From the author:
As I started writing, I only knew one or two things -- that there would be whales involved somewhere, and that the Crabs would be in the tunnels and sewers under the city. After some fascinating research into the history of excavations and tunneling I made a start.
I worked out a full ecological profile and lifecycle for my "beasts" but most of that went by the board as the plot took over. It went quickly, and I found myself enjoying it immensely. It runs in my head like a movie, and I'd love to see it on the big screen one day, or as a comic book. That's how I think of it -- big, brash and bloody.