Shark likely to blame for taking chomp out of DFO ocean glider off N.S. coast

Fisheries and Oceans Canada researchers say one of theirocean gliders likely had a run-in with a shark after it was recovered severely damaged over the weekend nearly 300 kilometres off the coast of Halifax.

The rocket-shaped device had been deployed for about two weeks when researchers atDFO received a distress alarmbecause the glidercould no longer be navigated along its route.

It wasn't until Saturday when a research ship was able to recover it that DFOcouldassess the damage.

"Whatever hit it, whatever caused it to start [navigating] very poorly happened about 300 metresbelow the surface," said Clark Richards, a research scientist with DFO.

"There wasn't a boat, it was certainly an animal of some kind. And the bite marks also are a pretty good clue that it wasn't just a whale or something playing with a toy that it found."

Richards said the glider was on a mission along what researchers call the Halifax route gathering data on seawater propertieslike temperature, salinity and the amount of small particles in the ocean. This particularmodel cost about $250,000 when it was purchased eight years ago,he said.

The glidersdon't have a propulsion system so they move through the water by changing their buoyancy. With the help of small wings on the gliders' bodies,researchers are able to slowlynavigate the devicesthrough the water.

The Halifax route takes the gliders out around 300 kilometres from the shore, so it was nearly at the farthest point in its journey when it sent out the alarm signal.

Strong enough to bend aluminum frame

Along with taking off a couple of the plastic wings on the glider, whatever attacked it also bit into the equipment's body.

"The glider weighs about 60 kilograms [and] whatever grabbed on to that glider had enough strength that it bent that aluminum frame," he said.

He added that, thankfully, the glider is salvageable. Once it's off the research ship, it will be sent back to the manufacturer for repairs and back out into the oceanfor more data collection.

This isn't the first time in recent years a glider has lost a fight against a shark. In 2021, a glider listening for tagged halibut was disabled by a shark attack near Sable Island.

That led to an emergency76-hour effort to retrieve the equipment.

Despite that, shark-proofing the gliders is not on the table.

"[The gliders] are not much bigger than a large seal would be," Richardssaid. "We colour them yellow, so they certainly look different, but there isn't anything I know of that would actively discourage an interaction."

The gliders actually receive pings from tagged animals, like seals and fish, which is why Richards said researchers don't necessarily want to scare marine life away from their equipment.

"We always know if you put something in the ocean, there's a risk,for all kinds of reasons,that you might not get it back," Richards said.