Canada’s first and only scientific Wave Glider completed its mission remotely uploading fish-migration data from 184 fixed, underwater receivers. The receivers are part of a 205 km animal tracking-array used by Canadian scientists to track the movements of sharks, seals, tuna, salmon, eels and other fish or marine mammals carrying acoustic tags.
It doesn’t look like the stealthy science-fiction drones of Hollywood as it bobs along the surface (it glides smoothly on a calm day), but this bright yellow surfboard packs major scientific punch at low-cost and low-risk.
Receivers detect and store individual animals’ tag ID as well as dates/times of the detections. This data gives researchers a look into the animals’ behavior and survival over time. Technicians must go out on boats and manually offload data from the bottom-mounted receivers. That is, until now.
Duncan Bates is the technical lead for the Halifax-based Ocean Tracking Network (OTN). He takes most of December off to go lobster fishing and spend with his family. His vacation started a little earlier when news that the Wave Glider nearing the end of its mission meant he didn’t have to go to sea in November.
“It can be a bit rough this time of year; we wait for a good weather window to open up then we go and do the offload until either it’s completed or we run into bad seas. Sometimes we’ve had to go out on two or three separate trips to get all the data,” says Bates.
The glider, built by U.S. company, Liquid Robotics Inc., uses vertical wave-motion to flip “wings” on an underwater sled, driving it forward as it travels up and down. The wave-induced movement thrusts the glider along a preprogrammed path in the ocean. Completely self-propelled, the glider doesn’t use any fuel. Solar panels power navigation and communications systems as well as the science-bay, which records data from various oceanographic instruments.
The real advantage comes from the acoustic modem mounted on the underwater sled. The modem offloads data from the underwater receivers to the glider’s science-bay without the need to bring the receivers to the surface.
“It acts just like an underwater telephone; it calls the receivers and says, ‘hey, tell me about the fish you saw’,” says Richard Davis, head of the glider group for OTN. “We’ve modified this thing to do our work for us with amazing results.”
Bates and his team spend a week or more at sea offloading data from the receivers on the ocean floor. Ship-time needed to maintain this and similar receiver arrays run almost $10,000 a trip. However, piloting the Wave Glider only costs $150 per day, and though the glider took longer to offload the array, that’s nearly a third of the cost to collect the data.
Sara Iverson, Scientific Director of the OTN says, “The capacity this thing has to revolutionize the way we’re doing research in Canada and around the world is phenomenal; the contributions Canada has made to global ocean-science in the last decade are tremendously important and we can continue to be world-leaders in science and technology as long as we keep pushing the envelope.”
This capacity to offload data remotely is a major proof-of-concept success for the ocean-science community. Widespread use of the glider could free up research budgets to purchase more tags, hire specialized staff and expand operations to critical or unexplored areas. Perhaps most importantly, it markedly reduces the safety risk to personnel who are on the front lines of research being conducted in the Arctic, in the northwest Atlantic, and other areas that pose high risk.
“It’s a lot of work to keep up with equipment prep, knowing that we have to go at any time, as soon as the weather’s good,” says Bates. “It’s hard on my kids to be away so often, but maybe that’ll change.”
For more information, visit oceantrackingnetwork.org/return-of-the-intrepid-wave-glider.
