Eighteen years of capture-mark-recapture (CMR) data of grey seal pups, Halichoerus grypus, from Pembrokeshire, Wales.

Eighteen years (1954-1972) of capture-mark-recapture data of 245 grey seal pups marked with identification tags in Wales. The data was obtained from paper files held by NRW and supplied originally West Wales Field Society and includes information on the location and number of animals marked in each year including sex and age estimations.