A rise in violence from pirates over the past year has made the Gulf of Guinea the most dangerous region for seafarers.
A study from the US-based group Oceans Beyond Piracy says these incidents included an increase the use of “kidnap-for-ransom” tactics.
The State of Maritime Piracy 2015 says the West African situation contrasts with the coast on the other side of the continent where international efforts have suppressed major attacks.
The report says pirates in the Gulf of Guinea have largely turned their focus away from the oil tankers they used to rob for their cargo.
That’s no longer lucrative because of low oil prices, so there’s since been a shift to kidnapping for ransom, reports the BBC.
These attacks are now said to increasingly involve violence.
Nigerian security forces have been responding to the threat but the pirates have only moved their activities further into international waters.