Can Salmon Get Seasick? Debunking a Maritime Myth in Closed-Containment Aquaculture

One of the more persistent objections to farming Atlantic salmon in closed containment tanks aboard ships—especially from traditional industry veterans (hi, Norway)—is the claim that the fish will get seasick and die.

Yes, really. Seasick salmon. Like they’re all little cruise passengers clutching Dramamine packets.

This objection is, I believe, based on a decades-old study in which salmon were packed tightly into a wellboat, sent through terrible weather, and then, surprise, didn’t have a great time. It’s become industry lore: fish + motion = mortality.

But here’s the thing: there is zero published scientific evidence defining a specific lethal motion threshold for salmon. No g-force cutoffs, no wave-height doomsday scenarios. Just vibes—and possibly some guilt from transporting fish like waterlogged cargo.

Let’s replace that myth with actual information, tailored to those of you looking to make rational, risk-aware investments in next-gen aquaculture systems.

A Tank is Not a Wellboat—and That Matters

Let’s start with what the fish actually experience.

In traditional open-net pens, salmon near the surface in stormy conditions can experience vertical accelerations around 0.1g, mostly from surface wave action. At 20 meters depth, that drops dramatically—down to ~0.04g—thanks to wave energy dissipation.

In comparison, large cargo vessels like Panamax or Kamsarmax bulk carriers, even in rough seas, typically generate vessel accelerations in the 0.1g range during storms, with occasional short-lived peaks. And inside these vessels? The aquaculture tanks are rigidly mounted, fully filled, and have no free surface. The fish are entrained within the ship’s frame of motion—meaning they move with the vessel, not against it.

There’s no violent sloshing. No loose water mass careening around. The fish aren’t dodging water walls—they’re calmly riding inside a mobile, neutrally buoyant ecosystem.

Interestingly, by allowing some internal fluid flexibility—like controlled slosh zones or decoupling layers—the system could actually reduce net inertial stress on the fish, much like passive suspension in vehicles. Counterintuitive? Maybe. Effective? Likely.

Wellboats vs. Bulk Carriers: Not All Ships Handle Waves the Same

Let’s clarify another common point of confusion: wellboats ≠ bulk carriers.

• Wellboats are relatively small, short-range vessels (usually <100m), operating in nearshore environments. Their design includes large open tanks many with free surfaces, allowing water (and fish) to slosh around. More modern vessels have closed tanks to limit motion but the prevailing belief among my Viking colleagues was certainly established in a vessel that would be considered obsolete today. In rough seas, this creates chaotic internal dynamics, amplifying motion and increasing stress. They’re also more prone to high-frequency, high-amplitude movement—think cork bobbing in a storm.

• Bulk carriers (like Panamax or Suezmax vessels) are in a different class entirely—230 meters long, 80,000+ DWT. These ships are designed to cross oceans with enormous stability. Their long roll periods and high mass mean they ride through wave systems rather than getting batted around by them. When equipped with fully-integrated containment tanks, these vessels offer a more inertially stable environment than even some nearshore net pens.

So no, your closed-containment salmon won't be tossed around like they're in a seafood washing machine. They're basically in a floating building.

Establishing Safe Motion Limits: What the Data Actually Says

Since there are no salmon-specific thresholds for motion exposure (because the fish can’t file OSHA complaints), we turn to a useful proxy: ISO 2631-1 human vibration exposure guidelines. These are commonly used in animal welfare contexts for setting safe motion standards.

Here’s how that translates:

• Target operational limit: ≤ 0.05g sustained acceleration

• Maximum storm exposure: ≤ 0.1g for up to 8 hours

Both values fall well within the performance capabilities of large vessels, especially when paired with intelligent tank design. And with CFD (computational fluid dynamics) simulations and RAO-based (Response Amplitude Operator) seakeeping analysis, we can define the exact wave conditions under which operations remain compliant with these thresholds.

This isn’t guesswork. It’s a predictable, model-driven environment—exactly what you want in an investment landscape already full of volatility elsewhere.

So, Can Salmon Get Seasick?

Sure, if you pack them at transport densities and pound through a winter storm.

But in a sealed, stabilized containment system onboard a 230-meter ship designed to move iron ore across oceans? No. That’s not a sickness scenario. That’s a scalable aquaculture opportunity with built-in motion mitigation—and operational limits defined by physics, not fish folklore.

Conclusion: Time to Retire the Myth

Let’s not confuse outdated anecdotes with modern engineering. The idea that salmon can’t survive in tanks aboard ships simply doesn’t hold water—literally or figuratively.

We have the models. We have the motion data. We have vessels that regularly cross oceans more smoothly than some high-speed trains.

What we don’t have is any reason to believe that salmon, properly housed in inertial tanks aboard well-designed vessels, can’t thrive.

And if the skeptics are still worried, we’ll reserve them a tank of their own—with a window seat.

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