Bright side is that shellfish aquaculture is 100% non-polluting, unlike fish aquaculture.

Shellfish perform an important function cleaning up pollution - but those aren't the ones you want to eat. Shore-based shellfish aquaculture is always going to be at the mercy of runoff from the land, excepting places that have virtually no runoff (dry islands like Cuelebra, Bonaire, of Lanai) - and there's plenty of open ocean (NZ green lips are raised relatively far from shore)

BTW/FWIW, NZ exports green lips, already shucked and frozen. If you're in the US, I found them at Trader Joe's. But local food is better.

Gotta wonder how they'd do off the New England coast. The local fishery is contracting. This'd be a way to keep those guys out on the water. I have no idea where to find seed stock, but I'll bring it up (we buy fish from a fisherman's' co-op based in Gloucester).