Fin whales are the second largest mammals on the planet. The development of a new technology that allows researchers to eavesdrop on the animals as they swim in the Arctic could one day help prevent ship strikes.
This graphic show how researchers were able to simultaneously tracking multiple whales using fiber-optic cables in the Arctic, off the coast of Svalbard. The maps shows an overview of a 60 km long section of the cables, showing the positions and tracks of up to eight acoustically-detected whales, colour-coded from dark to light over a 5.1-hour period.
Newswise — Fiber-optic cords edge the shores of the landmasses and weave through the seas, transporting signals that constitute the foundation of communication in the present era. Even though their principal function is telecommunications, scientists have been investigating methods to exploit this immense infrastructure to surreptitiously listen in on phenomena ranging from tempests to seismic events to cetaceans.
Working with twin, almost parallel fiber-optic telecommunication cords off Svalbard, an arctic archipelago in Norway, scientists have managed to assess the locations and movements of eight fin whales along a portion of the cable - over a period of five hours.
Martin Landrø, who leads the Centre for Geophysical Forecasting at the Norwegian University of Science and Technology (NTNU) and is part of the research team, stated, "This research showcases how we managed to detect and monitor these whales across an 1800 km2 region, with comparatively modest infrastructure investment."
Transforming fibre cables into hydrophones
The method employed by the scientists in this study is known as Distributed Acoustic Sensing (DAS). DAS utilizes an apparatus called an "interrogator" to transmit laser pulses through a fiber-optic network and record the reflected light pulses, essentially transforming the cables into a set of hydrophones.
Landrø and his team initially began examining DAS's capability to capture underwater vibrations and sounds in the vicinity of Svalbard in June 2020, during the peak of the Covid-19 pandemic. During this period, they obtained 40 days of recordings, amounting to roughly 250 terabytes of data. Using this data, the researchers detected over 800 whale songs and vocalizations.
Building on this initial research, the team has broadened their capacity to distinguish between various whale species and to conduct live recordings from the fiber-optic cables in Svalbard.
In their latest study, published in Frontiers of Marine Science, the researchers had access to two almost parallel fiber-optic cables that are 250 km long and stretch from Longyearbyen, the principal settlement in Svalbard, to Ny-Ålesund, a research outpost located to the northwest. The paired cables permitted the team to pinpoint the whales with an accuracy of about 100 meters, within an expanse of roughly 1800 km2.
“This shows that the two fibre cables are a very effective means of monitoring whales in the Arctic,” Landrø said.
A melting Arctic
Svalbard, being a Norwegian territory situated in the high Arctic, provides Landrø and other researchers a crucial center from which to investigate this transforming ecosystem.
Current research forecasts that the Arctic could become devoid of ice during the summer as soon as 2035, which could intensify shipping and cruise ship traffic across the northernmost part of the planet.
To illustrate, Visit Svalbard reports that as many as 35 cruise ships and supplementary smaller expedition vessels are anticipated to ferry up to 75,000 individuals to Longyearbyen and the surrounding areas in 2023.
Could reduce ship strike risk
Whales are already altering their patterns of utilizing the Arctic and Antarctic as feeding grounds, with certain studies indicating that fin whales are now spending more time in Arctic areas throughout the year. Consequently, heightened shipping activity in these regions can also raise the chance of collisions with ships. According to the researchers, the use of the existing fiber-optic cable network and DAS technology could help decrease this likelihood.
"The demonstrated capabilities establish the possibility of a near-real-time system for tracking whales, which could be utilized anywhere in the world where there are fiber-optic cables and whales," the researchers wrote. "When paired with ship detection utilizing a similar approach, a collision avoidance system could be established in real-time to minimize the risk of ship strikes."
This advancement coincides with the time when NORDUnet, the Nordic Gateway for Research and Innovation, and the Nordic NRENs have initiated several efforts to explore and prepare for the first submarine fiber-optic cable network connecting Europe, Asia, and North America, ensuring a shorter route through the Arctic Ocean. The endeavor is dubbed Polar Connect.
If such an initiative is realized, “it would open far greater areas for us to follow whale movements in the Arctic,” Landrø said.
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Credit: NOAA Fisheries
Caption: Fin whales are the second largest mammals on the planet. The development of a new technology that allows researchers to eavesdrop on the animals as they swim in the Arctic could one day help prevent ship strikes.
Credit: Graphic: Røstadbothnen et al. 2023. Front. Mar. Sci. 10:1130898.
Caption: This graphic show how researchers were able to simultaneously tracking multiple whales using fiber-optic cables in the Arctic, off the coast of Svalbard. The maps shows an overview of a 60 km long section of the cables, showing the positions and tracks of up to eight acoustically-detected whales, colour-coded from dark to light over a 5.1-hour period.
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