Each month, we highlight research MDC uses to improve fish, forest, and wildlife management.
Protecting Aquatic Life
Fish Kill and Pollution Program
You’ll know a fish kill when you see or smell it — the sudden appearance of dead fish in a lake or stream.
“Half of reported fish kills are caused by natural events like temperature extremes, lack of oxygen in the water, and disease,” said MDC Scientist Rebecca O’Hearn. She heads up Missouri’s Fish Kill and Pollution Investigation Program. “The rest are caused by pollution — human and livestock waste, chlorinated drinking water, or chemical spills,” she said.
Every year, MDC handles around 100 fish kill and other water-quality events that pose a threat to fish, wildlife, and recreation.
The program celebrated its 80th anniversary in 2019. “MDC initiated it in 1939 to tackle the state’s significant pollution problems at the time,” said O’Hearn. The program works in collaboration with the Missouri Department of Natural Resources (DNR), the state’s pollution control agency, to investigate, mitigate, and enforce Missouri’s Clean Water Law (MCWL) for pollution incidents.
82-year effort has helped reduce fish kill and water pollution incidents
She noted that managers can prevent or solve many natural fish kills in ponds and lakes by maintaining oxygen levels through algae control, including reducing nutrient inputs or applying algaecides or aeration.
When fish kills are caused by a pollutant, more solutions are required to remedy the problem.
“When a violator can be identified, they are charged the cleanup costs and monetary damages, which compensate the state for losses of fish and wildlife,” O’Hearn said. Depending on the circumstances leading to the fish kill, DNR may also assess a penalty for violations of the MCWL.
“MDC uses compensated damages for fish and wildlife recovery and improvement of aquatic habitats,” O’Hearn said.
To report fish kills and pollution, see Be the Solution below.
This Issue's Staff
Angie Daly Morfeld