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The biggest fear most surfers and swimmers face when they head out deep into the oceans, is being attacked by a shark. Now, a new study released by Australian scientists has revealed that these fish may be color blind - A breakthrough that may not only help make the waters safer, but also, prevent these mighty animals from accidentally getting entangled inside fishing nets.
Using a technique called microspectrophotometry, scientists examined the retinal cells of seventeen species of sharks, caught off the shores of New Zealand and Australia. What they discovered was interesting. The retina of a normal living creature comprises of two kinds of light receiving cells - Rod cells, which are extremely light sensitive and help measure brightness, allowing for normal eyesight day and night and, Cone cells which help distinguish between colors.
While the scientists were able to find plenty of Rod cells in the retinas of the sharks, ten of the seventeen species had no Cone cells. The other seven did have some, but only of a single type, sensitive to color wavelenghts of about 530 nanometers, which happens to be the wavelength of the color green. This means that while the fish are able to distinguish between shades of grey and in some cases even blue/green, they cannot see any other colors.
These findings are consistent with similar research done on other aquatic animals like whales, dolphins and seals that all possessed only the green Cone cells. Scientists believe that distinguishing between colors is not that important to the sea creatures, because colors are quite useless at the depths at which they live. Instead, they seek out their prey or predator, based on how much it contrasts or stands out, compared to the surrounding waters.
Since there are over 400 different species of sharks, more studies need to be done to see if the color blindness extends to all of them. But, scientists are very excited with this breakthrough. They believe if it does holds true for all sharks, fishing lures and swimming attire can be designed in colors that are less prominent to sharks, making the waters safe for both man and fish! Now, if we could only find a way to make their hearing less acute!
Resources: news.nationalgeographic.com, news.discovery.com,