Report of the Workshop on Predator-prey Interactions between Grey Seals and other marine mammals (WKPIGS)

A one-day Workshop on Predator-prey Interactions between Grey Seals and other marine mammals (WKPIGS) focused on predatory behaviour of grey seals (Halichoerus grypus) towards other grey seals, harbour seals (Phoca vitulina) and harbour porpoises (Phocoena phocoena) in European waters was convened in April 2017. The workshop was chaired by Nora Hanson, UK, Abbo van Neer, Germany, Andrew Brownlow, UK, and Jan Haelters, Belgium. It was attended by 30 scientists from organisations in six nations across Europe, and the USA and aimed to define and harmonise the pathological indicators of grey seal predation events across nations and to collate data on the prevalence and distribution of such events. A further objective was to discuss methods to aid in detection of predation events and potential population-level consequences of reported incidences. The following report summarises the presentations and discussions held in each of four workshop sessions: pathological indicators, distribution and prevalence, population consequences and research priorities.