Marine Animals in the Strait of Hormuz Don’t Get a Ceasefire | WIRED

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Beneath the surface of the Strait of Hormuz and the surrounding Gulf lies a biological sanctuary. The region is home to around 7,000 dugongs and fewer than 100 Arabian humpback whales—a nonmigratory population that cannot leave these waters.

The United States and Iran last week agreed to a two-week ceasefire, following weeks of escalating tensions that disrupted shipping through the Strait of Hormuz.

But the ceasefire has not cleared the water. Naval mines, residual military activity, and congested shipping lanes mean the strait remains a high-risk environment—not just for vessels but also for the ecosystems beneath them.

With 800 vessels currently trapped behind a monthlong maritime blockade, shipowners are preparing to move. But while headlines focus on oil and trade, a different kind of resident is struggling to navigate the Arabian Gulf.

These species are extremophiles, adapted to heat and salinity levels that mirror what much of the world’s oceans may face by 2050. Scientists see them as a living blueprint for how marine ecosystems might survive climate change—if they survive this moment.

Sound Is Survival

Underwater explosions and military sonar don’t just scare whales, they can physically blind them, leading to stranding and death. The Arabian humpback whale, unlike its cousins in the Atlantic, does not migrate. For them, the Gulf is not a corridor but home, a permanent habitat.

Olivier Adam, a researcher at Sorbonne University Abu Dhabi, says that the Gulf’s resident cetaceans—better known as marine mammals—have limited options: Either abandon their habitat or remain and endure prolonged exposure to noise.

In the case of Arabian humpback whales, relocation is not realistic, as they are one of the only populations that do not migrate between feeding and breeding areas. “These baleen whales have no way to escape,” he says.

Photograph: Getty Images

The sounds they endure are more than just a nuisance. They are a physical and social barrier. Whales rely on sound for nearly every essential function: feeding, navigation, reproduction, and social interaction. When that acoustic environment is disrupted, the effects are immediate. “Their emitted sounds, which are therefore important for structuring their social groups, can be masked by underwater noise pollution from human activities at sea,” Adam says.

Humpback whales communicate in low-frequency sound—meaning the same range filled by ship engines and sonar—making them especially vulnerable to disruption.

Adam explains that underwater noise from maritime traffic interferes with feeding behavior and can have physiological effects on the auditory system. “The radiated underwater noise generated by maritime traffic disrupts the feeding of humpback whales.”

As noise levels rise, whales reduce their diving activity—effectively entering a forced fasting period that weakens them over time.

From Disruption to Damage

In the narrow, 21-mile-wide funnel of the strait, military activity introduces shock waves and pressure changes that marine species are not built to withstand. Underwater explosions can be strong enough to kill fish outright and damage the auditory systems of larger marine mammals.

Aaron Bartholomew, professor of biology, chemistry, and environmental sciences at the American University of Sharjah, suggests that “while whales and dolphins may temporarily move out of areas where there is significant naval sonar activity,” the intensity of modern maritime conflict poses lethal risks.

Adam warns that the impact can be lasting: “These explosions can also damage the auditory system of cetaceans, which may temporarily or permanently lose their hearing.” Even when not immediately fatal, the effects can weaken animals over time and disrupt their ability to survive in already stressed conditions.

Naval mines introduce similar risks even before detonation. When triggered, they generate high-pressure shock waves that can rupture internal organs in fish and damage the auditory systems of marine mammals.

Bartholomew says that while some species may attempt to move away from high-activity zones, that displacement comes at a cost. “Whales and dolphins may temporarily move out of areas where there is significant naval sonar activity. Their short-term behavior in the region may be negatively affected," he says. "Overall, they will likely be fine. The most likely outcome is temporary displacement from areas with extensive sonar use.”

In a confined corridor like the strait, even temporary displacement can interfere with feeding patterns and habitat use, turning short-term disruption into longer-term ecological stress.

“Slow-Flush” Nature

The Arabian Gulf is uniquely vulnerable, because it does not easily reset.

It is what scientists describe as a “slow-flush” sea, taking between two and five years to fully exchange its waters. That means contaminants—whether from o