Fish kills – what you can do to help
Imagine this: You are relaxing on the beach on a nice sunny day in mid-June. The loons are calling as the water gently laps at the shoreline. Your kids are jumping off the dock and there is a pungent smell in the air. Wait, what?!
You are smelling dead fish, technically defined as a fish kill: a die-off of at least five fish of the same species in close proximity in space and time. Fish kills in Minnesota are widespread and can lead to public health concerns, costly cleanups, and potentially significant declines in fish populations. At a minimum, fish kills impact our perspective of what it means to be a pristine Minnesota lake. While some of these events are the result of serious fish diseases, many are associated with natural causes, such as warm water, low oxygen, and algae blooms. However, these so-called natural processes can be heavily influenced by human activity, such as climate change, nutrient runoff, agriculture, and urbanization to name a few.
Researchers at the University of Minnesota (UMN) are trying to better understand the causes and trends of fish kill events to inform proactive and adaptive management strategies – and we need your help. An estimated 500 fish kill events occur each year in Minnesota, yet only an average of 35 per year were documented in the Minnesota Department of Natural Resources’ (DNR) primary database since 2003. Lake users calling the State Duty Officer or their local DNR office report the majority of these events; however, inconsistent information and limited reporting frequency present challenges for data analysis.
To standardize and simplify reporting for lake users and biologists alike, there is a new and easy-to-use website: http://z.umn.edu/fishkill. On this site, you can see past fish kill reports and report new events. After answering a few simple questions, such as what species was affected and how many, what was the weather like, etc., the event is geo-referenced and reported. Researchers at the UMN are notified of new fish kill events daily and share that information with the DNR. If the event warrants further investigation, veterinary students or biologists will be sent to the site to collect samples and diagnose the cause of death.
With your help, UMN researchers and fisheries managers can better protect the health and sustainability of Minnesota’s fish populations.
Minnesota fish kill facts 
- June is the most common month to observe a fish kill
- Bluegills and bass are found in 44% of fish kills in Minnesota
- 33% of fish kills are associated with environmental factors and 23% are associated with infectious diseases
- Fish kills are not randomly distributed, they are more likely to near urban areas, although this may be reporting bias
Data from fish kill events reported to DNR from 2003-2013
