Print article Fishermen must wear masks while they are underway, even while sleeping, and the Coast Guard intends to enforce it. That’s an edict issued as a public health emergency by the Centers for Disease Control and Prevention in a Marine Safety Bulletin issued on Feb. 1. It requires the wearing of masks at all times in U.S. waters on all commercial vessels “when boarding, disembarking, and for the duration of travel” to prevent the spread of the COVID-19 virus. The action states that “conveyance operators traveling into or within the U.S. may transport only persons wearing masks and must use best efforts to ensure that masks are worn.”