Sharks Light Up in Neon Colors
Jan. 8, 2014—Researchers studying biofluorescent coral also discovered a shark that reflects certain light, along with a stingray, eel, and other fish. The study, published January 8, used special lighting and camera filters to identify more than 180 species of marine fishes that exhibit biofluorescence.
Transcript
DAVID GRUBER, Associate Professor of Biology, Baruch College - CUNY, National Geographic/Waitt Grantee:
The first fish that we found to be biofluorescent was as a small eel and it was in nighttime. We're diving off of the Bloody Bay Wall in Little Cayman Island. And one of the images, as we're shooting this fluorescent coral, had this eel in it. And we looked at this for a long time trying to figure out, you know, if there was a problem with the camera. And we realized that this fish was indeed fluorescent.
In the process of find it, we started to find, "Wait a minute, here's another fish that's fluorescent, here's another fish. Here's a stingray and that was also fluorescent." So, this just sent us off being like, "Wait a second, this isn't exactly a rare occurrence!"
Then we went to the Solomon Islands in the summer of 2012 and that's where we found the core of our fluorescent fish. This is one of the places with the "coral triangle" which has some of the most abundant marine diversity on the planet.
We started to see that this is something that extends beyond the bony fish and into the cartilaginous fish. Into the rays, maybe it will also be in sharks. So we started to go down, while were in the Solomon Islands, we were trying to get the sharks close enough that we could film them.
And we also went to a series of aquariums and it turns out that some of the smaller sharks-the cat sharks-are brilliantly fluorescent. As bright as some of the brightest fish, as bright as the corals.
When you see the images, when you see it's all over. It's in their eyes, it's on their skin. Um, this is making me think that it is something that's important physiologically for this animal. And we...at this moment we do not know what the function is.
So in order to see the phenomenon of biofluoresence, we use scientific filters and we created this same pure blue, a very tight-notch blue filter. And then that is the light that's always bathing these animals. They live in a blue world. The world is blue all the time. And we did this. We re-created the blue light. But then when we film it, we don't want to see blue light. We just want to see light that is getting absorbed by these animals and is coming back off. So we have a yellow filter that we put in front of our camera lens and that only allows us to see the fluorescence-the reds, the greens-that are coming off the animal.
So what's next? Can the fish see this? Is this playing a role in their behavior? I'm really interested at the protein level. We identified over a 180 species in the single paper that has opened up more questions that we're really excited to start digging into.
I just find the real serenity and beauty to being in the reef at night. And now when we add on this kind of fluorescent layer, it's like being on another planet. You know, you're on some surreal Martian landscape.