"Melville devotes entire chapters (although all his chapters are brief) to various asides on whaling, whale biology, history, and seafaring."
You definitely must have an abridged version. As someone who's read the unabridged version, Melville is nothing close to brief. Usually, I have an aversion to abridged books; I feel like I'm "missing out". In this case, the abridged version is much better for today's reader. The discovery channel wasn't broadcast in HD at the time, so these painfully long chapters on whale species would have been much more interesting. :)