Cargo ships take on ballast water for stability when they’re not carrying cargo. On cargo vessels water ballast is added to the ballast tanks when empty to increase propeller immersion, to improve steering, and to control trim and draft.  Ships discharge ballast when they load freight, expelling tons of water and anything else—from pathogenic microbes to mollusks and fish—that’s in it.  Carried in this water are plants, animals, bacteria, and pathogens. These organisms range in size from microscopic to large plants and free-swimming fish. These organisms have the potential to become aquatic nuisance species (ANS). ANS may displace native species, degrade native habitats, spread disease, and disrupt human social and economic activities that depend on water resources.  

Many Kentucians travel north to enjoy fishing and boating on the Great Lakes during our hot summer months.  At least 185 non-native aquatic species have been identified in the Great Lakes, and ballast water is blamed for the introduction of most ANA.  Among the most notorious invaders are the zebra and quagga mussels and gobies.   The zebra mussel actually is a recent addition in a long history of invaders, ranging from rainbow smelt, alewife, and lamprey to the recently introduced ruffe and spiny water flea.  Any ship carrying ballast water is a potential source of an ANS.

In recent years there has been increased international focus on Ballast Water Management (BWM) due to the ecological, economic, and potential health threats caused by the spread of ANS from ballast water. The United States Coast Guard is responding to these concerns through a comprehensive national BWM program. This program applies to all vessels equipped with ballast water tanks that operate in U.S. waters and are bound for ports or places in the U.S. 

Highlights of the program are:  (1) requires mandatory ballast water management practices for all vessels that operate in U.S. waters; (2) establishes additional practices for vessels entering U.S. waters after operating beyond the EEZ; and (3) requires the reporting and recordkeeping of ballasting operations by all vessels.  More information on the BWM program regulations may be found in 33 CFR Part 151 Subparts C and D.  Subpart C sets forth the federal rules for BWM for ships traveling in the Great Lakes and Hudson River region and Subpart D applies to the waters of the United States.