Well. That is certainly a book.
It basically reads like Mira Grant thought: you know what’s kind of creepy but doesn’t really have that many books written about them? Mermaids. And just went with it. It works though. Creepy as heck at times and once things start happening around halfway through the book, they really don’t stop. The ending is a bit weak and leaves me wanting more answers, but not enough to ruin the entire book.