The Malawian government admits that this border dispute is a source of concern, but its economy needs oil, to diversify away from tobacco.

While oil could revive the country's economy, Mwangonde doubts that oil wealth will trickle down to the locals. "A lot of the people who live around the lake are fisherman, they have no skills at all to work in an oil industry," he says.

It's a complaint common to many resource-rich African nations: ordinary people don't benefit from that wealth. But Pitman hopes Malawi's new president Joyce Banda can do things differently.

"I think Joyce Banda has (an) amazing opportunity now to open it up, to allow this to be done in a more accountable way so that there isn't the opaqueness, there's more transparency and we can avoid the spiraling inequalities which occur through oil wealth," he said.

If generations to come are to benefit from the lake -- from its food and potentially its oil -- then Malawi's government faces a challenge of leadership and resource management. Because to fail, could turn the lake from an asset to a liability.