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Stop the tide of invasive species in the Great Lakes

A ship that discharges ballast water at sea. Credit: Dr. Sarah Bailey, Fisheries and Oceans Canada, Canada

The release of ballast water from marine vessels has brought hundreds of invasive species to coastal ecosystems around the world, causing great disruption to fisheries and biodiversity. Attempts to control the invasion of aquatic organisms have generally been successful. However, new studies have shown that since the mid-2000s, bilateral restrictions on vessels entering the Great Lakes have been very effective in reducing most of the invasive species in the world’s largest freshwater ecosystems. A recent study was by Anthony Ritchardi (Professor of Biology at the Redpath Museum and Beerer Environmental School, McGill University) and co-author Hugh Masizac (Professor and Chairman of the Canadian Research Committee at the Five Great Lakes Environmental Institute, University of Windsor).Was announced in Conservation letter..


“I don’t know of any other documented cases where large water system intrusion rates were suppressed by management intervention,” Ricciardi said. “This protective layer is clearly beneficial. For example, there are many highly invasive freshwater species in Europe. Ballast water And it will almost certainly grow in the Great Lakes. Regulations are likely to prevent their adoption. “

The most invaded freshwater ecosystem in the world

It has never invaded other freshwater ecosystems on Earth as often or as often as the Great Lakes basin. Over the last two centuries, nearly 190 exotic fish, invertebrates, plants, plankton, and microbes have established populations in the basin. Nearly 65% ​​of the recorded intruders since the opening of the St. Lawrence Sea Channel in 1959 were taken to the Great Lakes by ship ballast tanks from overseas ports. These include infamous stowaways such as zebra mussels, quaggga mussels, barbed daphnia pulexis, and round goby. Each of these is one of the most ecologically and economically damaging invaders in the basin.

From 1959 to the mid-2000s, one new intruder was discovered on the Great Lakes every 6-7 months.

This onslaught harmonizes regulations by Canada and the United States, prompting a move to require all vessels to flush salt water through ballast tanks while still in the open sea before entering the St. Lawrence Sea Channel to the Great Lakes. Experiments have shown that saltwater flushing significantly reduces the amount and variety of freshwater organisms carried to ballast tanks.

Empirical evidence of a sharp reduction in intrusion risk

The true test of such regulation is the effect on the observed rate of species invasion. Since 2008, reported intrusions in the Great Lakes basin have decreased by 85%, the lowest rate in the second century. Empirical evidence indicates ballast water regulation as the overwhelming main cause, although other factors may have contributed to the sharp drop in penetration.

The Great Lakes remain vulnerable to invasion from poorly regulated sources, such as trading organisms (aquarium pets, live food, ornamental garden plants, food markets, etc.), but this study remains vulnerable. A strategy that highlights the potential benefits of internationally coordinated evidence-based management.


Almost clean 10 years later, new alien species will emerge in the Great Lakes


For more information:
Anthony Ricciardi et al, Vector Control, reduces species invasion in the world’s largest freshwater ecosystems. Conservation letter (2022). DOI: 10.1111 / conl.12866

Provided by
McGill University

Quote: To stop the tide of invading species in the Five Great Lakes (March 11, 2022), https: //phys.org/news/2022-03-stemming-tide-oxidant-species-great.html to March 2022 I got 11 days.

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Stop the tide of invasive species in the Great Lakes

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