A standardized assessment of geographic variation in size at maturity of European lobster (Homarus gammarus L.) in the North East Atlantic

Assessing size at maturity for European lobster Homarus gammarus across the North East Atlantic remains a fundamental knowledge gap for this commercially valuable fishery. This study for the first time collates existing data on physiological maturity of female European lobster H. gammarus across the North East Atlantic, including new data from Scotland, Wales, and the Isle of Man. Physiological estimates of size at maturity were undertaken using 1309 lobsters from 11 locations using a standardized methodology. Carapace length (CL) at which 50% of the sampled population had reached physiological maturity (CL₅₀) varied between populations, ranging from 82 to 92.5 mm. CL₅₀ estimates reported here are broadly similar for historic population samples in England, but estimates for Irish samples were lower than previous results. The development of a H. gammarus specific staging guide and methodology in this study enables the future comparison of potential fluctuations in female size at maturity.