Located 300 kilometres southeast of Nova Scotia and surrounded by the choppy waters of the North Atlantic lies Sable Island — a sliver of iconic Canadian landscape formed entirely of sand. Considered unique for both its uncommon geography and ecosystem, the island teems year-round with birds, wild horses and the world’s largest grey seal breeding colony.
Every year since 2009, a small team of dedicated scientists from Fisheries and Oceans and Ocean Tracking Network, have made their way to the island with one goal: to document seals’ migrations, distributions, reproduction, and feeding patterns using electronic tracking tags. The seal project is part of a larger OTN ‘bioprobe’ project, which uses larger marine animals to collect oceanographic and biological data by outfitting them with tracking technology for short periods of time.
This September, the team tagged an adult female seal nicknamed Emma. The team doesn’t usually name the animals they track, but this trip was a little different; Emma was deployed with a video camera to record her behaviour while she is out at sea feeding.
In doing so, the team can view her behaviour and better understand where, when and how these remarkable marine animals catch their prey. The team will track Emma’s movements using a GPS tag until her eventual return to the island in December, when she will give birth to her pup.
OTN will be sharing Emma’s tracks on a weekly basis – Tweeters can follow @OceanTracking or search #EmmaTheSeal or Ocean Tracking Network on Twitter or Facebook for updates. Stay tuned to find out where she goes!
A grey seal outfitted with tracking equipment swims in the waters off Sable Island. Photo: Damian Lidgard
While a camera provides unprecedented underwater footage, like any piece of technology it’s limited by its battery life. To preserve power, the camera is programmed to turn on when Emma is most likely foraging– at night and below depths of 25m.
To allow the researchers to see what Emma is doing when there is little natural light, the camera is equipped with infra-red lights that will illuminate the fish Emma may feed upon. The camera also has solar panels that will recharge the batteries when Emma returns to Sable Island to rest in between her trips to sea.
Emma’s head and body movements will also be tracked using an accelerometre tag, an activity tracker similar to a fitbit. This small tag, attached to the seal’s head and back, will record fine movements of the seal while she performs behaviours such as diving, travelling, resting and feeding. Each of these behaviours will produce a characteristic signal in the accelerometre data stream, and that signal can be linked to each behaviour by using the video footage recorded by the camera. This means that in future years, the team can deploy accelerometres without a camera, but rather understand movements from accelerometre data.