What Was This Guy Doing in Great Egg Harbor Bay

I was walking over the Route 52 Causeway - the bridge between Somers Point and Ocean City - last night and saw this man in the water. What was he doing?

I assumed he wasn't in danger, since he wasn't displaying the international symbol for someone in the water needing help: arms flaying over head, screaming and splashing loudly.

He was in shallow water in the bay, with what looked like a small inflatable something. Every few seconds he seemed to go under the water for a few seconds, pick something up and put it in the inflatable.

I assume it was some sort of clamming or mussel-collection? Any idea?

I just have to know! Thanks!