Corkscrew seals: Grey seal (Halichoerus grypus) infanticide and cannibalism may indicate the cause of spiral lacerations in seals

A Brownlow, J Onoufriou, A Bishop, N Davison, D Thompson

Research output: Contribution to journalArticle

12 Citations (Scopus)
7 Downloads (Pure)

Abstract

Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.
Original languageEnglish
JournalPLoS ONE
Volume11
Issue number6
Early online date2 Jun 2016
DOIs
Publication statusFirst published - 2 Jun 2016

Fingerprint

infanticide
cannibalism
predation
lesion
shark
mortality

Keywords

  • Animal sexual behaviour
  • Fresh water
  • Lesions
  • Predation
  • Scotland
  • Seals
  • Skull
  • Traumatic injury

Cite this

@article{7b5c7f7f99dc4876a3bc0d66a730f0f5,
title = "Corkscrew seals: Grey seal (Halichoerus grypus) infanticide and cannibalism may indicate the cause of spiral lacerations in seals",
abstract = "Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.",
keywords = "Animal sexual behaviour, Fresh water, Lesions, Predation, Scotland, Seals, Skull, Traumatic injury",
author = "A Brownlow and J Onoufriou and A Bishop and N Davison and D Thompson",
year = "2016",
month = "6",
day = "2",
doi = "10.1371/journal.pone.0156464",
language = "English",
volume = "11",
journal = "PLoS ONE",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "6",

}

Corkscrew seals: Grey seal (Halichoerus grypus) infanticide and cannibalism may indicate the cause of spiral lacerations in seals. / Brownlow, A; Onoufriou, J; Bishop, A; Davison, N; Thompson, D.

In: PLoS ONE, Vol. 11, No. 6, 02.06.2016.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Corkscrew seals: Grey seal (Halichoerus grypus) infanticide and cannibalism may indicate the cause of spiral lacerations in seals

AU - Brownlow, A

AU - Onoufriou, J

AU - Bishop, A

AU - Davison, N

AU - Thompson, D

PY - 2016/6/2

Y1 - 2016/6/2

N2 - Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.

AB - Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.

KW - Animal sexual behaviour

KW - Fresh water

KW - Lesions

KW - Predation

KW - Scotland

KW - Seals

KW - Skull

KW - Traumatic injury

U2 - 10.1371/journal.pone.0156464

DO - 10.1371/journal.pone.0156464

M3 - Article

VL - 11

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 6

ER -