How to Embrace Fish Farming
From mussels to kelp, our oceans are telling us what to grow
Fish is among the most challenging subjects in food; roughly a billion people rely on seafood for their primary protein source. Yet many fish populations are ten percent of what they were a hundred years ago, and the oceans (which comprise around 95 percent of the “habitable” space on earth), largely because they’re international, remain little understood, minimally managed and regulated, and badly policed. One solution is to farm fish, and yet most recent aquaculture “solutions” have simply replicated the mistakes of land agriculture. Still, there are newer ways of raising fish that make sense, and this piece, which we originally published a couple years back and remains relevant, explores that subject. — Mark
Fish farming has earned a negative reputation, and not without valid concerns. The practice operates within systems that diverge from the natural order, striving to rear fish in conditions that, if not carefully managed, can potentially jeopardize both ecosystems and the health of consumers.
The farming of bivalves and sea greens is quite literally doing the opposite: Bivalves, such as mussels, oysters, clams, and scallops, along with seaweed, require zero feed, fertilizer, or antibiotics. That they generally stay put is better for ecosystems.
“Farming bivalves and seaweed is possibly the most sustainable harvest we have from the sea,” said Ryan Bigelow, project director at Conservation Alliance for Seafood Solutions.

Both bivalves and seaweed filter out contaminants from the waters they consume, breathing life back into our oceans. A single oyster can filter upward of 50 gallons of water a day, which adds up exponentially when accompanied by an entire reef.

In recent years we have seen breakthroughs in fish-feed alternatives, typically composed of plant proteins, which can drive genetic manipulation and behaviors, even converting certain species from carnivores to omnivores. While this trade might seem efficient compared to land animals, like cattle, the question remains: Why aren’t we emphasizing foods with zero inputs?
“Looking back, the big mistake made was that no one looked out at the ocean and asked what’s unique about it as an agricultural space. Instead, it was driven by markets,” says Bren Smith, founder of GreenWave and author of the James Beard Award-winning book, Eat Like a Fish: My Adventures Farming the Ocean to Fight Climate Change.
“The thought was, ‘people eat salmon and tuna, so let’s grow salmon and tuna.’ But that’s a wild palate. When you actually ask the ocean what to grow, it says, ‘why don’t you grow things that don’t swim away and things that you don’t have to feed?’ That’s what’s unique about the ocean as an agricultural space. It’s pretty simple.”
Smith’s passion for regenerative ocean farming, or what he often refers to as “3D ocean farming,” wasn’t where the Newfoundland native started — as a young commercial fisherman in the icy waters of the Bering Sea. When Smith was still in his early 20s, he began noticing that fish populations were steadily disappearing. It was time to look elsewhere.
“My journey is the journey of multiple ecological collapses in the ocean,” says Smith.
Newfoundland was on the front lines of climate catastrophe related to overfishing with the 1992 moratorium on fishing Atlantic cod, resulting in approximately 30,000 fishermen and fish plant workers losing their jobs.
“Seeing my people walking around like hungry ghosts, just no sense of meaning — sure, the government was doing buyouts and trying to create jobs, but people wanted to fish,” said Smith, reflecting on the largest industrial closure in Canadian history. “That was the real wake-up call. That was my shift to aquaculture. I was like, ‘OK, what’s a way to stay on the ocean? What’s a way to die on my boat one day?’”
Smith took a stab at aquaculture but wasn’t impressed with his results. Many farmed species are the ones that thrive in the wild: When these species are jammed together in confined pens, things generally go awry.