Spatial and temporal variability of common cuttlefish, Sepia officinalis, L. spawning grounds off North Europe

Spatial and temporal dynamics of common cuttlefish, Sepia officinalis, spawning at north European shores was studied using data collected by the Cephalopod Citizen Science Project, Seasearch between 1995 and 2021 and a range of other internet sources for the same period. Reproduction begins in the western English Channel in March and gradually progresses eastward following water warming, attaining the Netherlands in May, when peripheral spawning grounds expand north to Norfolk and the Irish Sea. Despite a thermal regime favourable for egg development existing around the UK and Ireland, spawning is normally restricted to the English Channel and southernmost North Sea with egg masses occasionally observed as far north as Isle of Man and Norfolk.