Isle Royale National Park continues to combat invasive species

Courtesy: Isle Royale National Park

HOUGHTON — The National Park Service (NPS) continues its efforts to prevent the spread of aquatic invasive species. Invasive species such as the zebra mussel have caused extensive damage to natural resources and cost millions of dollars in eradication and control efforts. Ballast water discharges from ships (water used for ship stability) is a primary pathway for introduction of invasive species.

NPS and its partners have conducted significant research into ballast water treatment technology, most recently this summer at Isle Royale National Park. Results are in from the summer testing of two freshwater ballast treatment systems on the NPS ship, Ranger III. NPS tested a manually operated rapid response treatment process that used chlorine and a neutralizer and a fully automated permanent treatment system using filtration and ultraviolet (UV) technology.

The shipboard status tests were conducted in September of 2014 and the final report was recently released. Both systems passed United States federal and international standards for two out of three requirements: discharge of living zooplankton and indicator bacteria. The systems did not meet the standards for phytoplankton, which remain some of the toughest organisms to kill. Since the numbers of live phytoplankton collected exceeded the standard, the test facility conducted a viability analysis.

After giving the organisms optimum conditions for growth and reproduction it was determined they were not viable (not capable of reproduction) after undergoing either of the treatments. More information on results and criteria will be posted on the Isle Royale website, www.nps.gov/isro.Isle Royale National Park Superintendent Phyllis Green commented: “We are pleased with the performance of the UV system and hope that this system and others will soon pass type. Prior to installation of the UV treatment system, Ranger III used a rapid response treatment process developed and refined with US Geological Survey and industry partners, the American Steamship Company and The Glosten Associates. Green continued, “We have developed equipment to enable the rapid response process to be implemented on larger ships and are fortunate the process and equipment will be tested in California in December.

We are hoping to develop and work with partners to set up a pilot demonstration of rapid response and risk reduction in the Great Lakes in the future.”NPS pioneered emergency treatment of ballast water in 1994 during a grounding incident at Key Biscayne National Park in Florida and on Ranger III in 2007 to reduce Isle Royale National Park’s exposure to a new fish disease, viral hemorrhagic septicemia. Both instances used manual methods to treat the ships. With Great Lakes Restoration Initiative funding, the NPS was able to select and install a fully automated filtration/UV based system for permanent ballast treatment. Testing of both systems occurred in September of 2014 under the direction of Dr. David Wright, Emeritus Professor of Environmental Toxicology at the University of Maryland Center for Environmental Science and Chief Scientist at Environmental Research Services based in Baltimore, MD.

The UV system (Hyde Guardian Model HG60® Ballast Water Management System) relies on a combination of disc filtration and UV disinfection. The rapid response system can use any liquid biocide and neutralizer and current tests have been run using bleach with ascorbic acid (vitamin C) to neutralize. In 2008, NPS, the US Geological Survey and The Glosten Associates began development of rapid response methods to treat a ship using common equipment. Trials were performed on the Great Lakes bulk carrier Indiana Harbor and the resulting recommendations are provided in Isle Royale’s Emergency Ballast Treatment Salvor’s Guide. NPS also helped coordinate the design of a skid-mounted ballast treatment system to expand the potential to treat high risk ships.