DFO Monthly GRDI Survey eDNA metabarcoding (16S) in the Bay of Fundy 2019-2021

Most marine species exhibited short eDNA detection windows (1–2 months). The optimal sampling periods and durations were conserved among closely related species, highlighting the importance of considering biological traits when designing and interpreting eDNA studies. Additionally, primer choice influenced the optimal detection periods, with higher seasonal variation in community composition and detection rates using universal COI and 18S primers compared to fish 16S and 12S primers.

These results demonstrate that ignoring seasonal variation may cause false negatives, inefficient sampling, and reduced data comparability across independent studies, emphasizing the need for temporal considerations when designing eDNA studies. Thus, we propose a set of guidelines aimed at the development of optimal sampling designs for coastal ecosystems and the interpretation of trends across datasets. This dataset is for the 16S mitochondrial gene in the Bay of Fundy (BoF) only; Results for the COI, 18S, and 12S markers in the BoF are also available in OBIS.