Russia and Ukraine are battling over underwater mines as the global food crisis worsens | CNBC |

William Alberque, director of strategy, technology and arms control at the International Institute for Strategic Studies, told CNBC that Ukraine would have been "crazy" not to have mined the approaches to its ports and that its reluctance to remove them now was rational.

"You can completely understand why Ukraine would be using sea mines right now. The chance of amphibious assault on Odesa has been something explicitly made by the Russians."

But strategists agree that Russia is now using the mines to its economic and military advantage.

"The mines are a real barrier to grain exports from Ukraine ... and they're a big problem," Sidharth Kaushal, a naval power expert with the Royal United Services Institute think tank, told CNBC Thursday, noting that Russia had been strategic about the mines.