CANADIAN SHARK ATTACK REGISTRY

Autonomous glider disabled by white shark near Sable Island

Case number: 26
Date: 2021-09-12
Location: Sable Island, Nova Scotia
Incident type: Attack on object — Code: PRE
Species (Suspected): White shark (Carcharodon carcharias)
Possible cause(s): Acoustic or physical attraction (Provoked)
Result: Device disabled
Status: Confirmed
Description: An Environment and Climate Change Canada autonomous ocean glider operated by the Ocean Tracking Network (Dalhousie University) was attacked and disabled by a large shark 200 km east of Halifax. The glider was monitoring the movements of Atlantic halibut that were tagged with acoustic transmitters by DFO when the shark punctured the aluminum rudder module.

“It must have been a pretty big and powerful shark because it managed to penetrate three millimetres or more with teeth marks into the aluminum base of what’s solid aluminum.”
— Dr. Fred Whoriskey (Ocean Tracking Network)

The drifting glider, which was still able to transmit its position, was recovered for repairs after 72 hours. The bite marks were examined by Fred Whoriskey of the Ocean Tracking Network who also swabbed the glider for environmental DNA traces in an attempt to identify the shark species. It was reported in November that a second glider was also attacked by a suspected white shark: “Fred Whoriskey, executive director of the Ocean Tracking Network (OTN) at Dalhousie University, has had two Slocum gliders — eight-foot autonomous aluminum research instrument platforms — attacked and damaged by probable white sharks in waters off Nova Scotia².”

Assessment: The shark may have been inadvertently attracted and provoked by the sound of the propellers or electronic signals emanating from the autonomous glider. It may also have been attracted by the outline (shadow) and movement of the glider, which was then ‘tasted’ as potential prey or attacked as a possible intruder.
References:
¹ ‘Big and powerful’ shark attack left ocean glider adrift off Nova Scotia for days. CBC News. 17.09.2021. Online.
² Dal’s university veterinarian was on a routine dive near Halifax. Then a great white shark spotted him. Dal News. 15.11.2021. Online.
(Background) Glider SG609. Photo by NOAA AOML (Public domain)
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Misrepresented and misunderstood, sharks play a critical role in North Atlantic ecosystems, but they are under increasing threat due to their unfair reputation, pollution, and a lack of public awareness. Please donate to help us study and protect the sharks of the St. Lawrence and Atlantic Canada before it’s too late.Donations to ORS, an all-volunteer charitable not-for-profit organisation, are tax deductible in Canada. Canada Revenue Agency #834462913RR0001

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Misrepresented and misunderstood, sharks play a critical role in North Atlantic ecosystems, but they are under increasing threat due to their unfair reputation, pollution, and a lack of public awareness. Please donate to help us study and protect the sharks of the St. Lawrence and Atlantic Canada before it’s too late.Donations to ORS, an all-volunteer charitable not-for-profit organisation, are tax deductible in Canada. Canada Revenue Agency #834462913RR0001

DONATE

“Fear and indifference bite deeper than any shark.”— Jeffrey Gallant, St. Lawrence Shark ObservatoryTax deductible in Canada
CRA #834462913RR0001DONATE