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Use of environmental DNA to detect grass carp spawning events

August 27, 2020

The timing and location of spawning events are important data for managers seeking to control invasive grass carp populations. Ichthyoplankton tows for grass carp eggs and larvae can be used to detect spawning events; however, these samples can be highly debris-laden, and are expensive and laborious to process. An alternative method, environmental DNA (eDNA) technology, has proven effective in determining the presence of aquatic species. The objectives of this project were to assess the use of eDNA collections and quantitative eDNA analysis to assess the potential spawning of grass carp in five reservoir tributaries, and to compare those results to the more traditional method of ichthyoplankton tows. Grass carp eDNA was detected in 56% of sampling occasions and was detected in all five rivers. Concentrations of grass carp eDNA were orders of magnitude higher in June, corresponding to elevated discharge and egg presence. Grass carp environmental DNA flux (copies/h) was lower when no eggs were present and was higher when velocities and discharge increased and eggs were present. There was a positive relationship between grass carp eDNA flux and egg flux. Our results support the further development of eDNA analysis as a method to detect the spawning events of grass carp or other rheophilic spawners. 

Publication Year 2020
Title Use of environmental DNA to detect grass carp spawning events
DOI 10.3390/fishes5030027
Authors Cari-Ann Hayer, Michael F. Bayless, Amy E. George, Nathan Thompson, Catherine A. Richter, Duane Chapman
Publication Type Article
Publication Subtype Journal Article
Series Title Fishes
Index ID 70212864
Record Source USGS Publications Warehouse
USGS Organization Columbia Environmental Research Center