you can see the eyes rotate quite a bit. It also appears that these fish steal their food from siphonophores floating by with food trapped in their tentacles. Siphonophores, by the way are Cnidarians (pronounced nye-DAIR-ians) and are related to corals and jellyfish. These creatures trap animals in very long tentacles and consume them similar to jellies. The barreleye sees the trapped food and then swwops in for the steal.

The "sheild" around the eyes is also a new discovery. Up until this video, any specimens found had no sheild. This was probably due to damage on the way up from the deep . This is evident in the following illustration from the Canadian Museum of Nature.

As you can see, it looks a bit different from the same fish studied alive using the ROVs.
They also discovered how the fish swims. Using its amazing flat fins, they can almost hover in place. They can also manuever quite well. To find out more, read the press release here.