ANTHROPOGENIC (HUMAN) CAUSES OF MASSIVE FISH KILL

The best lies have some truth within them. In other words suggesting that aliens from outer space are attacking fish species within lake Erie, probably wouldn't sell. On the other hand suggesting that the fish kill was due to natural causes, namely "lake inversion" is a winner because it is half right. "Lake inversion" is indeed a scientifically recognized phenomenon. Also stating that there is less oxygen at the bottom of the shallower areas of Lake Erie is correct. The term is anoxic.

A retired, world recognized Biologist and Lake Erie fisheries expert advises in regards to major fish kills due to either "lake inversion" or anoxic water that "...it never happened before Europeans came to North America". Even more bluntly he states that the fish kills in the 60's & 70's as well as in the last decade are "...all caused by humans...".

The key is what has caused these oxygen depleted "dead zones" on the bottom of Lake Erie as well as in shallower parts of Lake Huron and Lake Michigan. Intensive agriculture is a part of it. Phosphates were removed from laundry detergents in order to reduce the sudsing and foaming in receiving waterways below sewage treatment plants. Concrete holding tanks were built on farms in order to reduce direct drainage of nitrogen, phosphates and more from animal sewage. Finally many sewage treatment plants added tertiary treatment which again helped reduce phosphate loading from industrial sources as well as from human sewage. All these actions helped.

Enter global warming/climate change. Warmer weather and water, longer each summer combined with ever more people, human sewage and animals grazing still in floodplains and or with direct access to waterways. Woolwich Township need only look along the Conestogo River where the expressway crosses it just south of St. Jacobs to see that. The crap from those cattle and thousands more is not removed from the Conestogo and then into the Grand River and finally into Lake Erie. Hence we now have large, toxic algal blooms on many local water bodies as well as on Lake Erie.

These algal blooms die and sink to the bottom. They then begin to decompose. It is this decomposition which requires oxygen and removes it from the water. The larger the algal blooms originally on the surface, the more the decomposition on the bottom and the greater the oxygen depletion of the water. Then when you have a "lake inversion" with colder water sinking and displacing the bottom water, the oxygen depleted water rises proving fatal to fish. Other biological/chemical phenomenon may also be at work. H.R. suggests that this decomposition on the bottom of the lake could also be liberating phosphates, methane and or heavy metals on the bottom. These could all be exacerbating the toxicity of the anoxic water.

The bottom line is very simple. Major fish kills are not caused by natural "lake inversions". They are caused by human pollution. This started in the 60's and was responded to sucessfully at first. It's back and the Ontario Ministry of the Environment know full well it's caused by us. The question is whether the M.O.E. will continue to deceive or not. You can fool some of the people some of the time but.... .