Environmental DNA (eDNA) is a non-invasive monitoring approach increasingly used to detect marine organisms; however, misunderstandings of the temporal variability in eDNA detection has limited its integration within management decisions. A clearer understanding of the periodicity (e.g., seasonality) and duration (e.g., weeks, months) of species eDNA detection is essential to optimize sampling design and data interpretation. As such, this study aims to provide a representative assessment of optimal eDNA detection windows across diverse taxonomic groups, primers, and geographic regions using eDNA metabarcoding. Coastal marine presence-absence eDNA data were collected along the Northwest Atlantic coast, in the Bay of Fundy, Scotian Shelf, and Baffin Island. eDNA detection window(s) were defined as unimodal, contiguous months having greater than 75% detection probability and were calculated for each taxon for each primer in each region. 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 18S gene in Iqaluit, Nunavut only; Results for the COI, 16S and 12S markers in Iqaluit are also available in OBIS.
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The Arctic Port of Iqaluit (ARC), Nunavut, is located at the innermost end of Koojesse Inlet within Frobisher Bay (area 11,000 km2, depth ≤ 120 m).","boundingBox":{"minLatitude":-90.0,"maxLatitude":90.0,"minLongitude":-180.0,"maxLongitude":180.0,"globalCoverage":true}}],"temporalCoverages":[],"keywordCollections":[{"thesaurus":"GBIF Dataset Type Vocabulary: http://rs.gbif.org/vocabulary/gbif/dataset_type_2015-07-10.xml","keywords":["Occurrence"]}],"project":{"title":"DFO Monthly GRDI Survey eDNA metabarcoding (18S) in Iqaluit 2019","contacts":[{"type":"OWNER","primary":false,"userId":["http://scholar.google.com/citations?user=T-75bw0AAAAJ&hl=en"],"firstName":"Kimberly","lastName":"Howland","position":[],"email":[],"phone":[],"homepage":[],"address":[]}],"awards":[],"relatedProjects":[]},"samplingDescription":{"studyExtent":"Repeated measurements were implemented at multiple levels to support the robustness of species detection patterns: spatially, with samples replicated across multiple stations within each region, and analytically, through triplicate PCRs. Seasonal variation was therefore incorporated throughout this sampling design.","sampling":"Samples (1 L) were collected once per month from 2-6 stations per region using a Niskin bottle 2-3 m below the surface (ARC: 4 stations, n = 27, May, June, August, October, & November 2019). For each station and sampling event, on average, 2-3 samples were collected from repeated deployments of the Niskin bottle (ARC: 2 field replicates on average).","methodSteps":["Site selection 2. Water collection and eDNA filtration 3. DNA extraction and eDNA metabarcoding 4. Bioinformatics and statistical analyses"]},"countryCoverage":[],"collections":[],"dataDescriptions":[],"dataLanguage":"eng","pubDate":"2026-03-30T00:00:00.000+00:00","maintenanceUpdateFrequency":"AS_NEEDED","maintenanceDescription":"","license":"http://creativecommons.org/licenses/by-nc/4.0/legalcode","dwca":{"coreType":"http://rs.tdwg.org/dwc/terms/Occurrence","extensions":["http://rs.gbif.org/terms/1.0/DNADerivedData","http://rs.iobis.org/obis/terms/ExtendedMeasurementOrFact"],"modified":"2026-07-13T09:45:30.028+00:00"},"category":["eDNA"],"approximateCounts":{"occurrenceCount":2820}}