How to build a ringed seal bark detector, step two
Once Karlee had a good supply of annotated seal barks, she had to connect with the right kind of artificial intelligence. She needed an interface, a place to develop and train an AI detector. For that, she relied on the work of the MERIDIAN Data Analytics Team at the Institute for Big Data Analytics at Dalhousie University.
The MERIDIAN team developed an interface called Ketos. (It’s named after the ancient Greek word for whale.) MERIDIAN made Ketos specifically for researchers working with underwater acoustics.
A researcher like Karlee can enter 196 hours of seal barks in Ketos. Ketos becomes a base on which she can build and train a detector. And Ketos is free to use!
Ketos provides some of the software needed to handle acoustic data. Karlee still needed to “write the script” for her detector. (For those interested in coding, she used Python as the programming language.)
Once the detector had been trained on annotated data, Karlee set it loose on “raw” acoustic data, to see how well it did.
“It still picked up false positives,” she says. “Any short sound that looks like a vertical bar on the spectrogram can be mistaken for a ringed seal bark. If the rope fastening the hydrophone hits the side of the hydrophone, it can register as a false positive. The detector can get confused by bubbles and boats, too.”
Karlee went through the new data manually. She corrected the detector’s mistakes, then she retrained it on the corrected data. “With more data, the detector will become more accurate,” says Karlee. “The more it is trained, the more accurate and helpful it becomes.”
Karlee is now making an easy-to-use interface for the completed detector. She and Dr. Halliday will offer it, free of charge, to any researcher with acoustic data from the Arctic Ocean.
“Other researchers use PAM to record data for other species,” explains Dr. Halliday. “With a detector, they can afford to check their recordings for ringed seals.”
The ringed seal: a species on thin ice
“Ringed seals are understudied,” says Dr. Halliday. “They’re a species of special concern because they rely on the Arctic ice and that ice is changing rapidly.”
“We now have years of underwater acoustic recordings of the Arctic Ocean. Biologists can learn more about ringed seals by observing changes in where and when ringed seal sounds appear on the recordings.”
Just how does a ringed seal bark underwater without running out of breath?
“The seal vibrates air up and down its windpipe,” explains Dr. Halliday. The air stays in the seal’s body, so the seal has enough breath to stay under water – typically for 5-10 minutes for a normal dive. Then it comes up through the ice to breathe. Ringed seals use the claws on their fore-flippers to keep air holes open – in 2-metre-thick Arctic ice!
Ringed seals play a central role in the Arctic food chain. They dive to catch fish, shrimp, and small crustaceans. In turn, polar bears eat ringed seals.
“They are the favourite food of polar bears,” says Dr. Halliday. “If ringed seals disappear, it has implications for all the wildlife in the Arctic ecosystem. Ringed seals are also culturally important, part of the Inuit cultural identity.” Inuit living in the region rely on ringed seals for food and clothing.
But because ringed seals live, hunt, and raise their pups on and under the Arctic ice, they are facing a huge threat because of climate change. The Arctic is warming up to four times as fast as the rest of the world. Climate change means more than vanishing ice. Ship traffic in the Arctic increases as the ice retreats. WCS Canada’s research is trying to shed light on how ship noise can negatively affect mammals such as ringed seals.
What management practices can help ringed seals survive and thrive? What will reduce stress on this species? What choices lead to a world where ringed seals continue to delight and nourish us for generations to come?
We don’t know today. But by using AI to speed up the learning process, Karlee, Dr. Halliday, and the Arctic Acoustics Initiative team have brought us closer to the answers.
