On Friday I was one of the only people out in the Sound around 4:00 because of the light wind (me on my foil + 7m) and I ran in to a pod of Dolphin about 400m South of the river. Looking it up they were probably Harbour Porpoises.
Saw 4 of them crest about 50m in front of me. I immediately looked around for Orca fins but thankfully didn't see any, I was a bit scared though.
They stayed around for about 20 minutes but I couldn't see them again, the Dolphins we have in these parts are quite shy. I could hear their whistles not far from me as they came up for air though.