Zooplankton Monitoring

Jeff Kasowski
Aquatic Ecologist

Zooplankton are microscopic animals that play an important role in lake food chains.  They feed on algae to keep lakes clear and provide food for newly hatched young-of-the-year sports fish.  The type of zooplankton in a lake remain relatively stable over time.  A sudden appearance of new kinds or changes in the relative numbers of different kinds can be caused by changes in nutrient inputs, types of fish that are dominant, new aquatic invasive species like zebra mussels or spiny waterflea, or toxic substances. Zooplankton are to lakes what the canary is to the coalmine.

Zooplankton samples can be collected by trained volunteers.  When monitored monthly throughout the summer, community dynamics can be tracked.  In lakes infested with spiny waterflea or zebra mussels, relative densities of the invasive zooplankton versus the native zooplankton can be evaluated to see the impact from infestation.


•  Zooplankton sample processing and identification (following Minnesota DNR protocols)

•  Metric reports: mean monthly zooplankton densities, monthly community composition distribution, total monthly zooplankton counts

• Field collection of zooplankton

• Volunteer training for field collection

Links to more information about zooplankton:
Zooplankton Fact Sheet
Zooplankton Communities in Minnesota Lakes