(…)Grey seals are generalist feeders, taking a wide variety of fish, mollusc, echinoderm, crustacean, and cephalopod prey (Bowen & Harrison, 1994; Hammond et al., 1994; Strong, 1996; Brown et al., 2012; Smout et al., 2013, 2014; Gosch et al., 2014). Other marine mammals are not a usual food source for grey seals, although cannibalism and predation on harbour seal pups (Phoca vitulina) has been reported (Bédard et al., 1993; van Neer et al., 2015).
In this short note, we report on four separate observations of grey seals directly predating and scavenging on harbour porpoises in the waters around Ramsey Island in Pembrokeshire, Wales. This is an unusual phenomenon that is receiving growing attention since lesions consistent with grey seal predation have been observed on stranded harbour porpoises in Belgium (Haelters et al., 2012), evidence of grey seal DNA has been found in wounds of harbour porpoises stranded on the Dutch coast (Leopold et al., 2014; van Bleijswijk et al., 2014), and direct observations of predation and scavenging have been recorded off France in the English Channel (Bouveroux et al., 2014). (…)