The Great Lakes Ballast Water Working Group says that 100 percent of ships bound for the Great Lakes via the St. Lawrence Seaway from outside the 200-mile coastal zone last year received a ballast tank exam.

The working group has just released its 2012 Summary of Great Lakes Seaway Ballast Water Management report.

A total of 6,974 ballast tanks were assessed during 386 vessel transits. Vessels that did not exchange their ballast water or flush their ballast tanks were required to either retain the ballast water and residuals on board, treat the ballast water in an environmentally sound and approved manner, or return to sea to conduct a ballast water exchange.

This is the fourth consecutive year that agencies that comprise the BWWG ensured the examination of 100 percent of ballast tanks entering the Great Lakes via the St. Lawrence Seaway.

Ballast tank exchange is being emphasized in light of the rise in potentially destructive invasive species that have arrived in the St. Lawrence River and Great Lakes, in part due to ships’ ballast water from overseas ports being released into the North American waterways.

The group’s mandate is to develop, enhance, and coordinate binational compliance and enforcement efforts to reduce the introduction of aquatic invasive species via ballast water and residuals. The mission of the BWWG is to harmonize ballast water management efforts among the U.S. Coast Guard, Transport Canada, the Saint Lawrence Seaway Development Corporation, and the St. Lawrence Seaway Management Corporation.

The BWWG anticipates continued high ship compliance rates for the 2013 navigation season.