I don't know if mermaids exist today on earth but maybe in other probable reality. See below.

"I told you that you presently perceive only the surface of the moment; so you also perceive but one line of the species' development. Yet even within your system, there are hints of the other probable realities that also coexist. The dolphins are a case in point. In your line of probability they are oddities, yet even now you recognize their great brain capacity, and to some dim extent glimpse the range of their own communication."

"At one time on your earth, in the way you look at time, there were many such species: water dwellers, with brain capacities as good and better than your own. Your legends of mermaids, for example, though highly romanticized, do indeed hint of one such species' development. There were several species small than the dolphins, but generally the same structurally. Their intelligence was indisputable, and old myths of sea gods arose from such species. There is even now an extremely rich emotional life on the part of the dolphins, to which you are relatively blind; and more than this, on their part a greater recognition of other spcies than you yourselves have."

Source: The Unknown Reality, Volume One (A Seth Book)

The video is very well-done, lovely, and entertaining, but it is a fake..."docu-tainment", if you will. I would love to believe it, but if you watch the end credits it explains that its fiction. If you do some "googling", you can also find information on the actors and actress that played the scientists.

The whole "bloop" thing is real, though, and intriguing--although if you look it up, you'll see that if it does come from a living creature in the recesses of the deep, it would have to be much larger than any merman or mermaid:

http://en.wikipedia.org/wiki/Bloop