WASHINGTON, March 10 (UPI) -- The U.S. government says it will develop tighter regulations governing the discharge of ship ballast water, a major source of troublesome invasive species.

The Environmental Protection Agency has agreed to rewrite a permit system challenged by a coalition of environmental groups in a legal battle, the Los Angeles Times reported Tuesday.


Ballast water is used by large commercial ships to maintain stability on long voyages and is taken on and discharged in coastal ports, often releasing unwanted invasive marine species in the process.

"Whole ecosystems are transported from one part of the world to another," said Thom Cmar, an attorney with the Natural Resources Defense Council, one of the groups involved in the case.

Under a settlement filed in the D.C. Circuit Court of Appeals, the EPA will devise limits for discharges of organisms such as plankton and microbes and will put them in place in 2014.

The lag time is designed to give the maritime shipping industry time to create systems to treat ballast water before it is released overboard.

"This settlement represents the first time in 35 years that EPA has agreed to control discharges of ballast water from ships in the same way that other industries are controlled when they discharge pollution to the nation's waters," said Nina Bell, executive director of Northwest Environmental Advocates.