Restoring a Quieter Ocean - Ocean Central

The consequences are profound. Many species rely on sound to navigate, feed, and reproduce, but chronic noise disrupts these behaviors, displaces animals from vital habitats, and in some cases triggers mass strandings. Whales, dolphins, fish, and even invertebrates are affected when ship noise overlaps with the frequencies they use to communicate.

The damage is economic as well as ecological. A European Maritime Safety Agency report estimates that cutting ship noise could avoid more than €100 million in environmental costs annually across the EU. Restoring a quieter ocean is essential to the long-term health of marine life, ecosystems, and coastal economies.

Sources of Ocean Noise

Noise from ships, offshore drilling, and other industrial activities affect marine life. The biggest source of underwater noise is global shipping, where a single cargo vessel can be louder than a jet engine at takeoff. Overlaying shipping lanes with whale migration routes reveals critical “blue corridors” where noise is most damaging.

“There are standardized underwater noise measurement protocols that can provide ship owners with a clear, comprehensive measurement of a ship's underwater noise emissions,” says Regan Nelson, Senior Oceans Advocate for the NRDC. “These represent the gold standard in measurement, but can be somewhat costly for ship owners.” 

When full compliance with protocols isn’t feasible, ship owners can still obtain useful data through opportunistic measurements, Ms. Nelson says. Certain ports, such as Vancouver, maintain underwater noise monitoring stations, and ships passing through generate data that is available to operators upon request (contact Transport Canada at [email protected]]. Similar measurement stations off North America’s coasts and the coast of Italy offer affordable ways to track vessel noise.

The Data Gap

While NOAA, ICES, and the International Quiet Ocean Experiment (IQOE) have begun mapping ocean soundscapes, monitoring remains patchy. Baseline data exist, but they are inconsistent across regions, making it difficult to measure cumulative impacts or evaluate the effectiveness of mitigation strategies.

The International Maritime Organization provides detailed technical guidance on assessing and managing underwater noise from individual ships, along with evidence on the impact of different measures. “There is plenty of guidance available,” says Ms. Nelson. The challenge is consistently applying these practices across fleets and regions.

One of the biggest obstacles is the lack of real-world, ship-specific data. “There is no consistent method for measuring noise, and most vessels are never tested under real operating conditions,” says Captain Anwar Farah, Vice President of Sustainability at Bahri. Operators also tend not to share key operational parameters such as speed, draft, engine load, and propeller condition, making benchmarking difficult across fleets, he says. 

Assessment is further limited by missing environmental context, including ambient noise levels and the sensitivity of marine species in the waters where vessels operate. Perhaps most significantly, Capt. Farah says, “There is no central database that tracks ship noise performance or records the effectiveness of different mitigation measures, making it hard to coordinate research or set realistic regulatory targets.”

The Impact of Reducing Noise

Reducing noise has immediate benefits for marine life. During the pandemic slowdown in 2020, whale communication ranges doubled compared with 2019, according to a report in Applied Ocean Sciences. Quieter ships are also often more fuel efficient, lowering operating costs for the industry and emissions. 

“Based on our industry assessment, summarised in Underwater Radiated Noise Guide, we find that a significant number of measures ships can apply to reduce energy demand and increase energy efficiency also help reduce underwater radiated noise,” says Chris Waddington, Technical Director at International Chamber of Shipping. “These actions therefore present a key opportunity to deliver against both climate and biodiversity goals in the maritime sector.”

Solutions Making a Difference

Reducing noise is a win-win for climate and biodiversity targets, and proven solutions exist. According to a 2025 EMSA report, mitigation measures could reduce underwater noise pollution by up to 70%. 

The most significant gains come from ship design and speed. Retrofits and propeller improvements can dramatically reduce noise and fuel use. By installing efficient propeller technologies and reconfiguring hull designs, Maersk’s “Radical Retrofit”, for example, cut ship noise by 75%. Yet Ms. Nelson says reducing underwater noise is rarely a design objective. Broader adoption of “Quiet Ship” notations could make it standard practice across the industry. 

Capt. Farah adds that quieter design often involves trade-offs. Measures that reduce cavitation or vibration can increase costs, affect fuel efficiency, or constrain hull and cargo configurations. Some energy-saving technologies, such as air lubrication systems, may even increase noise, reinforcing the need for careful, integrated design choices. 

Slowing down is another powerful lever. A 10% reduction in vessel speed can cut emissions by up to 40% while significantly lowering noise, according to a study published in Frontiers in Marine Science. Vancouver’s voluntary slowdown program showed just how effective this can be, lowering noise levels by 55% and reducing the risk of whale strikes at the same time. 

Other measures can complement these strategies, delivering immediate results for marine life, industry, and climate goals. For instance, seasonal noise restrictions in whale breeding grounds or biodiversity hotspots help minimize disruption when species are most vulnerable. 

The shift to cleaner fuels and advanced propulsion systems also dampens noise while lowering greenhouse gas emissions. “Addressing underwater radiated noise is about balancing three critical priorities: performance, efficiency, and environmental responsibility,” says Leonardo Leone Manzo, Sustainability Manager at E1 Series. “At E1, we view electrification as a catalyst to tackle both carbon and acoustic pollution simultaneously. By removing internal combustion engines and adopting electric propulsion, we can significantly reduce underwater noise emissions.” 

According to Capt. Farah, emerging innovations such as active noise control, vibration-damping materials, wind-assisted propulsion, and smarter RPM and speed-management systems are beginning to expand the toolkit for noise reduction, complementing inexpensive measures like propeller polishing and regular hull cleaning.

To scale these benefits across commercial, industrial, and recreational maritime transport, Mr. Manzo says the industry must align on innovation incentives that can achieve environmental footprint reduction while maintaining high levels of performance and output.

Signs of Changing Tides

Progress is taking place across the maritime sector to reduce underwater radiated noise. The International Maritime Organisation first issued voluntary guidelines in 2014 and issued revised guidelines in 2023, setting a clear roadmap for reducing underwater noise from shipping.

In the European Union, recent policy developments have introduced the first mandatory limits on underwater radiated noise. By 2024, Member States must integrate noise thresholds into national law under the Marine Strategy Framework Directive. These limits aim to ensure that no more than 20% of marine areas experience biologically harmful noise levels annually, focusing primarily on continuous noise from commercial shipping.

Internationally, the IMO has issued specific guidelines for the Arctic and Inuit Nunaat regions, emphasizing vessel speed reduction, monitoring, and engagement with Indigenous communities. Meanwhile, ports such as those in California and Vancouver are leading by example with voluntary ship speed reduction programs to lower underwater noise pollution,  also referencing the supporting services in URN measurement mentioned above.

Voluntary global initiatives are gathering momentum.

• The Global Partnership for Mitigation of Underwater Noise from Shipping, led by IMO, UNDP, and GEF, supports developing countries in implementing revised guidelines, building capacity, and adopting national toolkits. 
• The 2030 Shipping Pact for People and Nature, introduced at COP28, links shipping decarbonization with biodiversity protection, targeting up to a 50% cut in underwater noise while emphasizing justice, equity, and nature-based solutions. 
• The Sustainable Shipping Initiative’s Marine Biodiversity & Ocean Health Roadmap in turn, sets measurable goals, including a 3 dB reduction in noise per vessel transit. 
• The High Ambition Coalition for a Quiet Ocean, launched at the 2025 UN Ocean Conference, unites over 35 countries to advance science-based noise reduction solutions paving the way for increased momentum by mobilising national governments and regulators.

Together We Can Lower the Volume

Noise from shipping could double by 2030, according to WWF. To reverse course, every sector has a role to play:

• Industries: Adopt quieter technologies.
• Policymakers: Implement speed reduction initiatives.
• Governments: Invest in innovation and awareness campaigns.
• Ports: Incentivize quieter ships through fees and scheduling.

“Collaboration is critical in managing underwater radiated noise because no single ship or company can solve the problem in isolation,” says Capt. Farah. Ports play a key role through incentive programs and “just-in-time” arrival systems that allow ships to slow down safely. Regulators provide common baselines, and industry partnerships help validate technologies and share data—critical for avoiding fragmented or commercially unrewarded investments.

Wave is helping to accelerate this shift by building a global coalition of industry players to share best practices, consolidate feedback, and deliver on the targets of the 2030 Marine Biodiversity & Ocean Health Breakthrough and Roadmap.