Data files included within the supplementary information folder for the paper ‘Catch per unit research effort: sampling intensity, chronological uncertainty, and the onset of marine fishing in historic London’ (Orton, Morris, and Pipe, O  pen Qu  aternary). Data are derived from a snapshot of the MOLA (Museum of London Archaeology) internal database in October 2013. Unfortunately the raw data cannot be included for commercial/copyright reasons, and the files included here have been cleaned, filtered, and ‘anonymised’ (in the sense that original site codes have been replaced by arbitrary numbers) prior to upload. Data from sites not included in the study - due to location, dating, or complete lack of suitable wet-sieved zooarchaeological data - are excluded from a  ll  tables. Otherwise, all contexts, samples, and zooarchaeological specimens are included, whether they make it into the eventual analysis or or filtered out in the associated R code. For this reason, the numbers of records in each table may not always match those mentioned in the text.