My favorite science book of the year? Tough competition against How to Clone a Mammoth, but technically that was last year…) In any case, I highly recommend Sex in the Sea: Our Intimate Connection with Sex-Changing Fish, Romantic Lobsters, Kinky Squid, and Other Salty Erotica of the Deep, although I would not recommend reading it on a plane, as I did, which can cause some embarrassment when your seat mate politely inquires what the obviously hilarious book is that you are reading.
Some of my favorite creatures in the book: female fish who prefer clean nests (over large ones), male fish passing as females for a chance to get to the females despite their larger counterparts, female lobsters molting right before sex (but needing their new exoskeletons to firm up just enough to actually survive the act), penis fights that are really insemination attempts (you will have to read it to believe it), copulating conga lines, and more. The author is as deft a science writer as Mary Roach and can easily use all the funny stories to segue into lessons for fishery regulations. A wonderful book beyond the pure entertainment value.