Featured Image Credit: MBARI via Youtube
By Eva Gruber
Chimaeras are the long-lost relatives of sharks and rays, and along with them, belong in the family of cartilaginous fishes. Although they split off over 400 million years ago, chimaeras share many features in common with sharks and rays including a cartilaginous skeleton, and leathery egg cases. Today, they are mostly confined to the waters of the deep sea, and are much lower in diversity than they were millions of years ago.
Even though lacking in diversity, very little is known about the species that exists today, due in large part to their mostly deep-sea existence. They are also called ratfishes because of the length and skinniness of their caudal fin, or ghostfish because of their pallid coloration and eerie habitat.
This past week, the Monterey Bay Aquarium Research Institute (which is often on the cutting edge of deep sea science) released new video showing one species of ghostfish that has been caught on film for the very first time.
With the advent of video technology, we are able to retrieve video and images of natural behaviors of the species in their natural habitat – especially important for creatures of the deep. Where before, we were limited only to the knowledge gained from seeing what we could trawl and bring up, which was an indelicate procedure and all too often resulted in destroyed and dead specimens.
This particular video is from a 2009 geological expedition to the deep-sea habitats off the coast of California and Hawaii. Even though the scientists leading the expedition weren’t looking for animals, they kept the film rolling when they came across any. One particular chimaera that the ROV kept coming across looked like a new species, since it looked so differently from other chimeras in the region.
Although no one from MBARI could identify it, they enlisted the help and expertise of ichthyologists across the globe. Chimaera experts including Ebert identified it as a point-nosed blue chimaera (Hydrolagus trolli) which is usually found in deep waters off the coast of Australia and New Zealand. This new video of a previously-known species (but one that had never been observed alive) is incredibly valuable as it provides scientists with a glimpse into how the animal moves, how it orients itself, and other priceless insights from a depth where no person can dive.
In the end, its not at all surprising that the pointy-nosed blue chimaera would live across vast expanses of entire oceans – after all, at least three other species of chimaera do just that. And it is suspected that the ranges for many deep-sea species are larger than the snapshot glimpses scientists get from trawling surveys or a lucky camera shot. All that remains now is for more scientists to go out there and get the data.