| The bidimensional diffusion pattern of environmental DNA (eDNA) was investigated by analyzing itsconcentration in juvenile amphidromous Cottus fishes (C. hangiongensis and C. amblystomopsis) using real-timequantitative polymerase chain reaction (qPCR) assay. Environmental water samples were obtained from the left bank,center flow, and right bank of the mid-sized Ohno River, Hokkaido, Japan. at five cross-sectional lines situatedbetween 50 m and 1,000 m from the mouth of the river. The sampling was conducted three times between June andJuly 2019. When compared with the results of direct capture conducted during the same time, the eDNA concentrationrose in direct proportion to the number of Cottus fishes. The correlation coefficient reached its highest level when itwas calculated with the eDNA concentration and the number of fish collected 550-800 m upstream, withoutconsidering diffusion in the transverse diffusion. Thus, eDNA sampling in mid-sized rivers would be more effectiveif conducted separately for each bank and the center flow. |
