In order to significantly reduce the risk of ship strikes to the highly endangered North Atlantic Right Whale, ships of 300 gross tons and above should avoid the area between the period of April 1st through July 31st. Reference IMO Sn/Circ.272.  Where the boundary of the Area to Be Avoided (ATBA) is co-linear with the boundary of the Traffic Separation Scheme or the boundary of the Mandatory Ship Reporting Area, it has been offset slightly for clarity.