Are underwater farms the future of food production?
Bren Smith used to hustle oysters on the streets of Brooklyn, New York. After two hurricanes in a row wiped out his crop, the fisherman took his ocean farm ''3D", and says the model could help boost food security.
Locked in place with hurricane-proof anchors, horizontal ropes sunk below the surface of the sea form the layered framework of Smith's three-dimensional ocean farm. Streamers of kelp grow downwards, scallops hang in nets and mussels in special socks, with oysters in cages below. Clams grow under the mud on the sea floor.
"We went 3D and started growing a whole mix of species - but only species that you don't have to feed; that are zero input.
"So no fresh water, no fertiliser, no feed, which makes it the most affordable food to grow," said Smith, who dropped out of school at the age of 14 to work on industrial ships hoovering up vast quantities of fish, sometimes illegally.
Kelp sucks up five times more carbon than land-based plants while oysters can filter 189 litres of water a day, said Smith.
The easily assembled underwater farms are also a magnet for fish and help regenerate reefs.
So far the 3D concept, pioneered by Smith's nonprofit GreenWave, has drawn interest from would-be farmers from the US, Brazil, Chile, Britain and South Africa.
GreenWave has plans to build "reefs" of farms, based around areas with a land-based hatchery and a pool of companies nearby to buy the seaweed and shellfish.
With low capital costs and minimum skill requirements, ocean farming can use a "nail salon model of the sea" to grow fast, said Smith.
Farmers who can't afford land are eyeing ocean plots, which cost about R260,000 plus a boat to set up in the US and can net up to R2-million a year, he said.
"If we have enough of these farms, we can have a major impact," said Smith.
"This addresses serious issues of food security and economic opportunity."
Smith described kelp as a "game changer" because it's so fast-growing and has wide uses, from food to cosmetics, animal fodder and fertilisers.
"It's the soy of the sea, but it's not destructive," said Smith.
While it might not yet be a common menu item, Smith sells kelp to companies such as Google, which makes seaweed burgers for its cafeterias, and he ranks the roasted kelp noodles sold in a New York restaurant as his favourite way to cook the plant.
"Imagine being a chef - there are thousands of kinds of vegetables you'd never seen or cooked or tasted before. It's the beginning of an entirely new culinary adventure," he said.
Alongside GreenWave, which trains farmers and provides seeds and equipment, a separate company takes responsibility for processing plants and market development for the ocean farms, promising to buy 80% of the produce at triple the market rate, selling the shellfish and kelp to local restaurants and other businesses.
A World Bank report last year said global food security could be strengthened by large-scale seaweed production for human and animal use. An increase to 500,000 billion dry-weight kilograms a year by 2050 could boost the world's food supply by 10%, it said.
Massive seaweed farming expansion could help tropical developing countries reduce poverty and climate change-linked migration, and improve their ecosystem management, it added.
Growing seaweed in polluted waters can also soak up contaminants and later potentially be used to generate energy.
"We need to farm our way into a new economy and into a new revived ecology," said Smith . - Reuters
• This article was originally published in The Times.