Thu. May 26th, 2022

Researchers in Halifax have recovered a number of research data that have been lost on the seabed off Nova Scotia for 3½ years.

The notable retrieval includes 19 hours of video from a camera attached to a gray seal that was lost in 2018 and was pulled up in fishing gear this summer.

“I was shocked, absolutely shocked,” said Department of Fisheries and Ocean biologist Damian Lidgard.

Not only did they restore the camera, it still works and will be relocated next month.

Lidgard had attached the device to a young male gray seal on Sable Island on 31 December 2017.

The camera mounted on this male gray seal on December 31, 2017 disappeared in 2018. The camera was discovered this summer, and researchers were able to download hours of high-resolution video and other data. (Damian Lidgard / Department of Fisheries and Oceans / Ocean Tracking Network)

He was hoping to see the male come ashore where he could easily recover the camera and another built-in sensor that records dive depth, temperature, acceleration and other data.

“Basically for the next three or four weeks, every single day, I searched for Sable looking for that man and never found him,” Lidgard said.

The unit probably fell off the seal when it melted in the spring.

Where are they going? What do they eat?

The $ 10,000 camera was deployed as part of an Ocean Tracking Network research project to track the movements of gray seals from the giant Sable Island colony. Researchers want to know where they are going and what they are eating.

The instrument is believed to have been lost until this summer, when it was practiced off the seabed by Arctic Endurance, a Clearwater Seafoods vessel fishing for surf mussels on Banquereau Bank.

The Clearwater surf mussel crew found the find

A crew member on board contacted the Australian manufacturer, Customized Animal Tracking Solutions (CATS).

The company contacted Lidgard and asked if it was part of his research project. A crew member from Arctic Endurance brought it ashore and handed it over to Lidgard.

“There were some marks on the camera, but overall it was in very good shape,” he said. “My first impression was that it survived remarkably well since it has been at the bottom of the ocean.”

The retrieved camera was sent to the manufacturer, but is now on its way back to Sable Island, where it will be relocated to a female seal during the first week of November. (Damian Lidgard / Department of Fisheries and Oceans / Ocean Tracking Network)

The camera was sent back to Australia, where the company downloaded data from its memory card.

“I didn’t really have much hope that there was going to be anything there, but I had a complete set of data,” Lidgard said, noting that there were 59 20-minute videos on the storage card.

Lidgard received the video a few weeks ago and is still going through it.

One of the high-resolution videos shows the cocks diving, feeding and chasing females on the surface in January 2018. Exxon’s Sable natural gas production platform is visible in the distance.

Did you know that seals sleep on the ocean floor?

The video is still being checked for one of the more notable behaviors revealed by other gray seal combs off Sable: sleeping on the ocean floor and rolling with the current.

The video provides insights not available from other sensors.

“The diving profile of a sleeping seal is like a U-shape,” Lidgard said. “The seal goes down to the bottom, spends time at the bottom and then comes up to the surface.

“Well, it’s a remarkably similar diving profile to a foraging seal. So without video, you can not tell if you see it as foraging, or if the seal is asleep. But now we can start with this video.”

He said an earlier video shows a seal sleeping for 16 minutes on the bottom of the ocean at a depth of 120 meters. The heart rate is lowered to a few beats per minute, a deep-sea nap at fishing spots that can be over 100 kilometers from Sable.

An unidentified crew member from Clearwater Seafood’s surf mussel ship Arctic Endurance delivers the lost camera to biologist Damian Lidgard, on the left. (Damian Lidgard / Department of Fisheries and Oceans / Ocean Tracking Network)

Lidgard said researchers previously interpreted behavior based on numbers from satellite transmitters and time-lapse recorders. They looked at how deep the seal dived and how long it dived.

“With the camcorder, I can sit at my desk and actually watch this animal out at sea, behave, dive deep, forage, hunt females,” he said. “I do not have to assume what the seal is doing.”

The camera will be attached to a female brand next month. When it returns to shore to give birth, the camera will be picked up.

“Less stress. Less anxiety,” Lidgard said.


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