This data set comprises biological data collected from commercial shellfish landed from Irish vessels. The data is collected under the Data Collection Framework (REGULATION (EU) 2017/1004 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 17 May 2017 and COMMISSION DELEGATED DECISION (EU) 2021/1167 of 16 July 2021). Fisheries occur in the waters around the Irish coast in ICES Sub areas 6 and 7. Data on length, weight, sex and maturity is recorded for crustacean and molluscan species, i.e. Homarus gammarus, Cancer pagurus, Palinurus elephas, Pecten maximus and Buccinum undatum. This data has been recorded since 2013 from various ports, co-ops and shellfish processing facilities. A key objective of fisheries research is to provide good information on the state of fish stocks. This information is collected through various sampling programmes and the data are used to provide advice on the sustainable management of fish stocks, upon which the industry depends.