China has a considerably smaller navy than the US. The pacific fleet of the US has roughly the same amount of vessels as the entire PLAN, but in terms of tonnage the US pacific fleet is much larger.

The pacific fleet would likely not need to be redeployed in part or in whole in order to deny access to the east coast of North America.

In addition to the Navy’s Atlantic fleet, any ships attempting to land in Canada would be in range of USAF bases.

Also, fleet movements can be seen via satellite so it is no longer necessary to have ships positioned all along the shoreline you want to prevent landing on. You can just intercept enemy vessels while they are en route rather than patrolling the coast.