For high fish output, make them all males

Fish farming has become a lucrative venture in Kenya, with ponds and cages as the latest frontiers of investment in addition to marine fishing.

But even with these efforts, Kenya is still not able to produce enough fish to meet demand. To address the deficit, Kenyans now look to China for fish imports.

However, importing fish may be a thing of the past if the latest project by the Lake Basin Development Authority (LBDA) succeeds.

The agency is introducing a new technology to promote mass production of fish as the country seeks to address the shortage.

The project, which LBDA launched four months ago, promotes production of male fish which, according to experts, are fast-growing. Their quality is also said to be superior.

“We have a role to play in the government’s Big Four agenda. That is why we want to promote this technology to empower farmers as Kenya seeks to be food-sufficient,” said LBDA Managing Director Evans Atera.

Under the Big Four, President Uhuru Kenyatta hopes to ensure that Kenyans have access to universal health care and affordable housing in addition to ensuring that the country is food-secure. He also hopes to improve manufacturing in his second and last term.

Zaphania Otieno, a fisheries manager at the Government agency’s Integrated Technological Transfer Centre in Kibos, Kisumu County, said mixed sex stock fish increases chances of breeding, which hampers their growth and development.

“Farmers have been introducing catfish to ponds to help control breeding since they feed on young tilapia. However, this has proven counterproductive as the catfish would at times kill tilapia,” he said.

Mr Otieno explained that the new technology to reverse the gender takes advantage of the incomplete development of the fish sex organ at birth to make all of them males.

The fish are fed with feeds laced with testosterone, a male sex hormone, during the first few days. The hormone activates development of the male sex organs.

“This means, when the fish starts to develop their sex organs, all of them become males. Male fish are best for food production. This method is only advisable for production of table fish, where reproduction is not a necessity, and this is what fish farmers require,” said Otieno.

Those who have tried the technology, Otieno said, have reported increased output as male fish take little time to mature, have more flesh and are tastier.

“This is because female fish spend a lot of energy in reproduction, which hampers their growth and quality,” the scientist said. Otieno added that the agency was training fishery students in the new technology. He said the aim was to ensure that farmers diverted from mixed sex fish farming.

“The technology is however complex as it involves highly skilled labour. Conditions for breeding and transportation must also be conducive to ensure the safety of fingerling.”

During breeding, he said, a mature male and female fish are identified. “Eggs are extracted from the female fish and put into a bucket of water laced with saline, at the ratio of nine grammes of saline against one litre of water.”

He added: “Semen is extracted from the male fish and mixed with the eggs in the saline solution. They are mixed properly for a few seconds to allow even fertilisation.”

Fibre-rooted plants such as Nile cabbage are then passed in the mixture to allow the fertilised eggs to attach in the roots before being transferred to another bucket of fresh aerated water for hatching.

“Within three days, the eggs are fully hatched and fingerlings start to move. It is at this point that the feeds with the male sex hormones are introduced,” Otieno said.

Supply of fingerlings to production ponds depends on the client’s demand. Otieno said from three weeks, the fingerlings can survive in an open fish pond. “But before transportation to far-off areas for commercial production, the fingerlings are starved for a few hours before being packed in transparent polythene bags half filled with water, with the other half containing oxygen,” he said.

Otieno explained that starvation ensured that they did not produce much waste once in the bag as this might pollute the water, leading to the death of the fingerlings.

With proper feeding and care, Otieno said, it took six to eight months for the fish to attain a weight of 300 grammes to one kilogramme, the best time to harvest.

“Feeds take between 40 to 60 per cent of the fish farming budget, hence the farmer must be keen on this for quality output,” he said.

Apart from industrial feeds, Otieno said farmers could make their own feeds that contained brans, animal proteins and plant proteins in the ratio of 60:20:20.

Training farmers

LBDA is engaged in research on aquaculture. Otieno said the agency was training farmers on the new technology and supplying them with fingerlings produced through the method. LBDA Chairman Cavince Odoyo Owidi, said the agency would work with national and county governments to ensure Kenyans had access to quality food.

“This is just one of our projects on food security. We have another one on rice and dairy farming. We will also roll out cultivation of indigenous crops and vegetables in the 18 counties that make up LBDA,” Mr Owidi said, adding that the agency would seek partnerships to ensure the projects was sustained.

During the recent blue economy conference in Nairobi, President Uhuru committed to ensuring responsible and sustainable fishing to ensure high-value fish stocks and conserve endangered species.

“We will accelerate development of our fisheries by increasing aquaculture, fish processing and storage capacities,” Uhuru said.

Victory Farms Limited East Africa has committed to construct what will be sub-Saharan Africa’s largest tilapia hatchery. EU pledged 40 million euros (Sh4.7 billion) to support aquaculture value chains in Africa.

“We’ll support small scale fisheries by developing better markets and supply chains, introducing low-cost value addition, upgrading artisanal fisheries and training women and young entrepreneurs on improved use of resources,” Owidi said.