We present a long-term dataset of Atlantic herring (Clupea harengus) biological and catch information collected from 1974 to 2023 in NAFO Divisions 2J3KL, in Newfoundland and Labrador, Canada. Samples were obtained from commercial catches and processed by the Department of Fisheries and Oceans (DFO). Each record corresponds to an individual fish and includes catch details (date, area, locality, gear type) and biological measurements (length, whole and gutted weight, sex, maturity, gonad weight, spawning season, age). Standardized protocols were applied but have evolved through the decades.