Since 2012 all around the north Atlantic, increasing numbers of seal carcasses have been found with what are described as “corkscrew” type injuries. Researchers in Canada attributed these to sharks predating on the seals. In Scotland it was thought that ducted propellers were causing these injuries and deaths.
There were lots of theories but little evidence. Then in late 2014 researchers witnessed a bull Grey seal attack and partially eat a young Grey seal on the Isle of May off Scotland. The carcasses left behind by this bull seal all bore the distinctive “corkscrew” type injuries.
It has been known for some time that Grey seals will scavenge or kill other marine mammals such as Harbour porpoises and the smaller Common seal, but the Isle of May report was the first time they had been seen to kill and eat other Grey seals.
The Irish Seal Sanctuary has been keeping a database of dead seals found on our coast with the help of Irish people. Location, date and any visible injuries have been recorded.We have been able to free some alive from nets but we have records of hundreds of dead seals. Since 2015 we have seen an increase in the number of carcasses reported with massive tissue loss, consistent with “corkscrew” injuries. As reported from Scotland these have mostly been sub adult Grey seals. This year we have had a cluster of these carcasses from locations near Grey seal colonies. Without full veterinary post mortem examination it would be speculation to say that these animals were killed by other Grey seals. We have had a number of these carcasses post mortemed in UCD Veterinary Hospital and the injuries are consistent with being killed by a large predator. DNA analysis could possibly identify the predator. But this costs money.
Are Grey seals killing other Grey seals around Ireland?
Is it “Bull Rage”?, Cannibalism?, Hunger?
Why? This needs to be investigated.
Report: SECOND DEAD SEAL DATABASE REPORT
For further information or comment, please contact:
Johnny Woodlock Sea Fishery advisory Group.I.S.S.
Brendan Price Chair, Irish Seal Sanctuary
Patrick J Pollock BVMS Cert(ES) FHEA DipECVSkMRCVS