Lake Kariba on the Zambezi River border between Zimbabwe and Zambia used to be dotted with hundreds of commercial fishing rigs, while local fishermen in small makeshift boats would catch enough bream for their livelihood.

Now the fishermen are standing on shore praying for rain as drought has shrunk the water level of the world's biggest man-made lake by volume to a record low.

"It's so bad that on a bad day you can catch just a couple of fish, just enough to eat on the day or exchange for cooking oil or a small packet of cornmeal," said one of them, Cyril Murinda.

"We just hope that God hears our pleas for rain and the dam fills up so that we can get back to fishing, otherwise we will just starve."

Lake Kariba has fallen to 12 percent of its capacity, hitting the fishing industry and also vital hydroelectric power production in Zambia and Zimbabwe, according to the dam's operators.

This time last year, the lake was 51 percent full.

"We are lower than the lowest levels we had in 1995 and 1996," engineer Munyaradzi Munodawafa, chief executive of the lake's managers Zambezi River Authority, told AFP in a telephone interview.

Kariba's maximum storage of an enormous 185 cubic kilometres (44.4 cubic miles) of water makes it the earth's largest man-made lake by volume.

John Chiringa, who runs a fishing company in Kariba town, said kapenta -- a small, sardine-like fish -- are hunted commercially by some 400 boats, known as rigs, at any one time.

The rigs employ thousands of people. They operate at night, attracting the shoaling fish with lights and scooping them up in dip nets.

"Climate change is threatening the industry and some people have moved off fishing," Chiringa said.

"In the last few months, there were very few rigs who managed to catch a tonne in a month where in the past they could catch up to four tonnes within a month."

- 'Fishing for survival' -

The low water levels have dried up business, Hakurotwi Shonhiwa, chairman of the Indigenous Kapenta Fishers' Association on the Zimbabwean side of the lake, told AFP.

"There is no profit and people are just fishing for survival."

Fisherman Wonder Dipuka says his family faces starvation unless the water rises.

In a country saddled with massive unemployment, Dipuka earns a living and pays school fees for his children through fishing, but the low water levels have left him struggling to catch enough to put a meal on the table.

"It's now very difficult to survive because there are no jobs in Kariba," he said, while fishing from the shore and watching for any hint of a bite at the end of his line.

Dipuka said that with an average daily catch of 20 kilogrammes (44 pounds), he could pocket $40 a day, but now he can barely catch one kilogramme.

The region's severe drought has been caused largely by poor rains due to the El Nino weather phenomeon. And the hardships from low water levels stretch far beyond the shores of Lake Kariba.

Located 400 kilometres (250 miles) downstream from the Victoria Falls, the dam feeds water to two hydroelectric stations capable of generating 750 megawatts of electricity for Zimbabwe and 600 MW for Zambia.

The Zambezi River Authority is rationing the flow of water used for power generation and at the current rate it will last just five months, CEO Munodawafa said.

But he ruled out a total shutdown of the power generators.

"Although we don't expect a vast increase in the water volume, a complete shutdown is not likely," Munodawafa said. "We may have to further ration."

Heightened rationing means more blackouts in both countries.

Zimbabwe is already suffering from perennial shortages, forcing the Zimbabwe Electricity Supply Authority (ZESA) to cut power to some parts of the country for up to 10 hours at a time.

ZESA spokesman Fullard Gwasira said the authority had adopted "mitigatory measures" including power imports and turning to alternative energy sources to maintain local supplies.