Information on maximum dive depth and the time spent at various depths was obtained from 49 Shags Phalacrocorax aristotelis. On average, the maximum dive depth was 33–35 m; the overall maximum was 43 m. Shags dived repeatedly to the same depth and spent c. 55% of the time between 25 and 34 m which indicated that they were foraging close to the seabed. About 46% of the time underwater was spent foraging and 54% travelling. Average underwater swimming speed was 1.7-1.9 m per second.