The uncertain future of the world’s oceans is propelling the establishment of saltwater farming in Minnesota
No one believed that Paul Damhof had ordered 20 above-ground swimming pools. His credit card company flagged the purchase and called to verify it. The FedEx guy called believing the delivery was a mistake. The retailer was also perplexed—ultimately allowing the sale but not offering any warranties on the pools when they found out what Paul was doing.
Those pools, knee-high and covered in warnings about diving in shallow water, are now arrayed in two rows in a barn on a rural stretch of highway south of Willmar, Minnesota. Fitted with a homemade system of pumps and air bubblers, they circulate brackish tan water and are each home to several thousand Pacific white shrimp.
“When it’s 10-below outside, I’m in here in short sleeves, sweating,” Paul says, dragging a net through one of his tanks, dredging up a few dozen shrimp. They’re skittish and sensitive to the light, palm-sized and translucent, with pristine shells that end in a tail fan of slate gray and navy blue.
Paul’s operation is called Simply Shrimp, and his family farm—where his grandfather raised beef cattle and which his father later converted into a dairy—is now among a handful of operations in Minnesota developing the nascent practice of inland saltwater aquaculture.
These operations may presage a future where ocean-based shrimping is imperiled by a warming climate, more frequent and powerful weather events, and acidifying oceans. They recognize the inefficiency and footprint of devouring seafood thousands of miles from the source. And they believe they can raise a better product than what’s available from conventional farms a plane ride (or full hemisphere) away from Minnesota.
“We’re having fun,” Paul says, the sentiment confirmed by his humble yet ever-present smile. “We just want to provide the best-tasting shrimp. We want to be second to none.”
Shrimp is by far the most popular seafood eaten in the country—Americans eat nearly twice as much shrimp as salmon, its nearest competitor. Despite a robust shrimping industry in the Gulf of Mexico, a majority of the shrimp we eat is imported from Asia at a cheaper price. And even a cursory glance at the Asian shrimping industry reveals one catastrophe after another.
Conventional Asian shrimp are farmed in tidal pools, and coastal mangrove forests are often cleared to make way for them, removing a natural storm surge barrier against typhoons and a habitat for other species of fish. If poorly maintained, which many are, these pools have a limited lifespan before conditions for farming become untenable. And that’s just a minor logistical issue compared to the industry’s more serious offenses, including forced labor and outright human trafficking.
Beyond the issues that beset shrimping in its traditional form are the complex future ramifications of ocean warming and acidification—conditions that are detrimental to both the shrimp’s spawning patterns and their ability to grow transparent shells to avoid predators. With oceanic conditions uncertain and foreign shrimp an ethical quandary—and with aquaponic farming already on the rise for freshwater fish—the logic follows: Why not usher America’s favorite seafood into a more sustainable and landlocked future?
Blomkest on the bayou
Not much is growing along Minnesota Highway 7 in November. The road is buffeted for miles west of the Twin Cities by the black and tan of tilled cornfields smattered in wispy white as the year’s first snowfall begins to collect in the ditches.
But in the former calf barn at the former Damhof Dairy in the city of Blomkest, it’s 86 degrees and humid. To retrofit the barn for shrimp, Paul replaced the steel skeleton with PVC, sprayed hot-foam insulation, and fastened it with stainless steel screws. The only thing that could rust are the pool frames. (And they’re beginning to—the company was right not to give him that warranty.)
Paul has limited interaction with the shrimp themselves—they arrive from a hatchery the size of an eyelash, disappear beneath the murky water, and reach 20-count size in 120 days when Paul nets them to order. Each tank is outfitted with an automatic feeding device that drops pellets into the water every 20 minutes. Most of Paul’s work is making sure the conditions remain in balance.
“In the mornings when we start, it’s all about managing the water,” says Paul. “Salinity, dissolved oxygen, total dissolved solids, pH, ammonia, nitrite, nitrate, alkalies, carbon dioxide—when we get all our water data together, we adjust feed according to what the water is telling us. Even though there are shrimp in the facility, it’s all about managing the water. Healthy, happy water, and the shrimp come secondary.”
There’s one final piece that completes the ecosystem: Each pool contains a mix of bacteria that eat the ammonia and nitrates the shrimp produce as waste. Paul only ever adds two things to the tanks: baking soda to adjust pH and sugar to feed the bacteria. “No chemicals. No antibiotics. No iodine. No nothing,” he says. “I’m going to call it as ‘all-natural’ as we can get.”
Roadmaps & Roadblocks
Even as the practice becomes more common, inland shrimp farmers must contend with a lack of precedent. Equipment isn’t standardized, best practices are worked out through trial-and-error, and innovations are often patented or highly guarded trade secrets. Paul alludes to collaborating with several firms to develop hatching, growing, and processing technologies, the particulars of which are subject to phonebook-length NDAs.
“In school, I was not into science,” Paul admits. “Biology, chemistry: not my strong suit. And what are we doing here? It’s all that. There’s always something to learn.” Among his lessons: How to engineer a water circulation system strong enough to prevent dead zones in the water but gentle enough not to suck shrimp into the intake. After countless tweaks and fixes to this and other systems, it’s no surprise that the plans for Paul’s second, larger growing facility look nothing like his first one.
Another hurdle is the market. America imports a vast majority of the shrimp it eats because it’s cheap. “I can’t compete with the overseas market,” Paul admits. “I have heating expenses, building expenses; this is not a cheap shrimp.” He sells shrimp out of his front door at $20 a pound, and so far can’t grow shrimp fast enough. But he admits he doesn’t know how much local, premium shrimp the market will bear.
The amount of local investment suggests a strong potential. Tru Shrimp, a division of Ralco, a Marshall, Minnesota-based agricultural science and technology company, is working on a $50 million growing “harbor” in Luverne, Minnesota, coupled with a 4,000-square-foot hatchery in Marshall, with the goal of producing 8 million pounds of shrimp annually.
There are also a number of smaller shrimp farmers, like Paul, scattered across the state looking to fill the niche. Northern Tide Farm in Elgin, Minnesota, is a husband-and-wife operation that began selling shrimp by word of mouth in early 2013. Shrimp Guys, a pair of brothers in Morristown, Minnesota, hope to hand-sell 600–800 pounds of shrimp annually. West Central Bait & Fisheries Company in New London, which raises bait fish and walleye stock, was growing saltwater shrimp as late as 2016, in an effort to diversify their product mix.
Concerns of ecology and economics notwithstanding, Paul remains optimistic because of his ability to produce a better quality product than what’s currently available in the Upper Midwest. We transport a few pounds to the Twin Cities, saute them for 45 seconds in butter, olive oil, and sea salt, and
confirm Paul’s optimism. The shrimp are beautifully firm, a texture that comes from the high salinity in Paul’s tanks, with a sweetness to the flesh that echoes lobster.
“The shrimp we get here in Minnesota: how long was that boat out shrimping? How long did it take to steam back to port, to put them on a plane, to process them, to get them to a store?” Paul asks. “People come here, pick some up, bring them back, they’re eating them in a couple hours. It doesn’t get fresher than that.”