HALIFAX—A second round of COVID-19 testing was scheduled Thursday for the crew of two Canadian Coast Guard vessels that are under lockdown in Dartmouth, N.S. The coast guard said all 44 crew members of CCGS Jean Goodwill and CCGS Hudson were initially tested Dec. 24 and were negative, after they were exposed to a contractor who had worked on the ships and who had tested positive for COVID-19. A second test is optional for the crew, the coast guard said, adding that all of the members were isolating aboard the vessels or at home. The crew was asked to isolate away from family and friends until Jan. 6. “When coast guard was advised of the exposure [one contractor employee] on Dec. 23, public health originally advised that crew members were to self-monitor for any symptoms,” the coast guard said in a statement Wednesday. “On Dec. 24, all employees from both …