By far the majority of the world's traded goods travel by ship, but a lack of crew for those ships from the global pandemic could inflict operational constraints that will, ultimately, harm world trade.
According to the International Maritime Organisation, there are around 400,000 seafarers from around the world stranded on ships. Crew continue to work but cannot be relieved.
This "deepening crew change crisis threatens trade and maritime safety", the IMO has said. It is estimated that the same number of seafarers are unable to join ships.
The impasse can be resolved by categorising seafaring as a key job. Marking World Maritime Day (24 September), the United Nations Secretary-General, António Guterres, has renewed his appeal to governments "to address their plight by formally designating seafarers and other marine personnel as 'key workers'".
Anecdotally, ports that have enabled crew changes, such as Singapore, have seen ship calls hold up during the pandemic.
Mediterranean bunker sources say that this has helped the situation in Gibraltar where vessel calls have remained "steady".
"Gibraltar demand [for bunkers] has been aided by the fact that crew changes have remained possible locally, the airport was never closed," a source said.
And while the number of players in the West Med ports has not changed, barges from quieter ports, such as Barcelona, have been redeployed there, the source added.