It's only been over the past four years that researchers have begun studying whether ship hulls bring in invasive species.

When it comes to ballast water, scientists and environmental officials know it's a known carrier. It's considered the No. 1 way invasive species move worldwide.

“Foreign vessels are required to do ballast water exchange in deepwater,” said Lt. Eric Allen, a U.S. Coast Guard marine inspector and investigator, who covers Coos Bay.

Oregon law also requires some vessels to exchange ballast water when moving along the coast from distances greater than 200 miles. The law potentially would pertain to ships destined for recycling. The Oregon Department of Environmental Quality is the lead enforcement agency, but has never been funded for such work, according to a 2005 report by the Pacific States Marine Fisheries Commission.

Ships take on ballast water once the holds are empty, or as fuel is burned, to bring on weight so they don't bauble on the top of the water. In most cases, Allen said, vessels do a 300-percent ballast exchange, flushing the water three times, usually about 200 miles offshore. The theory is invasive species won't survive. Once in port, to maintain stability as wood chips or other cargo is loaded, the ship discharges the water.

It's Allen's job, in part, to ensure crews do the exchange. Otherwise, they aren't permitted in port. It works on an honor system.

“If there's any doubt whatsoever, we can test it,” he said.

Ships are required to document the longitude and latitude of ballast water exchanges and send reports to the Coast Guard prior to entering a harbor.

Allen estimates he's inspected up to 1,000 deep-draft vessels and never pursued a civil penalty against a company for failing to exchange ballast water.

The show stoppers are usually fire and safety issues, he said. When it comes to ballast exchange, Allen believes captains are careful. While it can be tricky to exchange ballast water at sea, a delay in port over a dispute costs money.

“I haven't come across anything here in Coos Bay that would lead me to believe they are gun-decking it or skipping it,” Allen said.

- City Editor Elise Hamner