translation of the lower note:
NOTE: From 10:00 p.m. the Port is closed to navigation for vessels less than 15 meters in length and
suspension of all types of recreational aquatic activity throughout the jurisdiction of the island of Cozumel, so all precautions and safety measures relevant to navigation must be taken by the entire maritime community.
So yes, like most closures it covers ALL activities on BOTH sides of the island. This is a small boat closure to craft less than 15M (49Ft). Enforcement is another issue but the port captain can fine the hell out of an operator if they violate the closure, again it is Mexico so enforcement may be spotty.