TWO SHARK SPECIES INVOLVED IN PREDATION ON SEALS AT SABLE ISLAND, NOVA SCOTIA, CANADA
Between 1993 and 2001, 4906 seal corpses bearing wounds likely inflictedby sharks were examined on Sable Island, Canada. Five seal species wereinvolved: grey (Halichoerus grypus), harp (Pagophilus groenlandica), harbour(Phoca vitulina), hooded (Cystophora cristata), and ringed (Phoca hispida)seals....
| Main Authors: | , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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Nova Scotian Institute of Science (NSIS)
2010
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| Online Access: | https://ojs.library.dal.ca/nsis/article/view/3987 https://doi.org/10.15273/pnsis.v45i2.3987 |
| Summary: | Between 1993 and 2001, 4906 seal corpses bearing wounds likely inflictedby sharks were examined on Sable Island, Canada. Five seal species wereinvolved: grey (Halichoerus grypus), harp (Pagophilus groenlandica), harbour(Phoca vitulina), hooded (Cystophora cristata), and ringed (Phoca hispida)seals. Flesh wounds on seal corpses indicated that two or more shark speciesprey on seals in waters around Sable Island. Wounds were categorizedas either slash or corkscrew, with different predators identified for eachtype. Wound patterns, tooth fragments, and marks on bones indicated thatwhite sharks (Carcharodon carcharias) were involved in the slash wounds,which comprised a small proportion of attacks. Ninety-eight percent of sealcorpses, however, bore the corkscrew wounds that could not be attributedto shark species identified in attacks on pinnipeds in other regions and thesewounds are previously unreported in the literature. Circumstantial evidenceindicates that attacks by Greenland sharks (Somniosus microcephalus) wereresponsible for the clean-edged encircling corkscrew wounds seen on sealcorpses washed ashore on Sable Island.KEY WORDS: Shark Seal, Sable Island, Greenland shark, Somniosusmicrocephalus predation |
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