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

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 oil, fuel, or debris—can persist long after the initial event, spreading across both surface and seabed ecosystems.

Bartholomew warns that even a single major spill could have far-reaching consequences: “A major oil spill in the Strait of Hormuz could contaminate beaches and severely affect turtle nesting sites, including islands such as the Sir Bu Nair.”

“Oil spills can kill adult turtles and sea snakes and damage nesting habitats. They could also harm marine mammals such as the Indo-Pacific humpback dolphins in Musandam waters [near the strait] and the Indo-Pacific bottlenose dolphins, as well as kill seabirds.”

The danger is not limited to the surface. Whale sharks that migrate seasonally into the Gulf through the Strait of Hormuz, particularly between May and September, are vulnerable to floating oil because they feed near the surface.

Bartholomew adds: “Although oil generally floats, storms and high waves can mix it to deeper depths, which could negatively affect coral in the strait’s region, where coral diversity is the highest in the Gulf, especially on the Iranian side.”

Surface pollution can also alter animal behavior in unexpected ways. Oil slicks create shaded areas on the water’s surface, similar to fish-aggregating devices, which naturally attract small fish. This can draw other animals—including turtles, sharks, and marine birds—into contaminated zones, exposing them to toxins and increasing the risk of ingestion or coating.