I thought this was a Sooty Shearwater at the time I took the photo, and I didn't think we got this close to an Ashy Storm-Petrel, which is why I'm wondering if I'm ID'ing this correctly.
That's a nice photo of an Ashy Storm-petrel. Sooty Shearwaters are MUCH larger birds, don't have a notched tail, hold their bills parallel to the water, etc.