Somalian porters offload goods on April 24, 2013 in the sea port of Mogadishu from a foreign vessel. - 

A new report out this week shows that while pirate attacks off the Somali coast have plummeted, there's a growing threat on the other side of the continent. West African pirates are launching bold attacks, mostly targeting oil cargo off the coast of Nigeria. The BBC explains:

Because successive governments [in Nigeria] have failed to develop sufficient domestic oil refining capacity, Nigerian waters are full of tankers exporting crude oil and importing refined petroleum that are vulnerable to attack, says BBC international development correspondent Mark Doyle.

Corruption and, until recently, armed rebellion in the oil producing areas, have led to the development of an entire, well-organised industry for stealing - or "bunkering", as it is known in Nigeria - oil products, he says.

At the same time, the findings show a 78% drop in piracy off Somalia last year compared with 2011.

The BBC's Will Ross joins Marketplace's Mark Garrison from Lagos to discuss. Click on the audio player above to hear more.