SUPERIOR, Wisconsin — A new study of ballast water in Canadian and American lake boats has confirmed that it can carry invasive hitchhikers from other parts of the world into Lake Superior.
Results of the research were released recently by the University of Wisconsin-Superior's Lake Superior Research Institute (LSRI).
The study documented six species of non-indigenous zooplankton not yet established in western Lake Superior.
One of them, Hemimysis anomala—also known as bloody red shrimp—had never been detected previously in any of the Great Lakes.
Researchers found the foreign species in samples of ballast taken between late summer and early winter of 2017 from 10 different lakers operated by U.S. and Canadian shipping companies.
Each boat had taken on ballast water at ports in the four lower lakes before voyaging to the port of Duluth-Superior where the samples were collected.
"We are grateful to the U.S. and Canadian laker industry for facilitating this study," said LSRI senior scientist Allegra Cangelosi.
Cangelosi told Tbnewswatch "it is likely" the organisms were originally brought to the Great Lakes by ocean-going ships.
She said the chances that any of the organisms could establish themselves and harm Lake Superior are unknown, and may be negligible, but the results point to the need for more research, including "on developing reliable and cost-effective approaches to monitoring harbors and ship ballast water for specific new unwanted non-indigenous species."
A spokesperson for the Lake Carriers Association said that since 1993, with the discovery of the Eurasian ruffe in western Lake Superior, and the discovery of viral hemorrhagic septicemia in Lake St. Clair in 2003, U.S. shippers have adopted voluntary management practices and worked with their Canadian counterparts to help stop the spread of non-indigenous aquatic species.
The Eurasian ruffe, a member of the perch family, has been found in the Kam River in Thunder Bay and on the U.S. side of Lakes Superior, Huron and Michigan. The Ontario Ministry of Natural Resources and Forestry says it has the potential to cause serious damage to native fish populations because it can quickly become dominant.
The ministry says VHS, an infectious disease, was first detected in Lake Ontario in 2005.
Bruce Burrows, president of the Canada-U.S. Chamber of Marine Commerce, said his group supported the LSRI project and will continue to work with government and scientists to find "practical options" to manage ballast water.
According to Burrows, "Canadian shipowners have invested $1.5 million in a ballast water research and technology fund to expand research and find technical solutions that are operationally and economically feasible for Canadian domestic fleets.
The University of Wisconsin project isn't the first to focus on the issue of ships moving invasive species from one part of the Great Lakes to another.
The International Joint Commission reports that a Canadian Department of Fisheries and Oceans study conducted between 2007 and 2009 found that the spiny waterflea, a non-native species in Hamilton Harbour that had been in the lakes since at least 1982, was present in ballast water headed for Lake Superior, where it hadn’t been detected previously.
The spiny waterflea poses a threat to native zooplankton which are an important food for native fish species.
It has now spread to more than 100 inland lakes in Ontario and into the Winnipeg River system.
— tbnewswatch.com