The pair, lawyers both aged 35, rely on a symbiotic method called aquaponics in which waste from the captive fish feeds plants grown not in soil but in pond water filtered through their roots to be reused for the tanks.

Two years ago, Martinez and Lopez started their business in Barbosa, a suburb of the capital Havana, with a government loan and some private savings.

They built 12 ponds of 20 cubic meters each.

In their ponds, the tilapia need six months to grow to the required size of 400 grams (14 ounces) for human consumption.

“We sell them (the fish) here in the community as we are a local development project, but part of the production will be sold in the tourism sector so that we can earn the money we need to continue” with the project, said Martinez, co-owner of the enterprise called JoJo Aquaponico.

When they have completed building their three greenhouses, the pair also hopes to be able to grow 36 tons of vegetables at a time.

Projects like these are increasingly important for feeding Cuba’s 11 million inhabitants, under US sanctions for the last six decades.

The communist nation is experiencing its worst economic crisis in three decades, with shortages of food, medicine and fuel.

“Our idea is to bring this knowledge … to everyone who wants to … produce fish,” said Lopez. “It is a viable and sustainable solution.”

Before the economic crisis of the 1990s brought on by the disintegration of the Soviet Union, an important ally, Cuba had a fleet that captured some 100,000 tons of fish in international waters every year — most of it sold at home at subsidized prices.

Its own coast is shallow and low in nutrients, according to experts, and overfishing has further diminished stocks around the island.

Another hurdle is a growing shortage of engines and fuel for fishing boats, Food Industry Minister Manuel Sobrino said on local television recently.

For the last three years, Cuba has taken in less than 12,000 tons of fish per year.

Last year, the country sold seafood worth some $54 million to clients abroad as it desperately needs foreign currency.

Fish cultivation has also taken a hit.

Official figures show that between 2018 and 2022, production of catfish — another freshwater species raised in captivity — dropped from 6,286 to 1,355 tons.

Agriculture yields in general fell by as much as 35 percent from 2019 to 2023 in Cuba.

In July, deputy prime minister Jorge Luis Tapia proposed that Cubans start cultivating their own fish at home — a practice that was widespread in the desperate times of the 1990s. The suggestion was met with incredulity.

As the government scrambles to address the food shortage, it approved a law in 2019 to allow fishermen to sell their catches directly, without state intervention.

Small businesses have increasingly been buying fish from individual fishermen but with the mark-up, ordinary Cubans cannot afford to buy it from them either.

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