I am assuming it is possible to calculate the mass of water if the volume is known. My assumption is that doing this for stagnant water, in a container perhaps, is easy.

However I want calculate, approximately, for a wave of water at sea.

What kind of information would I need if I wanted to calculate the mass or volume of a wave of water?

For example, if I know the space from one wave crest to the next and the period could I use that information?

So again how would I calculate the mass of a wave of water?