ALBANY -- A state judge has upheld rules to require commercial ships in New York waterways to retrofit with ballast water treatment systems by 2012 and to require such systems in new ships starting in 2013 as a means of killing invasive species.

The state Department of Environmental Conservation rules, which also prohibit bilge discharges, are meant to keep additional foreign aquatic plants and animals from the St. Lawrence River, Great Lakes and other New York waterways.

Like California's regulations, they add ship overhauls to the new federal requirement for offshore ballast exchanges by inbound commercial ships at least 79 feet long.

Justice Robert Sackett rejected New York, Albany, Oswego and Great Lakes ports' concerns of economic harm.