Fishery landings and catch-at-age revisions for Atlantic Herring (Clupea harengus) in NAFO divisions 4RSw over the 1973-2021 period

Abstract

This document presents a revision of commercial fishery landings and catch-at-age estimates for Atlantic herring (Clupea harengus) in NAFO division 4R and unit area 4Sw over the 1973- 2021 period. Landings were re-extracted from original data sources to build continuous historical series and identify discrepancies with values used in previous assessments. A standardized and reproducible algorithm was developed to assign biological samples to landings based on spatial, temporal, and gear-type proximity. This approach was then applied to update annual catch-at-age estimates for spring- and fall-spawning components. Results indicate only minor changes in landings data and catch-at-age estimates relative to the original approach, with more noticeable differences at younger ages. Nevertheless, comparisons with earlier assessments suggest minimal impact on overall age composition and cohort tracking. These revised inputs aim to enhance the transparency and reproducibility of catch-at-age estimates for future stock assessments of herring in 4RSw.