Ugandan navy speedboats sliced through murky Lake Edward towards a fleet of wooden canoes carrying illegal fishermen from the Democratic Republic of Congo, hightailing it back to their own waters.
"Stop the boat, hands up, surrender any weapons," yelled Lieutenant Deogratius Kato as the soldiers surrounded a motorised canoe after a 20-minute chase, pointing guns at two terrified fishermen.
The rest of the boats escaped to the safety of Congolese waters, leaving a trail of fishing nets in the water, some tight mesh drift nets that trap everything, including juvenile fish and feeding birds.
Kampala has stepped up patrols in recent months to crack down on illegal fishing on Lakes Edward and Albert, straddling Uganda and Congo.
The missions have led to the arrest of hundreds of Congolese fishermen and sent tensions soaring between the two countries whose armed forces engaged in deadly clashes on Lake Edward -- the smallest of the Great Lakes of eastern Africa -- in July.
Both lakes lie mostly in Congolese territory where uncontrolled fishing has depleted stocks driving fishermen into Ugandan waters where officials are now clamping down on overfishing.
"Since we started our campaign against illegal fishing, we have seen fish stocks increase on our side, hence the influx of fishermen from the Congo," said Brigadier Michael Nyarwa, head of Uganda's navy.
The lakes are home to catfish, tilapia and Nile perch, which are consumed locally and exported.
Landlocked Uganda's fishing industry accounts for three percent of GDP and employs more than 700,000 people, according to official figures.
Worldwide, overfishing in lakes and oceans is upending delicate ecosystems, but also impacting the livelihoods of millions.
It has led to bloodshed in Uganda and Congo. In July, their armed forces clashed on Lake Edward, where Uganda's small navy deployed in April, leaving two Ugandan soldiers and three civilians dead.
Kato claimed Congolese troops, "ambushed us in a civilian boat".
"We think they did it to intimidate and threaten our operation", which he said is preventing hungry, ill-disciplined soldiers from stealing fish and engaging in piracy on the lake.
Likewise, a Congolese fishing association has accused Ugandan troops of arbitrarily arresting fishermen and shaking them down for money.
In the latest incident, Ugandan authorities this week denied killing four Congolese fishermen whose bound and bullet-riddled bodies were found floating in Lake Edward.
According to Lieutenant Colonel James Nuwagaba, a commander of the Lake Edward operation, the first 200 fishermen who were arrested pleaded guilty and were released, "but some of those that we pardoned and sent back, returned to our waters".
Uganda has taken a tougher stance since, with nearly 100 Congolese arrested, charged and imprisoned for up to four years.
The two men taken into custody last month during the operation witnessed by AFP were in their mid-50s.
Father of seven, Luka Kasereka, said he was just looking for fish. "Our side there is no fish. It's over," he said.
He and Paluku Kavutsu pleaded guilty at a magistrate's court and were sentenced to four years in prison for illegal entry into Uganda, illegal fishing and use of illegal nets.
Kato said the biggest challenges are Kinshasa's "failure to cooperate" and the threat of armed Congolese rebels who regularly seize fishermen and their equipment for ransom.
Resource war scales up
The war over the ever-scarcer resources of the region's lakes is spreading.
To the south, Rwandan and Congolese fishermen are plying the waters of Lake Kivu to feed fast-growing populations on both shores.
But competition need not be deadly, nor damaging, said Egide Nkuranga, a Rwandan environmentalist.
"Countries that share water resources have to come up with common agreements that protect the resources and also help replenish overexploited stocks," he said.
"The region risks depletion of some fish species, and local fishermen need to be trained and sensitised on the protection of endangered fish species."
Back on Lake Edward, tentative talks are under way, a Ugandan military source said, aimed at resolving issues of illegal fishing, migration and piracy in a bid to end the bloodshed.