If this was a hoax, it was one of the largest in living memory. 
 oh, mira grant - is there nothing you can't do? i know there was a time, after the glut of post-Twilight vampire knock-off books ran their course through the publishing world, that mermaids seemed to be trying to elbow in to become the new trend. and i know that some of these depicted mermaids as really fierce and badass instead of the traditional pretty ladies in shell bikini tops. i didn't read any of those, but i knew they existed, and i liked the idea of these predatory mermaids lurking beneath the waves to feast on unsuspecting sailors. i don't know how well this one stacks up against any of those, but i do know that mira grant's strength has always been with her plausibility. she carries science around in her pockets and distributes it like candy throughout her supernatural horror stories and you can't help but nod along and say "yep - seems logical to me!" maybe it's different if you are yourself a scientist, but at the very least, she seems to have done some research which is more than i can say for a lot of less-credible books that skimp on the details and hope the reader doesn't notice. mira grant shows her work, and it makes for a much richer story. 
 this is just a little novella, but it's the perfect punchy length for this story. 
 like everything else she's done, this uses a framing device to break up the pieces of the story, in this case, a television voice-over that warns of the graphic nature of the material it is about to air, and gives some context around the events recorded. 
 the action is made up of found footage from cameras aboard the atargatis; a cruise ship commissioned by the imagine network, a channel known for its cheesy SF/monster movies and its "hyper-reality programming;" dramatized-but-intended-to-be-believed documentaries about cryptozoological beasties. with this particular program the plan was to go way out into waters so remote as to be effectively uncharted to capture footage of real live mermaids. nondisclosure agreements are signed, skeptical scientists are brought in along with their interns and also some women who will operate as insurance in case they don't actually find any mermaids. we are introduced to all of these characters along with the ship's crew, the cameramen, and the host of the show. another of mira grant's skills is in writing really great characters aEUR| and then killing them all. 
 this is no spoiler; from page one you learn that the boat was found drifting unmanned six weeks later, and that none of the two hundred passengers were ever seen again. the only thing that survived on the atargatis was some very disturbing footage, which makes up the story. 
 does she take some liberties with this; with where cameras were likely to be filming, and when? sure, but she makes up for it with all those science-flavored lollipops. you could say that she blinds you with science, but you won't, because that's corny. 
 not only does she present a range of specializations within the oceanography field: a marine phycologist, a marine biomolecular biologist, a marine chemist, a deep-sea cartographer, a cetologist, and an ichthyologist, she lets each of them drive a portion of the narrative as they take readings and analyze their findings. grant also goes into the realities of the responsibilities of captaining a ship, corralling a crew, and the subtle manipulations a ratings-seeking reality show employs to steer conversations and stage a scene. 
 grant's stories teem with authority, you trust her characters. that is a rare treat in this genre, and it is what makes her a writer whose books i look forward to more then my own birthday. 
 no, YOU monster!