How an enormous fish farm in Homestead hopes to change the seafood industry

Miami Herald

27-02-2025

Salmon farms normally occur in the fjords of Norway or Chile, not on the hot, humid flats next to the Everglades. But Atlantic Sapphire, a new type of on-land salmon farm, is betting on South Florida as the perfect spot for a cold-water fish farm.
When you drive into the Homestead property, which sits between tree farms and Everglades National Park, it looks more like a massive warehouse than an aquaculture facility. But inside the 9-acre white building, 3 million salmon swim through cold salty water.
Every week, the facility, which took three years to build and opened in 2020, ships out 300,000 pounds of salmon to grocery stores such as Publix and Sprouts in Florida and beyond. It's one of only a few indoor salmon farms in the U.S., and the largest one in the world, according to Gunnar Aasbø-Skinderhaug, deputy CEO and CFO.
It also just might represent the future of aquaculture in a world altered by climate change, pollution and population growth.
Why South Florida for salmon?
Two reasons, really, said Aasbø-Skinderhaug as he strolled a long hallway in the indoor farm: The market and the water.
South Florida's unique geology means we sit 1,000 feet above the Floridan Aquifer, which flows underground south from around Gainesville, Florida. It's as salty as the ocean, and untouched by the modern world. 'It hasn't seen daylight in tens of thousands of years,' says geologist Fred Bloetscher, of Florida Atlantic University, who is not involved with Atlantic Sapphire.
To access the water, Atlantic Sapphire drilled two wells, one to 1,200 feet, the other to 1,800 feet. They then blend the water to achieve the optimal salinity for each stage of the salmon's life. That means the fish are swimming in water with no microplastics or other modern contaminants in it.
'The number one thing you need when you farm fish is water, and we have that here,' said Aasbø-Skinderhaug. 'There are very few places on the earth that have this geology.'
Then there's the market. The U.S. is by far the largest salmon market on the planet, consuming about 926 million pounds of salmon per year, more than three times the next largest market, France. Eighty to 90% of that is farm-raised, and 95% of that is imported, mostly from Chile and Norway.
'Making the salmon here is smarter, both from an economic perspective and an environmental perspective,' said Aasbø-Skinderhaug. 'We don't have to create the market. The market is there.'
How to make a Florida warehouse like a fjord
Making life livable in Florida for cold-water fish requires a $250 million building with a matrix of enormous pipes, 36 450,000-gallon fish tanks with a constant flow of water, and 241 employees to keep it running smoothly.
Before entering the vast rooms full of fish tanks, all workers and visitors don boots and dab them with disinfectant. Hygiene, it turns out, is one of the major advantages of indoor fish farming.
'In the ocean, the fish are exposed to whatever the ocean gives you,' said Aasbø-Skinderhaug, 'diseases, pollution, parasites. Here we control everything.'
Every five weeks, Atlantic Sapphire receives trays of fertilized salmon eggs from either Iceland or Norway (fish are bred, akin to cattle, to have certain characteristics, such as fast growth).
Once those eggs hatch, the fingerlings go into tanks of fresh water that emulate being born in a river.
Each of the six tanks has 50,000 little fish in it.
When they grow to around 6 inches, they can handle salt water. Human hands never touch them. They flow through tubes and shoot out, as if from a waterfall, into the massive, 40-foot deep tanks with brisk cold current. The fish are constantly swimming, just as they would be in the wild.
In the chilled room, every once in a while a fish jumps gracefully, and PVC tubes deliver fish pellets made of krill meal and other marine and plant-based materials.
Aasbø-Skinderhaug said growth rates are a tad faster indoors than in outdoor pens.
'It's quicker because we can control the environment better. In Chile and Norway, sea water temperature varies, it's cold in the winter and warm in the summer. In our facility it's stable. We keep it at 14 C (57 F), and that's the most optimal temperature that secures good fish health, good growth and low mortality. If you get colder they'll grow slower. If you get warmer, it's not good for the fish.'
He said 1.3 pounds of feed converts to 1 pound of whole fish (not fillets). That's a more efficient 'feed conversion ratio' than poultry or beef.
After about 22 months, when the fish reach 8 pounds, they're ready for harvest. Technicians drain the tank and the fish flow through tubes to the processing area, where they're processed in-house. Atlantic Sapphire sells the leftovers to pet food producers.
Processing is fairly uniform across the industry, said Damien Claire, chief marketing officer. Fish are electronically stunned unconscious and bled out, then cooled again and filleted mechanically.
'If you don't stun first … it's not very good for animal welfare,' says Claire. 'And second, the stress of not being stunned and bleeding out generates lactic acid — it's very bad for the quality. It's very standard in the industry. Everyone does it.'
Where does the wastewater go?
One of the main complaints about net pen farming in Chile and Norway is that the farms, which sit in coastal areas, pollute surrounding waters with feces, parasites and fish illnesses. Farmed fish sometimes receive antibiotics, and if they escape — which they often do — they may breed with wild populations, damaging the genetic quality of indigenous salmon.
Land-based farming combats those factors, but still produces wastewater with feces. To treat fecal fish waste, they've built a sewerage treatment plant within the building. 'It's quite similar to a municipal wastewater treatment plant,' said Aasbø-Skinderhaug.
Mechanical filters take out large particles, bio filters remove ammonia and smaller particles, then a degasser removes CO2 that fish produce.
The filters, which do contain nitrogen and phosphorus, go to a landfill. Aasbø-Skinderhaug said in the future they'd like to sell that solid waste as fertilizer. 'At the moment we don't have enough of that to make it economically viable.'
Most of that filtered water is then recirculated through the fish tanks via a Recirculating Aquaculture System. What they don't reflow through the system gets pumped 3,000 feet down, below the Floridan Aquifer, into a boulder field.
Geologist Bloetscher says that the water in the boulder zone flows east to west, and that it's confined by rock layers. 'The stuff does not migrate between the zones,' he said. He estimates that it would travel 500 to 600 miles off shore into the Gulf of Mexico before it intersects with the bottom of the ocean. That could take centuries.
Bloetscher has been involved with two studies on deep-well injection wastewater disposal in South Florida.
Both studies (one with the University of Miami, one with the EPA) concluded that deep injection wells were the safest alternative for wastewater disposal in South Florida.
The carbon footprint
Salmon farmed in Norway or Chile must travel from net pens to a processing plant, then a local airport, an international airport, an international flight to Miami. Then to a customs warehouse, a distribution warehouse, and finally a grocery store.
Atlantic Sapphire processes their fish onsite, and Publix picks them up. Other stores and restaurants go through fish distributors, but the process is simplified and the mileage and time cut dramatically.
A 2016 study comparing carbon emissions of net pen fish from Norway with domestic land-raised salmon sold within 250 miles of production found that land-raised fish had half the carbon footprint.
Of course the study was not specific to Atlantic Sapphire, which must cool water from about 70 F when it leaves the Floridian Aquifer to 57 F for the fish.
Aasbø-Skinderhaug said the plant partners with FPL so that more than 40% of their power comes from solar, and they plan on installing solar panels on a second building in the future.
For the most environmentally responsible farmed salmon, the Monterey Bay Aquarium's Seafood Watch recommends U.S.-raised land-based salmon raised in recirculating water systems like the one at Atlantic Sapphire.
Fish futures
Atlantic Sapphire is focused in the Southeast, in all Publix stores as well as some Sprouts markets. They ship as far away as California, and sell to Chef's Warehouse, a distributor who in turn sells to restaurants.
The aforermentioned second building will have larger tanks, more water treatment capacity and those solar panels on the roof.
At nearby South Florida Publix supermarkets, customers are noticing Atlantic Sapphire's brand, Bluehouse.
On a recent visit, a customer perusing the orange filets in the cooler spotted Bluehouse and asked the fishmonger for a pound.
When asked why he ordered the indoor salmon, he didn't mention carbon footprint or microplastic. For him it was more simple. He said it bridged the gap between net-raised salmon and wild fish. 'It's not as fatty as the net-raised stuff,' he said, 'but not as lean as the wild fish. I really like it.'
This story was first published by the Sun Sentinel and was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative founded by the Miami Herald, the South Florida Sun Sentinel, The Palm Beach Post, the Orlando Sentinel, WLRN Public Media and the Tampa Bay Times.