Processed Zooplankton Abundance and Water-Mass Composition Data from the Northeastern East China Sea Shelf, 2019–2025

This dataset contains processed zooplankton abundance and water-mass composition data collected from the northeastern East China Sea shelf between 2019 and 2025. The dataset supports the analyses presented in the associated study examining nonlinear and taxon-specific zooplankton responses across hydrographic transition zones formed by multiple interacting water masses. The archived data include water-mass contributions summarized at 10-m depth intervals for Changjiang Diluted Water (CDW), Yellow Sea Cold Bottom Water (YSCBW), Tsushima Warm Current Bottom Water (TWCB), and Tsushima Warm Current Surface Water (TWCS). Zooplankton data are provided as annual taxon-level abundance summaries and as taxon-specific abundance summaries across gradients of water-mass dominance (WMmax) and Shannon mixing entropy (H). Processed vertical distribution summaries for Calanus sinicus and Calanus copepodites under contrasting YSCBW conditions are also included. The archive additionally provides a data dictionary, definitions of abbreviations and derived hydrographic metrics, and R code for processing and visualization of the archived summary datasets. A fixed random seed is specified in the accompanying code to facilitate reproducible implementation. The deposited files represent the processed data products relevant to the analyses reported in the associated study. Full-resolution environmental and hydrographic profiles, geographic coordinates, acoustic observations, and additional survey variables outside the scope of the present study are not included in this release. Keywords: Zooplankton; Water masses; Marine ecotone; Hydrographic mixing; East China Sea; Yellow Sea Cold Bottom Water; Calanus sinicus; Mixing entropy