How bottom-dwelling fish conceal themselves from predators
However, little is known surrounding the fish who live close to the ocean floor and how they are able to utilize these abilities.
By JERUSALEM POST STAFFSelene vomer(photo credit: WIKIMEDIA)
To conceal themselves from predators, many fish employ light-catching camouflage abilities known as reflective crypsis through various methods such as transparency, reflection and counterillumination to keep themselves hidden even at the deepest depths of the ocean.However, little is known surrounding the fish who live close to the ocean floor and how they are able to utilize these abilities.Considering light refraction is a major component in underwater camouflage strategies, with little to no sunlight present at the bottom of the ocean, how they pull off this feat has been a mystery of its own.According to a team of scientists led by Smithsonian's National Museum of Natural History research zoologist Karen Osborn and Duke University biologist Sönke Johnsen, who published their finding in the journal Current Biology, some of these fish absorb light so efficiently that even in bright light they appear as silhouettes with little to no discernible features - even when surrounded by bioluminescent light, the fish appear invisible.In some of these bottom-dwelling fish, the arrangement of pigment-packed granules found on their skin absorb nearly all the light it comes into contact with, reflecting as little as .05% of light back - giving the fish the dark appearance."Many of the black fish found in the deep sea absorbed more than 99.5% percent of the light that hit their surfaces," the Smithsonian said in a press release. "That means they are ultra-black--blacker than black paper, blacker than electrical tape, blacker than a brand-new tire. And in the deep, dark sea, where a single photon of light is enough to attract attention, that intense blackness can improve a fish's odds of survival."Osborn first encountered this phenomenon while trying to photograph some of these fish, when she noticed she could not capture detailed images of the no matter the angle of the camera."It didn't matter how you set up the camera or lighting--they just sucked up all the light," Osborn said."Effectively what they've done is make a super-efficient, super-thin light trap," Osborn said. "Light doesn't bounce back; light doesn't go through. It just goes into this layer, and it's gone.""These pigment-containing structures are packed into the skin cells like a tiny gumball machine, where all of the gumballs are of just the right size and shape to trap light within the machine," said Alexander Davis, a co-author of the study and doctoral student in biology at Duke University.
