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Monday, January 29 • 2:20pm - 2:40pm
SYMPOSIA-05: Investigating Fish Kills to Identify Emerging Threats and Long-term Stress

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AUTHORS. Nick Phelps, University of Minnesota

ABSTRACT. Fish kill investigations are critical to understanding threats to aquatic ecosystems, and can be an early indicator of environmental changes and emerging disease. The goal of this study was to perform descriptive and predictive analyses of fish kill events in Minnesota and to evaluate the application of advanced diagnostic methods. From 2003-2013, 225 unique fish kill events were recorded in two MN DNR databases. Reported fish kills peaked during 2007 (n=41) and the month of June (n=81) across all years. Species of the Centrarchidae family were present in 138 fish kill events, followed by Cyprinidae and Ictaluridae with 53 and 40 fish kill events, respectively. Environmental factors (32%) were the most common cause of death reported; however, 30% were due to unknown causes. To identify environmental factors related to fish kills, ecological niche models were developed to create predictive risk maps. Water temperature was the most critical factor for fish mortality, followed by changes in primary productivity, and human disturbance. Lastly, along with traditional diagnostic approaches, next generation sequencing was used to investigate five mortality events. Six viruses were identified from three events, including a novel picornavirus, astrovirus, betanodavirus, calicivirus, paramyxovirus, and the previously described bluegill picornavirus for the first time outside of Wisconsin. Identification of novel viruses is an important consideration for future fish kill investigations and understanding environmental stress in disease emergence. The results of this study can be used to improve efficient and effective investigation of fish kills and guide active environmental monitoring.

Monday January 29, 2018 2:20pm - 2:40pm CST