Fish Kill Event - Whitewater Creek

Dead fish were found from Section 18, T88N, R1E of Dubuque County downstream to Section 10, T86N, R1W of Jones County. The length of stream where dead fish were assessed was 23.8 miles (125,918 feet). Cause of kill under investigation, suspected to be ammonia toxicity associated with manure run-off. I was notified of this kill event at 7:35 am on Monday, September 19, 2016 by Mark Winn with DNR Fisheries as he received a voicemail message from Sue Miller (DNR-ESD) regarding the kill that was recorded on Manchester Fisheries cell phone on the morning of Sunday, September 18. Sue noted (in the message) that she was informed of the kill on late Saturday and was investigating the kill as of Sunday morning. We arrived on-site at Lone Pine Road at 9:58 am on Monday morning where we confirmed dead fish. We spent the remainder of September 19 determining the extent of the kill as dead fish were found over a 23.8-mile length of stream across 2 counties. I determined the reach to be incompletely accessible given the length of kill at more than 23 miles, extreme stream turbidity that prevented observing more than a few inches into the stream, and steeply sloped and heavily vegetated banks across an expansive area of private land. Therefore we followed procedures for fish kill assessment on incompletely accessible streams. The stream flows appeared to have been much higher in previous days as near-bank vegetation was lying-over and a high water flow line was visible more than 5 feet above the water level at the time of investigation. Dead fish were in many cases found in heavy vegetation at a distance of 10 to 20 feet from the water line and the smell of decomposing fish was strong from Lone Pine Road down to Filmore Recreation Area. Decomposition of fish was advanced with fly larvae heavily infested on most carcasses, so species could not be readily identified in all cases. However, genus was easily recognizable for most carcasses. Based on the extent of decay it is probable that the fish kill occurred during the previous week. We identified the following 17 fish species dead in the kill area: Bluegill, Bluntnose Minnow, Central Stoneroller, Channel Catfish, Common Shiner, Creek Chub, Fantail Darter, Gizzard Shad, Green Sunfish, Highfin Carpsucker, Hornyhead Chub, Northern Hogsucker, Redhorse (unidentified species), Smallmouth Bass, Spotfin Shiner, Stonecat, White Sucker. This was an extensive fish kill of large magnitude that appeared to have occurred during a period of high stream discharge. It is likely that this was the most significant (numbers of fish, monetary value, and lost recreational value) fish kill that I have investigated during the past 14 years. Valuation and estimates of fish lost are grossly underestimated by this investigation given the extent of fish decay, high stream discharge, and high stream turbidity.