The Great Waters Research Collaborative (GWRC), a project of the University of Wisconsin-Superior's Lake Superior Research Institute (LSRI), released results of a study on nonindigenous species of plankton in ballast discharges from US and Canadian Lakers (a term used to describe vessels designed and operated on the Great Lakes) to western Lake Superior.
The research builds on work conducted by others in the Great Lakes in recent years.
Operators of the Lakers proposed the study as a means of complying with Minnesota Pollution Control Agency ballast water permitting requirements and approached GWRC to undertake the scientific research.
The US Environmental Protection Agency paid for the study via the US Maritime Administration portion of the Great Lakes Restoration Initiative.
The study documented five species of non-indigenous zooplankton not yet established in western Lake Superior, including Hemimysis anomala (bloody red shrimp), in Laker ballast water discharged there. It also detected, in uptake water, a species of zooplankton (Paraleptastacus wilsoni) that had not previously been recorded in the Great Lakes.
Some of the species, including this one, live in harbour sediment and may have escaped routine surveillance to date.
Ten US and Canada-flag Lakers participated in the study and sampling took place in 2017, primarily in the late summer through early winter, and focused on ballast water discharges into western Lake Superior of water loaded from the lower four Great Lakes.
GWRC also conducted voyage-wide sampling on a subset of voyages, documenting selected characteristics of the source water system and the associated ballast water uptake, plus ballast water discharge and the associated receiving system in western Lake Superior.
Ballast water samples were microscopically analysed for nonindigenous species of aquatic organisms. Special emphasis was placed on detections of Hemimysis anomala which, until the summer of 2017 when a single specimen was found, had not previously been detected in western Lake Superior.
A genetic detection probe targeted to Hemimysis anomala was used to analyse source and receiving water for presence/absence of its environmental DNA.
“We are grateful to the US and Canadian Laker industry for facilitating this study. Their willingness to support this research demonstrates their strong commitment to the health of the Great Lakes,” said LSRI senior scientist Allegra Cangelosi and principal investigator of the study.
“The chances that any of the organisms we detected in this study could survive, establish and harm Lake Superior are unknown, and may be negligible. The results nonetheless support greater research emphasis on identifying and validating performance of new ballast water management alternatives for Lakers, as well as better understanding the risks of ballast-mediated transfers of organisms within the Great Lakes.”
“Since 1993, with the discovery of the Eurasian ruffe in western Lake Superior and continuing with the discovery of viral hemorrhagic septicemia in Lake St Clair in 2003, the US-flag fleet has actively engaged in voluntary management practices that have helped stop or slow the spread of nonindigenous aquatic species throughout the lakes,” said US-based Lake Carriers’ Association’s representative Thomas Rayburn.
“The Chamber of Marine Commerce and its members are pleased to have supported this important research and we continue to work with government and scientists to find practical options to manage ballast water,” said the Chamber of Marine Commerce president Bruce Burrows.
“Canadian shipowners have invested CA$1.5M in a ballast water research and technology fund to expand research and find technical solutions that are both operationally and economically feasible for the Canadian domestic fleets that operate within the unique conditions of the Great Lakes and St Lawrence region.”
“This study is an important benchmark in protecting Lake Superior and inland waters from unwanted, aquatic species that are not native to the Great Lakes,” said Minnesota Pollution Control Agency Commissioner John Linc Stine.
“We’re grateful for the important work done by the Lake Carriers’ Association and Chamber of Marine Commerce members. Now it’s time to get to work with the vessel owners to develop additional ballast management strategies that further protect Minnesota waters.”
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