Navigating the Technical and Biological Hurdles of the Future’s Quieter Oceans

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Future directions for quieter vessel operations

Two key challenges remain for those developing models and other systems to enable real-time noise monitoring or adaptive operational changes.

The first relates to information about the nature of noise that different vessels emit. Particularly for large commercial vessels, specific design details combined with operating parameters mean that every vessel is a unique system with a unique noise footprint. Two similarly designed propellers may produce different noise emissions, depending on the vessel’s hull configuration as well as the age and maintenance status of the propeller. Moreover, noise emissions from different components, as well as from a vessel as a whole, may vary over the course of its operations as it moves through different oceanographic conditions and operational demands. For example, a tug that is towing has a very different noise profile than a tug simply transiting.

Currently, long-term, real-world (at sea) data is not yet readily available. This lack of data comes down to three main factors. First, concerns about vessel noise impacts on marine life are relatively recent. As such, there wasn’t a widespread move to collect data until quite recently. Second, ship design details are usually proprietary and cannot be included in detailed models. This means that underwater noise data from different ships needs to be recorded for analysis. Finally, equipping vessels with vibration sensors and data loggers comes with a time and financial cost to ship operators, making widespread data collection challenging.

To address these gaps, further efforts are needed to reduce barriers and enable the integration of design details and real-time noise information into models that support real-time operational guidance. Although safety and navigational constraints may limit noise-reducing operational changes for large vessels, smaller and more manoeuvrable vessels may offer more practical opportunities. Additional research is needed to determine how such operational changes can be implemented safely while still reducing noise.

Most existing underwater-noise data comes from large vessels, even though they are not the only contributors to the underwater soundscape. Collecting real-world underwater noise data from small vessels, as well as assessments on the performance and noise-reduction potential of different operational changes for these vessels, is crucial for understanding and addressing their underwater noise impacts.

The second challenge relates to our knowledge of the impacts of noise on marine life. There are still many unknowns about how and when noise begins to cause harm, particularly for non-mammal marine life like fish and invertebrates. Understanding where and when noise reduction is most needed could help guide operational change recommendations. For example, operational changes could be particularly critical in busy waterways where the volume of vessel traffic creates a continuously noisy environment, or during breeding seasons or at specific times of day or year when noise-sensitive marine animals are more active. Equally, understanding the distances at which marine animals start changing behaviour or suffer other harms could help guide operational change recommendations for when and where they will have the greatest benefit.

Nevertheless, it is important to consider the potential unintended consequences of operational changes. For example, a vessel that slows down to reduce noise near a pod of killer whales may later increase speed to recover lost time, resulting in equal or even greater total noise over the full voyage. While such measures may benefit the animals immediately nearby, they could inadvertently increase impacts on other marine life. Continuing research into the effects of underwater noise on marine ecosystems will help clarify where and when operational changes offer the greatest benefit. Looking ahead, research and development focused on operational strategies—such as specific manoeuvres, speed adjustments, routing choices, and towing conditions—will be essential for identifying safe, practical, and effective approaches to noise reduction across different vessel types. Demonstration projects will be particularly valuable for evaluating these measures in real-world settings, especially for smaller and more manoeuvrable vessels where operational adjustments may be most feasible and where current data remains limited.

This article was prepared by Clear Seas on behalf of Transport Canada as part of the Quiet Vessel Initiative and is part of a four-article series on operational changes to limit underwater vessel noise.

Continue learning about the new discoveries and challenges in making vessels quieter with the other topics in this series here

The Quiet Vessel Initiative is a federally funded program through Transport Canada. Industry partners and researchers interested in potential research and development collaborations to advance innovative solutions in marine technology are invited to contact the Quiet Vessel Initiative team at Marine-RDD-maritime@tc.gc.ca.