The impacts of noise pollution on marine fauna are often sub-lethal, yet far from harmless. Over time, they can compromise health, alter behavior, and reduce survival at both individual and population levels, ultimately affecting the functioning of marine ecosystems. 

One of the most common effects is auditory masking. Imagine trying to talk to a friend in a crowded room: the background noise drowns out the words, and you struggle to understand each other. The same phenomenon happens underwater. Maritime noise pollution can interfere with the detection of acoustic signals animals use to communicate, find mates, navigate, detect prey, or avoid obstacles.
This issue is particularly critical for mysticetes (baleen whales), whose low-frequency calls overlap with commercial shipping noise. Many species attempt to compensate for noise by “speaking louder,” increasing the intensity or shifting the frequency of their own calls. However, these changes can be costly. 

Noise pollution can also drive marine animals away from important feeding or breeding grounds, force them to alter their migratory routes, and change their swimming and diving patterns. Chronic exposure to low-level noise can trigger physiological stress responses, weaken the immune system, and reduce reproductive success.

Very loud man-made noises, such as those from air guns used in seismic surveys, can cause physical damage, and even death. Beyond fish and mammals, invertebrates like cephalopods and jellyfish have shown signs of acoustic trauma and damage to their statocysts (balance organs) following exposure to high-intensity sounds. Furthermore, shockwaves from air guns can drastically reduce zooplankton abundance up to 1 km from the source, with potential cascading effects throughout the food web.

High-intensity sounds, such as those from military sonar, have been linked to mass strandings of cetaceans, particularly beaked whales. The loud noise coming from military sonar disrupts normal diving behavior, causing animals to rise too quickly to the surface, leading to decompression sickness and skin damage from gas bubble lesions.

Despite making up less than 1% of the Earth’s ocean surface, the Mediterranean Sea is home to about 7% of global marine biodiversity and hosts around 20% of global maritime trade. This high traffic density, combined with the sea’s semi-enclosed nature, makes the Mediterranean particularly vulnerable to underwater noise pollution. 

Major shipping routes overlap with ecologically critical areas. A notable example is the Pelagos Sanctuary in the northwestern Mediterranean, where cargo ships and ferries intersect with habitats used by species which are highly sensitive to anthropogenic noise, such as fin whales, beaked whales, and sperm whales.

The northern Adriatic is another critical area: shallow, heavily trafficked, and bordered by densely populated coastlines, it experiences high levels of background noise from maritime and port activities, significantly affecting marine life.
The Sicily Channel, crossed by commercial vessels, tankers, ferries, and fishing vessels, serves as a vital corridor for many cetacean species, including fin whales, bottlenose dolphins, striped dolphins, and beaked whales, making it highly vulnerable to acoustic pollution.

Unlike chemical pollutants that can persist for decades, noise stops as soon as its source is turned off. This offers a unique opportunity for prompt and effective action. 

Measures such as slow steaming, designing quieter propellers, and rerouting commercial traffic away from sensitive habitats can mitigate the impacts of underwater noise pollution.
Additional solutions include the use of bubble curtains during offshore construction and more strategic marine spatial planning. Together, these actions can help restore the Ocean’s natural soundscape.

Marine Protected Areas (MPAs) are increasingly recognized as essential tools for safeguarding acoustic quality. 
By regulating vessel traffic, restricting navigation in specific zones, enforcing speed limits, and limiting sonar and hydrojet use, MPAs can act as acoustic havens. 
Since sound travels much farther and faster in water than in air, the noise generated in one location can affect marine life far away. The next challenge will be creating protected acoustic corridors connecting MPAs, ensuring safe and quieter routes for marine species.

Recognizing the importance of sound for marine life is the first step toward reshaping our relationship with the Ocean: protecting it also means listening and choosing to make less noise.