Researchers have launched a seafloor-based monitoring network in Quebec's lower St. Lawrence River to track seismic activity and marine life. The system, positioned between Rimouski and Sept-Îles, provides continuous data on whale vocalizations, shipping noise, and tidal patterns.
Twice the seismic data in the Bas-Saint-Laurent region
The new network, a collaboration between McGill University, Natural Resources Canada, Université du Québec à Montréal, and Dalhousie University , is significantly outperforming traditional methods. As reported in the recent study, the seafloor-based system identified twice as many earthquakes as the conventional National Earthquake Monitoring System. This increased sensitivity stems from placing seismometers directly on the riverbed, allowing them to capture even the slightest vibrations.
Beyond geological events, the technology used by researchers from McGill University and Dalhousie University captures a wide spectrum of underwater phenomena. yajing Liu from McGill’s Department of Earth and Planetary Sciences noted that these seismometers can detect acoustic waves from whales that disturb the sea floor. this allows for a holistic view of the water column and seabed, providing data that was previously difficult to aggregate in such a wide area.
The acoustic overlap between shipping lanes and whale habiitats
The St. Lawrence estuary serves as both a high-activity seismic zone and a major corridor for maritime traffic. This dual role creates a significant environmental challenge: the noise from large vessels may interfere with the communication of marine mammals. According to the report, researchers are currently compiling two distinct catalogues—one for whale songs and another for noise generated by riverine transport—to measure how much these signals overlap.
This overlap is not just a theoretical concern.. Initial analysis of a single day's data showed that whale songs and maritime traffic were occurring simultaneously in the same location. this finding underscores the urgency of understanding how anthropogenic noise impacts cetacean communication, particularly when ship noise reaches decibels that drown out biological signals.
Closing the 100-kilometer gap left by land-based stations
Previously, researchers relied on land-based seismometers along the coast to monitor the estuary. However, these terrestrial stations had a major limitation:they could only detect whales that were swimming very close to the shore. Because the St. Lawrence estuary can reach widths of up to 100 kilometers, a vast portion of the river's activity remained a "geographical blind spot."
The new seabed system overcomes this distance issue by providing continuous monitoring across the entire width of the waterway. By capturing signals from the middle of the river, the network offers a more complete acoustic picture. This data also improves ocean circulation models by providing constraints from the ocean floor , which is vital since whales rely on these circulation patterns for their nutrient supply.
What the long-term impact of mining blasts and tides will reveal
While the system has already proven its worth, several questions remain regarding the full scope of the data collected between September 2023 and May 2025. The sensors record 250 data points every second, creating a massive volume of information that includes unexpected signals like mining blasts and tidal fluctuations.
It remains to be seen how these specific anthropogenic disturbances, such as mining, will be integrated into future environmental regulations. Furthermore, while the system provides better constraints for ocean current models, the exact degree to which this data will change how we predict nutrient availability for whales is still being analyzed. The researchers have yet to release the final conclusions on how these combined factors will reshape the management of the Gulf of St. Lawrence.
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