Using two fiber-optic lines to track whales as they travel across the Arctic

The signals that are the foundation of modern communication are carried by fiber-optic cables, which run along the coasts of the continents and cross the oceans. While their principal work is broadcast communications, specialists have been investigating ways of utilizing this goliath organization to snoop on everything from tempests to tremors to whales.

For the past five hours, researchers have been able to estimate the positions and tracks of eight fin whales along a section of two nearly parallel fiber-optic telecommunications cables off the Norwegian arctic archipelago of Svalbard.

Martin Landr, head of the Center for Geophysical Forecasting at the Norwegian University of Science and Technology (NTNU) and one of the members of the team that carried out the work, stated, “This work demonstrates how we were able to simultaneously locate and follow these whales over an 1800 km2 area—with relatively low infrastructure investment.” He was also one of the members of the team that carried out the work.

“This work demonstrates how we were able to simultaneously locate and track these whales across an 1800 km2 area—while investing relatively little in infrastructure.”

Martin Landrø, head of the Center for Geophysical Forecasting at the Norwegian University of Science and Technology (NTNU) .

Changing fiber links into hydrophones
The framework the scientists utilized for this work is called appropriated acoustic detection, or DAS. DAS transforms the cables into a series of hydrophones by employing an instrument known as an interrogator to send laser pulses into a fiber-optic system and record the light pulses that return.

Landr and his associates initially started to investigate the capacity of DAS to keep submerged vibrations and sounds in the waters off Svalbard in June 2020, during the height of the coronavirus pandemic. They gathered approximately 250 terabytes of data and recordings over the course of 40 days at that time. From this information, analysts had the option to distinguish in excess of 800 whale tunes and calls.

Based on this early work, the analysts have grown their capacity to recognize different whale species and to lead continuous recording from the fiber optic links in Svalbard.

The researchers had access to two nearly parallel 250 km fiber-optic cables that run from Longyearbyen, the main settlement in Svalbard, to Ny-lesund, a research outpost in the northwest, for this most recent endeavor, which was published in Frontiers of Marine Science. The researchers were able to locate the whales in an area of approximately 1800 km2 with an accuracy of approximately 100 meters thanks to the paired cables.

Landr stated, “This demonstrates that the two fiber cables are an extremely effective means of monitoring whales in the Arctic.”

A dissolving icy
As a Norwegian domain in the high ice, Svalbard offers Landr and different specialists a significant base from which to concentrate on this evolving biological system.

This graphic depicts how researchers were able to use fiber-optic cables to simultaneously track multiple whales in the Arctic, off the coast of Svalbard. The maps show an overview of a 60-kilometer stretch of cables and the positions and tracks of up to eight acoustically detected whales over a 5.1-hour period, color-coded from dark to light. Credit: Frontiers in Marine Science (2023). DOI: 10.3389/fmars.2023.1130898

Recent research suggests that the Arctic could be ice-free in the summer as early as 2035. This would likely lead to an increase in the number of shipping and cruise ship trips around the world.

For instance, Visit Svalbard estimates that as many as 35 cruise ships and additional smaller expedition ships will transport up to 75,000 people to Longyearbyen and the surrounding area in 2023.

Could lessen the likelihood of a ship striking a whale.

Some research indicates that fin whales have begun spending all year in the Arctic. This suggests that whales are already changing how they use the Arctic and Antarctic as feeding grounds. This indicates that an increase in ship traffic in these regions may also raise the probability of ship strikes. The researchers stated that making use of the existing network of fiber-optic cables and DAS could assist in reducing this possibility.

The researchers wrote, “The capabilities shown here establish the potential for a near-real-time whale tracking capability that could be applied anywhere in the world where there are whales and fiber-optic cables.” Using a similar strategy, a real-time collision avoidance system could be developed in conjunction with ship detection to reduce ship strikes.”

More information: Robin André Rørstadbotnen et al, Simultaneous tracking of multiple whales using two fiber-optic cables in the Arctic, Frontiers in Marine Science (2023). DOI: 10.3389/fmars.2023.1130898

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