Chile records the world’s highest whale mortality caused by ship strikes. A study published in the journal Marine Policy this year found that over the past decade Chile averaged five whale deaths a year due to ship collisions. Sri Lanka and the US west coast followed with between three and four killed annually, based on necropsies of dead beached whales.

Researchers estimate these numbers are the tip of the iceberg, accounting for approximately 10% of the total deaths. Most struck whales sink or float out to sea, and carcasses that wash up on shore often lie undiscovered.

“The numbers only account for the carcasses we’re finding on the coast,” says Frederick Toro, a vet at Santo Tomás University and lead author of the study.