Any piece of bare aluminum or steel should be corrosion proofed in some way if it is to be in a marine environment.
If the hub was an off the shelf part from a major manufacturer it may have been coated or clear anodized. If it was custom made and just polished, then it should be taken to a plating shop. Any bare aluminum in Jersey salt water will corrode fast. Talk to a plater they can tell you what your options are.