Dalhousie's Ocean Tracking Network is on a mission to find out where fish in the waters surrounding the Maritimes go, and why.
The OTN deployed the robot, called a Wave Glider and made by Liquid Robotics, equipped with a sensitive acoustic receiver in the Gulf northwest of Stephenville, N.L on June 19. The glider spent nearly two months at sea and travelled more than 3,000 kilometres.
Acoustic tags, small sound-emitting devices, were mounted on salmon that were released earlier this year from various rivers along the New Brunswick and the Quebec coast, enabling researchers to track their migration.
While the fish are known to leave the Gulf of St. Lawrence primarily through the Strait of Belle Isle, between Newfoundland and Quebec, the route they take to get there is unknown.
More than a high-tech surfboard
The glider looks like a high-tech surfboard. The autonomous robot, or drone, has two components, a surface component and an undersea component.
The surface component includes a solar panel, batteries and computer storage capable of storing up to six terabytes of data.
The undersea component has a series of wings that use the motion of ocean waves to propel the drone forward at an average speed of about 1.5 knots.
The receiver is able to detect tagged fish that are within 400 to 800 metres of the glider, and the information is relayed via satellite to an onshore operations centre.
Eben Franks, senior sales manager for Liquid Robotics, says the drone can stay out on a mission for at least a year. In fact, their device currently holds the record of the longest distances and duration of continuous ocean voyages of any autonomous platform in the world.
"A couple of square feet of solar panels provide all the electrical power for the instrumentation and communications," said Franks.
"It has a set of wings that flop up and down and provide up to 300 pounds of forward thrust."
Project is a first
Richard Davis, Dalhousie OTN's group lead technician, said this project is a first.
"We have never done anything like this before, so if we got any hits at all, it was a success and we got hits on several kinds of fish," said Davis.
"The original mission was to see if we could pick up some tagged salmon released from the Miramichi River and the Restigouche River and some other rivers in New Brunswick."
Understanding where salmon go and when they leave the rivers is important for researchers and fisheries officers to better manage the declining species.
"We have also been picking up some tagged cod and also some fish we don't know what they are and we are hoping to find out," said Davis.
The same technology OTN scientists are using to track fish in the Atlantic Ocean is currently being used to track great white sharks in the Pacific Ocean and was recently featured on Discovery Channel's Shark Week.