Every day, our lives are filled with sounds: birds chirping in the morning, cars honking down the highway, people chattering in a crowded cafe. Most of the time, we don’t even notice these noises because they fade into the background. But when someone suddenly screams in your ear, the noise becomes painful and impossible to ignore. That’s what many underwater animals are going through today. Sounds in the ocean used to be calm and natural, but now they’re becoming louder and more harmful. Underwater noise pollution has become one of the most alarming yet overlooked threats facing ocean life.
Over the past few decades, human-made noise has increased drastically in our oceans. Research shows that it stresses out marine animals, disrupts behavior, and can even physically harm them. Because I care deeply about marine life, I decided to research more to understand how this noise affects animals underwater. What I found was both unexpected and shocking.
The majority of harmful underwater noise comes from large shipping boats. When ships move across the ocean, their propellers create bubbles that rapidly form and collapse This process is called cavitation. Each collapsing bubble results in a sharp burst of sound, like popping hundreds of balloons underwater. These sounds are not only loud but can travel long distances making them a severe and wide stretching threat.
Despite the magnitude of the problem, modern propellers remain largely unchanged because they are efficient, low in cost, and most importantly, the issue of noise pollution is not widely known. But the consequences of not taking action extend far beyond just “annoying” marine animals. Underwater noise directly interferes with animal health, behavior, and reproduction.
One of the biggest impacts is on communication. Many marine species rely heavily on sound to survive as light penetrates only a few hundred feet underwater. The most prominent use of their advanced hearing is to find mates. In The Role of Acoustic Signals in Fish Reproduction, M. Clara P. Amorim (2023) shows that male fish produce certain sounds that tell females about their size, condition, and readiness to mate. In species like the painted goby, females had a higher success rate of reproduction with males that called out more frequently. But when background noise increases, their calls are drowned out and females become less likely to spawn. This means noise pollution can directly reduce reproductive success. [1]
The OceanCare report by L. Weilgart (2018) builds off this concern. After reviewing 115 studies on fish and invertebrates, the report concludes that loud noise can damage several physical aspects such as the inner ear, the lateral line, and the swim bladder. Severe and constant noise exposure can even cause brain damage and can bend the spines of young fish. In some regions, fish catches have dropped by 80% due to noise pollution causing population decline. [2]
The problem of cavitation and noise pollution not only harms fish, but also marine mammals, especially whales. A study modeling baleen whale migration in the North Sea shows that increased noise is severely harmful. Cargo ships take the same general routes of whale migration paths to ship goods, so when it comes time for migration the whales find themselves swimming down a path of constant and loud noise. Because of this they are unable to communicate clearly and forced to change their migratory paths in order to avoid the painful noise. This change causes them to waste energy and time. [3] In a warming world where whales already struggle to survive, noise pollution adds yet another obstacle.
So, what can we do?
The article “Seeking Tranquil Waters” (Hanwha, 2023) highlights several promising solutions. Air lubrication systems can reduce noise by coating the hull in a layer of bubbles. Advanced propellers designed to reduce cavitation can significantly lower noise. The PRAIRIE system proposes a model that injects air directly through the propeller blade to soften cavitation bursts. However, none of these solutions have been researched thoroughly and universally. Further applying these findings is held back by cost and lack of awareness. [4]
Still, the ocean is too important to ignore. It generates trillions of dollars in economic value, regulates the climate, and supports millions of species. If we keep adding noise without doing anything about it, marine animals will continue to struggle to survive.
We can’t undo the damage that has already happened, but we can prevent things from getting worse. Raising awareness, supporting quieter ship technology, and encouraging stronger environmental rules can all make a difference.
What we do matters. And underwater noise pollution is no longer silent, it is calling out for action.
