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Oxygen Levels in Fish Raceways

Data from fish raceways show changes in oxygen levels as the water passes through raceways containing large fish populations and over weirs that aerate the water. 

Iowa DNR Fish Hatchery

Possible Guiding, Compelling and/or Anchoring Questions

What does the graph show? 
What is happening to cause the values to change?

Classroom Suggestions

  • Carrying Capacity: The amount of fish that can be effectively raised depends upon sufficient oxygen levels in the water, so stocking rates are adjusted to match the dissolved oxygen (DO) available. Young, fast growing fish require higher DO levels than older fish. 
  • The bacteria that feed on feces and algae also alter the DO used in the raceway.
  • Adaptations to Habitat: Trout have high oxygen needs and thrive in cold, fast moving streams.
  • Additional Questions:
    • Why is supplemental oxygen needed in modern aquaculture?
    • How does pressure affect dissolved oxygen levels?
    • Why is water temperature important?
    • How does Le Chatelier’s Principle help us to make predictions?
    • How do weirs work? What are their limitations?
    • What is gas bubble disease, how is it prevented, and how is it tied to human health?

Related Resources

Iowa Core Alignment


Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales

Credit Info

Submitted by Diane May

Photos, Data Tables, and Graphs by Diane May

Data collected by DNR staff


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