Presidential Executive Order 13998 addresses COVID-19 prevention guidelines for travelers.
Per Section 3:  
The Secretary of Transportation (including through the Administrator of the FAA) and the Secretary of Homeland Security (including through the Administrator of the TSA and the Commandant of the Coast Guard), in consultation with the Director of CDC, shall promptly provide to the COVID-19 Response Coordinator recommendations concerning how their respective agencies may impose additional public health measures for domestic travel.

I have confirmed with CBP that at this time they have ’not received specific information on changes to procedures’.
Per the EO Section 5(d):
Sea Travel. The Secretary of Homeland Security, through the Commandant of the Coast Guard and in consultation with the Secretary of HHS and the Director of CDC, shall, within 14 days of the date of this order, submit to the President a plan to implement appropriate public health measures at sea ports. The plan should implement CDC guidelines, consistent with applicable law, and take into account operational considerations.

The EO was signed January 21, 2021.  Therefore, the plan is due February 4, 2021.
Updates will be provided upon receipt.