Abridged Moby Dick as good as full?

I recently borrowed a book from my grandfather, an old copy of Moby Dick. I got halfway through before realizing that it is an abridged version. It has 99 Chapters instead of 135. Now, I know that at least a few of those are all on some outdated science of whales which has nothing to do with the main plot, but am I missing anything vital? I will be reading this again at some point in the next ten years most likely, I would just like to know.