As research scientist for the Marsden funded project on diversity of deep-sea fishes of New Zealand, I have to analyse hundreds of hours of video footage taken during our surveys. Sometimes, amazing creatures appear on the screen, often when you least suspect it. Here is a shot that really surprised me. I virtually stepped back about a meter from my screen when a large sand tiger shark (Odontaspis ferox Risso, 1810) first swam towards me.
This is a large female, close to 400 cm in length. The species is a rare one, although it has been reported from scattered localities around the world. The sensors attached to our video system recorded a depth of 880 m, exactly the same depth as the deepest known record for the species. However, this species is sometimes spotted at scuba diving depths.
You will have noticed that we are using blue light to illuminate our footage. Indeed, at 880 m depth, there is no natural light or rather I should say no light that can be seen by a human eye. There is still a little bit of light that some deep sea organisms can use to find their prey. We are using blue LED systems because it appears that most fish species that we are interested in cannot see this kind of light. Because our light source is invisible to fishes, they are not disturbed and behave naturally in front of the camera, making our observations more accurate.
More amazing species from the deep to come later! Right now, I have started to process videos from recent fieldwork around Great Barrier Island and Three Kings Islands. In the meantime, you can learn more about our project by visiting the Te Papa Fish Team website.
Te Papa scientists recovering a video unit sent underwater to film deep-sea fish life. Note the bait bag at the front which is used to attract the fish towards the camera and the blue light at the top of the frame.
