Farmers in Kenya's eastern and northern drylands have found a way to stay afloat as water becomes scarcer: cultivating catfish.

"This is my new source of income," said Sylvester Kinyori, 32, who operates a kiosk in Isiolo town where he sells fish products from local farmers who have turned to aquaculture.

Kinyori, who hails from Turkana, a pastoralist area in northeast Kenya, now earns a living from selling cooked fish fingers prepared from catfish fillets, eggs and bread.

Small-scale farmers started rearing fish here four years ago, after an aid agency introduced them to a simple way of trapping and storing rainfall run-off in what are known as "home dams".

The water is stored in reservoirs sunk in the grounds of a household compound, fitted with a thick polythene lining to stop it percolating away into the soil.

The technique was developed by members of the Yatta community in eastern Kenya who had teamed up to end their reliance on food aid, called "mwolio" in the local Kamba language.

After the success of "Operation Mwolio Out", in 2009 ActionAid Kenya decided to introduce home dams to hundreds more households in east and northeast Kenya.

These regions are semi-arid, sometimes receiving annual rainfall of less than 150 mm (5.91 inches). They have seasonal rivers, some of which flood for just a few hours after heavy rains, leaving women with no option but to dig deep into the riverbed to access the little water left under the sand.

Drying climate

A long-term analysis of Kenya's climate trends, published by the U.S. government in 2010, showed rainfall had declined in central food-producing areas since the 1960s.

And it predicted large parts of the country would experience a drop of more than 100 mm in long-season rainfall by 2025, along with a temperature rise of around 1 degree Celsius from 1975.

That underlines the importance of efforts to help farmers adapt to shifts in the climate.

When it rained in 2012 in the Kitui and Isiolo regions, some households managed to trap water in their home dams. They then decided to introduce young fish into the ponds.

John Njiru from Mashamba village in Mbeere explained that nearly all the farmers started with the African tilapia, which had been popularized across Kenya by the government as the best species for aquaculture on farms.

But the yields were disappointing, prompting a change in tactics when it rained again in 2014.

"We all went for the catfish species, given the fact that those who tried (it) in 2012 were not as disappointed as some of us who went for tilapia," said Njiru.

In 2015, those who enjoyed a good haul of catfish were motivated to invest more, so as to profit from the unusual September rains linked to the global El Nino weather phenomenon.

Njiru said the village experiment had shown catfish – which have distinctive whisker-like filaments around their mouths – could be more resilient to a harsh climate than tilapia, withstanding higher temperatures.

"We are happy because we can eat the fish, and sell it to generate income," he told the Thomson Reuters Foundation. "It's my hope that fish farming in this region will stand the test of time given the tough and changing climatic conditions."

Mature catfish sell for KES 500 ($4.93) each at the local market. To hasten their growth, many farmers also breed tilapia to feed the catfish.

Breeding business

Meanwhile, growing demand for catfish fingerlings is spawning more business for local people. Rhoda Mwende from Kanyonga village in Mbeere South Sub-County has mastered the complex art of breeding and hatching the young fish.

The single mother of three, who just five years ago depended on food aid, sold 40,000 catfish fingerlings to local farmers after the September rains, earning her KES 400,000.

Following the long rainy season in April, she sold more than 80,000 fish, earning her over KES 800,000. She has bought 1.5 acres (0.61 hectare) of land with the proceeds, where she lives with her children and her mother.

Mwende has mastered the entire catfish breeding process – from injecting the female fish with hormones to stimulate egg production, to squeezing eggs out of the fish and removing semen manually from male fish to fertilize the eggs.

"It is amazing to see people who depended on food aid just a few years ago turn around their lives using an idea nobody had ever thought of," said Dinah Wambua, field officer for ActionAid in Makima, Mbeere.

The farmers harvest the fish from the home dams when water levels drop, and wait again for the next elusive rains before introducing new fingerlings.

A full-sized home dam – about 20 feet (6.1 m) square and eight feet deep – can provide water for an average family of eight for domestic use and irrigation for at least an acre of land for a year, according to Njue Njangungi, agricultural extension officer for Mbeere's Kyome Thaana ward.

Such a dam can also hold 1,000 catfish fingerlings. "Home dams are a double win for us," said Elizabeth Musyoka from Kithambioni village in Kitui, east of Nairobi.

"We now have water, and our children can enjoy a delicacy, which gives them an important protein they had always missed."