WBAT data, Catch, Environment data sheet

This study was conducted to ascertain the adult density, spawning timing, and biological characteristics of Pacific herring (Clupea pallasii) entering Jinhae Bay, South Korea, in winter, a major spawning ground for the species. A wideband autonomous transceiver (WBAT) was operated from November 2022 to March 2023, a gillnet survey was conducted, and environmental DNA (eDNA) was analyzed. In WBAT monitoring, C. pallasii school signals were detected predominantly from mid-January to mid-February, and C. pallasii was the dominant species in gillnet catches during the same period. When the reproductive maturity of captured females was assessed, most were in the ripe or spent stage, indicating the main spawning period. In eDNA analysis, C. pallasii DNA levels peaked in the surface and bottom layers in mid-January and then declined gradually. Overall, entry to the spawning grounds begins in late December, peak spawning occurs in mid to late January, and subsequent departure from the grounds follows. Acoustic, catch, and eDNA survey techniques were integrated to analyze the timing of appearance, density, and spawning ecology of C. pallasii, and the findings are expected to inform future management of C. pallasii resources and protection of spawning grounds.