The Associated Press

HOUGHTON, Michigan — Technicians have used a vessel that hauls passengers to Isle Royale National Park for testing a refined treatment method to rid ships’ ballast water of invasive species.

Isle Royale Superintendent Phyllis Green says a marine engineering firm used the M/V Ranger III last weekend to try out prototype equipment for mixing chemicals that can kill organisms in ballast tanks. The equipment shortens the time needed to treat a ship.–Ranger-Ballast-Test