To some extent the actual weapons system used would be irrelevant. If the US declared a blockade, all commercial shipping insurers would immediately withdraw coverage in that zone. Conflict zones are (mostly) uninsurable, and large merchant ships don't sail without insurance. And the US would immediately back that up with wide-ranging economic sanctions prohibiting any entities involved in trade with China from being able to use any part of the US financial system. Thus almost no neutral flagged ships would be able to call on Chinese ports.

The US Air Force has put a renewed emphasis on air-delivered naval mines. During WW2 those weapons played a major role in starving Japan and they're just as effective today.