Portland is so close to the ocean. So, where should a person buy fish and shellfish?
The old standby is Newman's in City Market (735 NW 21st, 227-2700). An eastside option is Pacific Seafoods (3380 SE Powell, 231-6054).
There is no substitution for smelling, observing, and asking questions. And while we might be close to the ocean, the fish and shellfish aren't necessarily cheap. But do you want cheap fish or shellfish (honestly, the answer should be no).