Estuarine cline in fish eDNA composition and ecotone between the inside and outside of locally enclosed areas

Estuaries are dynamic environments where monitoring fish biodiversity and detecting ecological change can be logistically difficult and expensive. Environmental DNA metabarcoding offers a cost‐effective alternative for biodiversity assessment. However, recent studies have shown that sharp transitions in fish eDNA composition (ecotones) can occur across boundaries of enclosed areas within estuaries. If these ecotones are strong or occur at unknown locations, they may distort spatial patterns in fish community data. This study investigated the conditions under which such ecotones form and assessed their impact on patterns of fish eDNA distribution in estuarine systems. We compared fish eDNA composition inside and outside six enclosed areas within Tokyo Bay, an estuary with a strong salinity gradient. Our spatially nested sampling design revealed that fish eDNA composition varies along the gradients of salinity and total nitrogen and differs consistently between the inside and outside of l..., , # Estuarine cline in fish eDNA composition and ecotone between the inside and outside of locally enclosed areas Dataset DOI: [10.5061/dryad.9w0vt4btp](10.5061/dryad.9w0vt4btp) ## Description of the data and file structure Estuarine cline in fish eDNA composition and ecotone between the inside and outside of locally enclosed areas Description of the data and file structure This dataset was collected for research presented in the following paper, which focuses on environmental DNA (eDNA) surveys targeting fish species: Hosokawa, S., & Homma, S. (submitted). Estuarine cline in fish eDNA composition and ecotone between the inside and outside of locally enclosed areas This study includes the eDNA composition of fish in Tokyo Bay. The dataset includes metabarcoding results. The dataset contains processed data used for analysis. Details of the sampling strategy and analysis methods are provided in the paper and supplementary information. ### Files and variables #### File: Fig-01.R **..., ,