The likeliest explanation is that new sanctions, designed to cut off Iran from the global financial system and bedevil its oil exports, are doing serious damage to its shipping business.

FORBES: Iran Sanctions: A Tale of Two Fleets

The paths carefully avoid major shipping lanes, to limit the risk of damage from dragging anchors.

WSJ: A Dive Into the Digital Deep

So questions about drilling rights and shipping lanes, let alone who bears responsibility for environmental damage, are somewhat murky.

CNN: Countries in tug-of-war over Arctic resources