Fish Kills in Iowa from Manure and Other Causes
Fish Kills in Iowa from Manure and Other Causes
Both the Iowa Department of Natural Resources (DNR) and the press seem to measure the pollution of our rivers, lakes and streams by the number and size of fish kills. While the sight of bloated dead fish floating in the local stream is certainly a graphic reminder that pollution kills, the "dead fish litmus test" often gives a false impression to the public about the true nature and scope of pollution in our surface waters.
How often does a press release about a manure spill end with the reassuring statement, "while xxx thousands of gallons of manure were spilled into the creek, no dead fish were seen". The clear implication incorrectly being, no harm, no foul. The graphic nature of dead fish has been both a blessing and a curse to the environmental community. While it certainly raises public awareness (at least in the short term), it ignores the chronic effects on the aquatic ecosystem of over application and misapplication of both commercial fertilizer and animal waste.
Perhaps "no dead fish were seen" because the stream had not recovered from the last manure spill, or perhaps the stream had become so degraded over time from algae and low dissolved oxygen (both of which can result from manure runoff), that the fish were simply unable to be there anymore.
Listed below are links to several maps, tables, and database files describing manure spills and fish kills in Iowa for the past decade. Note: The Access file is very large; patience and a fast internet connection will be needed to download this file.
2007 Manure Spills and Fish Kills
Map of All Fish Kills in Iowa (JPEG 260 Kb)
Map of Known Manure-Caused Fish Kills in Iowa (JPEG 250 Kb)
Table of Fish Kills - 2002 (Excel 64 Kb)
Table of Fish Kills - 2003 (Excel 94 Kb)
Database of Fish Kills - 2004 (Access 13.4 Mb)