Ship strike mortality remains one of the two primary causes for lack of recovery of the North Atlantic population of northern right whales (Eubalaena glacialis). As a result, NOAA Fisheries has identified a number of actions to reduce interactions between ships and whales. Central to this approach is the concept that ship strike mortality risk can be reduced either by slowing ships or by separating vessels and whales. More specifically, in the Great South Channel Seasonal Management Area (GSCSMA) of the southern Gulf of Maine, NOAA is considering an April July requirement that all vessels over 300 gross tons travel no faster than 10 kts. To physically separate whales and vessels, NOAA is also considering (a) designating the Great South Channel critical habitat (GSCCH) area as an International Maritime Organization (IMO)-approved Area To Be Avoided (ATBA) and (b) narrowing (by 1 nm) the Boston Traffic Separation Scheme (TSS). We analyzed the risk reduction of right whale ship strikes which could result from the above two proposals by using data on commercial shipping traffic and right whale sightings collected during AprilJuly 1999-2005.