Apparently the National Oceanic and Atmospheric Administration (NOAA) published a newsfeed article titled Conclusive Evidence of the Existence of Aquatic Humanoids. According to claims made in this article from a Kenyan news source, mermaids can be seen on paleolithic cave paintings and actually still exist in the ocean.
I don’t know if I’m fully convinced of the cliche image of a magical, seductive girl rooming the ocean half-naked. But the deepest parts of the ocean are more unknown then outer-space at this point. I do think there could be some ‘Aquatic Humanoid’ creature down there. Maybe mermaids are real.