Editor’s note: The video above is an entire webinar, skip to one minute for the beginning.

ROCHESTER, NY (WROC) — A webinar Tuesday was done by the International Joint Commission’s (IJC) science advisory board about the stressors now and expected in the future.

The report shows how difficult the future may be when it comes to protecting the Great Lakes to these stressors. Based on population and amount of stressors, both Lake Erie and Lake Ontario are victims of multiple stressors that interact with each other in different ways.

For now, the focus in this report was on how these stressors interact with each other. There are something like over 50 stressors for the Great Lakes, but the scientists involved whittled them down to seven (in no particular order):

  1. Invasive species
    • Mussels, lampreys, gobies, asian carp, phragmites
  2. Toxic chemicals
    • Persistent organic pollutants, PCB, DDT, PFAS, mercury, pharmaceuticals, personal care products
  3. Nutrients
    • Phosphorus, nitrogen, silica
  4. Climate Change
    • Warming, precipitation changes
  5. Habitat Loss
    • Wetlands
  6. Fish harvest
    • commercial
  7. Pathogens
    • VHS, other viruses, fecal indicator bacteria

This IJC board is focusing on how to reduce these stressors with the full understanding of how it may impact the lake in positive and negative ways. Each stressor can have different impacts, not only on other stressors but also over different areas and different time scales.


Farming practices as well as lawn care will commonly use phosphorus that, in high concentrations, can increase the amount of algae in bodies of water that can lead to Harmful Algal Blooms (HABs) and other impacts. This can have a synergistic and additive impact as climate change continues to occur. Climate change will increase extreme precipitation, which increases runoff that can sweep more phosphorus into the body of water. It will also increase water temperature, which is key to development of HABs.


Most may think that all stressors, when connected, will make things worse. This board is looking to prove that wrong and show how reducing certain stressors can increase other stressors.


A reduction in phosphorus loading may have an unintended consequence of increasing the concentration of certain toxins within the wildlife ecosystem. Here’s why: As phosphorus enters a water system, it enhances and increases the amount of algae. That algae is a food source for the bottom of the food chain. This will increase the number of fish and certain toxins, like PCB’s that were banned in the 1970s, will be less prevalent within the fish. If the amount of phosphorus is reduced, there may be a smaller food source and less fish. The lower amount of fish could mean a higher concentration of PCB’s within the fish.


Other solutions include:

  • Reducing stressors that are the most understood and do not have impacts on other stressors.
  • Focusing on spacial and temporal scales
  • Focusing on climate change, the number one stressor that has the biggest role on enhancing other stressors

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