Posted by: Vicki Burns | September 24, 2018

Industrialized Agriculture, Toxic Blue-Green Algae and Lake Winnipeg

I have been writing a blog about Lake Winnipeg and blue-green algae since 2010 but many others, including renowned scientists, have been issuing reports and research papers for years. I will highlight some of that research in subsequent paragraphs but the main point I am trying to make is that in spite of well-respected and accepted science, we are continuing to allow expansion of practices that we know will worsen our problem with often toxic blue-green algae in our lakes.

fishshoreline Gimli EICD

Gimli, Manitoba September 2017

In 2011 the Manitoba government announced that they were establishing a goal of reducing the phosphorus in the south basin of Lake Winnipeg by 50%. This decision was based on research by Peter Leavitt et al “Sudden ecosystem state change in Lake Winnipeg, Canada, caused by eutrophication arising from crop and livestock production during the 20th century”. In this paper the researchers document the rapid increase in livestock production in Manitoba (from 2 million to 8 million pigs in the 1990s) and the subsequent increase in amount of phosphorus and nitrogen getting into Lake Winnipeg.

pigs in large barn
In 2012 “The rapid eutrophication of Lake Winnipeg: Greening under global change”, Schindler, McCullough &Hecky, Journal of Great Lakes Research , documents the almost doubling in size of algal blooms in Lake Winnipeg since the 1990’s and attributes that to two factors; “rapidly increased livestock production and use of synthetic fertilizer in the Red River Valley, with smaller contributions of phosphorus from the city of Winnipeg and other human development in the Red and Winnipeg river basins. The second factor is the increased frequency and intensity of spring floods in the Red River watershed in recent years, which have greatly enhanced the transfer of phosphorus from the landscape to the lake, as well as slower increases in nitrogen”.
Jump forward to 2018 and we see that our current provincial government is encouraging the expansion of the industrial hog industry in Manitoba by loosening regulations required to build or expand existing hog operations. Encouraging the development of organic or small scale hog farms would be a sustainable way to create a long term hog industry in our province that would decrease threats to our lakes. But to open the doors to more industrial operations where thousands of pigs are held under one roof and where their liquid manure needs to be disposed of on spread fields, potentially contributing more phosphorus and nitrogen in run-off, is simply wrong.
We have made virtually no progress towards the goal of cutting the amount of phosphorus in the south basin of Lake Winnipeg since 2011 and it’s not likely that we will make progress as long as we continue to allow policy decisions that fly in the face of what science is telling us.



  1. Micro-organisms used to keep a water body healthy, oxygenated and free from algae. With industrialized ag and meat industry growth we changed the balance between Micro and and Macro Nutrients (N and P). This limited the growth of micro organisms in the water (which need both macro and micro nutrients) to take care of excess macro nutrients resulting in the macro nutrients going to toxic algae particularly blue green algae.

  2. Only seen the very nasty blue/green algae in Alberta – never been to Manitoba, except for a very quick road trip. Anything you can do NOW is important. It is very aggressive and kills all.

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