Intraguild predation in sympatric seals and the effect on a declining population (dataset)

Evidence for grey seal predation of marine mammals has been collected from direct observations of predation events, and indirectly through strandings data which have been assessed for cause of death.

The attached data files underpin the publication “Intraguild predation in sympatric seals and the effect on a declining population”. The following file types and formats are included:

1. Grey seal predation observations collected by citizen-science and collated by the Sea Mammal Research Unit, University of St Andrews. Guidelines issued by the University of St Andrews School of Biology Ethics Committee for the collection, storage, and analysis of citizen science data were followed and ethical approval was granted (reference BL15073). Data are stored in a csv file which can be opened in various programmes, including Microsoft Excel (observations.csv).

Observational reports were assessed for the likelihood the observed interaction was a predation event:
Definite – both the kill and subsequent feeding were captured in photographs and/or videos
Likely – the kill was not captured (scavenging could not be ruled out)
Possible – detailed descriptions without photograph/video evidence

2. Marine mammal strandings data collected and assessed by The Scottish Marine Animal Stranding Scheme, University of Glasgow. Data are stored in a csv file which can be opened in various programmes, including Microsoft Excel (strandings.csv).

Dead seals were assessed for the likelihood that the cause of death is grey seal predation:
Definite – directly observed predation
Likely – pathology is most consistently explained by grey seal predation
Probable – pathology is consistent with grey seal predation but other causes of death are plausible
Possible – pathology would not be inconsistent with grey seal predation but there were insufficient data to exclude other causes of death

Harbour porpoise carcasses with pathological attributes indicative of grey seal predation were scored possible grey seal predation.