Pakistan, Aug. 13 -- The past few days have seen hundreds of fishing boats and trawlers leave Karachi, Gwadar and Jiwani on 40-day catch-and-sell voyages, hoping diplomacy will accomplish something before their holds are full. That wager looked shakier on Wednesday as Tehran said there had been "absolutely no progress" towards restoring the June understanding with Washington.

A day earlier, the maritime war had moved closer still when a US Navy helicopter disabled a Panama-flagged cargo ship in the Gulf of Oman, around 70 nautical miles off Pakistan, for allegedly attempting to breach Washington's blockade of Iranian ports.

Pakistan's tuna trade with Iran has already been near a standstill since February. Recent strikes on Konarak, Pasa...