Randall Benton/Sacramento Bee/MCT via Getty Images

The “salmon cannon” isn’t even the first time US scientists have flung aquatic creatures into the air.

Humans everywhere were captivated over the weekend by a viral video of salmon being transported from one estuary to another through a giant overland pneumatic tube — a.k.a. the “fish tube.”

The jaunty video, which shows fish shooting through the sky like checks in a bank drive-thru, chronicles the work of a bioengineering company called — wait for it — Whooshh Innovations. The footage originated in a tweet from live stream news platform Cheddar, which quickly went viral:

From there, the denizens of the internet did their thing, with many reacting to the fish tube like it was the ultimate summer theme park ride:

But before you grab your floatie and head to the nearest estuary, there are some important questions you may want to consider first. Like: Is this magic? Is it dangerous for the fish? Do the fish enjoy the ride? And is all this actually helpful or harmful for the environment?

As it happens, behind this meme is a real environmental problem that’s been brought to us by a combination of agricultural deforestation and climate change. And the tube, as fun as it looks, actually is dangerous for the fish, or at least has been in the past. But before we get into all that, let’s start by explaining how exactly all this works.

So how does the fish tube work?

The fish tube works not by magic but through physics. As Whooshh’s lead bioengineer Jim Otten explains in a company presentation video, the fish tube is a simple pneumatic tube that’s been adapted to be fish-friendly.

Javier Zarracina/Vox

The basic pneumatic tube system uses variations in air pressure to push things through it. Pneumatic tubes have historically been used to transport everything from mail to fruit to steel. These specific tubes have been altered to be soft and flexible, which allows the company to “create a pressure differential across the fish.”

In other words, behind the fish is a lot of air pressure. In front of the fish is nothing but sky.

Whooshh / YouTube
The air pressure propels the fish up while the angle of the tube allows for steady transport.

To keep the fish totally breathing on its bogus journey, the tube comes equipped with water misters every five feet or so. The pressure put on the salmon that enter any of the tubes is roughly equivalent to the pressure it might face in its natural environment — about one-and-a-half feet of water, according to Otten. To induct it into the tube, the fish slides into an initial chamber that functions like an air lock, allowing pressure to be equalized around it before the tube opens and it’s sent on its way.

The tubes can hold around five fish at once without losing too much pressure to transport them. That creates the pressure equivalent of about 11 feet of water total, which is enough to move all the fish along like airport luggage on a really fast conveyer belt. The company claims this allows it to handle the migration of entire schools of salmon in just a few hours, but a longer tube means fewer fish. In 2017, the company tested out a 1,700-foot tube called the Whooshh Fish Transport System (WFTS) at the Cle Elum Dam in Washington as part of an ongoing effort to rehabilitate the area’s fish population.

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In the wild, the fish thankfully don’t have to be flung manually into the air lock; if all goes well, they’re attracted naturally through a combination of habitat mimicry and manipulation to enter the chamber on their own. (This is called “volitional entry” because the fish supposedly do it of their own will, though in practice it looks more like they’re enticed into a small enclosure with nowhere to go but forward. In fact, a 2018 study of the experiment notes that while the fish had an opportunity to swim out of the enclosure, “most failed to do so.” Perhaps the fish’s “failure” to escape indicates some kind of willing participation?)

You may be thinking at this point: Why go to all this trouble? Why exactly do fish need tubes? Is this really all just an excuse to create a giant salmon cannon for fun and profit?

As it turns out, no. The “tube” may look fun, but it’s actually a serious effort to solve a problem that environmentalists have been battling for years.

Humans are good at destroying fish migration and bad at rehabilitating it

The fish tube is just the first in a long line of attempts to solve the basic question of how humans can help stabilize the natural rhythms of the environment — specifically, fish migration.

The question of what to do about fish migration wouldn’t really exist were it not for man-made dams. Dams physically block the paths fish take to their annual spawning grounds; they also turn running water into still water, which, to put it bluntly, confuses the hell out of fish. The still water also increases the water temperature, which can further endanger migratory fish. And on top of all that, the dams basically wreck river habitats by preventing species from organically interacting with each other — what ecologists call “aquatic connectivity.”

But so far, all of the solutions that have come along to work around dams and aid in fish migration have also come with their own share of environmentally destructive problems.

For most of the 19th and 20th centuries, as hydroelectric dams began to irrevocably alter the environment, scientists introduced “fish ladders” to help salmon and other migratory fish adapt from location to location. The idea was that the fish would “swim” upstream by hopping up the carefully constructed ladders.

In theory, fish ladders operated by simulating the way migratory fish swim upstream in real life. But in practice, modern science has deemed the whole fish ladder concept a giant failure. A 2013 study found that only 3 percent of one species actually made it from the first fish ladder to the last fish ladder on its traditional migration route, while other species were simply prohibited from using the ladders at all, meaning their whole migration route was destroyed.

Other attempts to help the fish migrate have included “trap and haul,” which is exactly what it sounds like: manually trapping and transporting the fish over the required distances, often in water-filled tankers, barges, or helicopters. This is, as you can expect, dangerous and stressful for the fish. It works by tricking the fish into a tanker truck that’s acting like a giant fish bowl — so basically it’s a lot like the climax of Finding Dory with less fish rebellion and fewer attacks by sentient octopi.

NOAA Fisheries
This is the system for fish “trap and haul” — it basically tricks fish into climbing a “fish ladder” and then traps them in a giant fish bowl.

Trap and haul systems inevitably create lots of new problems for the fish subjected to them, however. In 2017, researchers found that in addition to seriously stressing out the fish, the transport ride dazes and confuses them so much that when they’re finally released back into the wild, the fish are left vulnerable to predators and can even forget how swimming works.

As a bonus, both fish ladders and trap and haul can make life unpleasant for communities of fish that are further downstream, or in tributary environments where there’s one main transport system along the main river.

At this point, you might be wondering: Did the country ever devise wild crazy ways to migrate aquatic creatures before this? Are you kidding? This is America. Of course we did.

Has the country ever shot aquatic creatures into the air before this? (Obvs.)

In 1948, the Idaho Fish and Game company decided that the best solution to the growing problem of humans and beavers sharing habitat around pristine regional lakes was to, er, completely relocate the beavers to less attractive lakes. Sounds simple, right?

In fact, it turns out it’s kind of hard to uproot a bunch of animals who’ve spent all their lives in one place, and who come equipped with very sharp teeth. The method of relocation the Idaho parks system came up with involved more “trap and haul”: Conservation officers trapped the beavers and placed them into large, stuffy crates, which they then manually transported over land using horses and mules. If the beavers survived this rough treatment, which lasted several days, the conservation officers then put them on planes.

What happened next pretty much has to be seen to be believed: They then flew the beavers on planes to the new location, and parachuted them from the sky. (Content warning for rough handling of animals, blatant animal cruelty, and general chaos.)

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The beavers, not being natural aviators, were reportedly left dazed by this. What they couldn’t know as they were hurtling through the air is that before they were sent on their great trip, a single beaver — named “Geronimo” for the purposes of this experiment, because Americans are just hilarious — had suffered this same fate repeatedly in numerous trial runs in which he was catapulted from 150 meters above the ground.

Miraculously, only one of the 76 beavers died in the great beaver drop. The man who engineered the experiment, Elmo Heter, wrote in his research summary of the experiment that the lone casualty came as a result of that beaver’s own incompetence:

On the first drops, lightweight lashings were used on the sling ropes, and one of these broke before there was sufficient tension from the shroud lines to hold the box closed. One beaver worked his head through the small opening thus made for him, and managed to climb out onto the top of the box. Even so, had he stayed where he was, all would have gone well; but for some inexplicable reason, when the box was within 75 feet of the ground, he jumped or fell from the box.

For some unfathomable reason, after 1948, the beaver drop never happened again.

Is the fish tube really good or is it secretly bad?

It’s understandable to worry that the fish tube might be another way of humans torturing animals under the guise of attempting to “help” them deal with manmade environmental collapse. But unlike most methods of transporting fish, this one came about by chance rather than intention.

The Whooshh tube technology used to be devoted to transporting fruit over significant distances. As Whooshh’s website tells it, the catalyst for a change came in 2013 when the irrigation of a California fruit orchard had been entirely sacrificed so that the water could be diverted toward salmon migration, thus killing off the orchard. Whooshh’s founders then realized that its services could also solve the problem of helping salmon complete migratory passages in a rapidly changing environment — and since the system relies on air pressure rather than water, there’s no need to deplete irrigation systems of their water.

The results of the tube’s implementation in the years since have primarily been tentatively positive. Research published in 2016 found that the tube didn’t harm the salmon that made the great waterslide ride. However, a 2018 federal report on the Cle Elum Dam trial does bear some striking resemblances to the 1948 beaver drop.

For one thing, the report noted that initially the survival estimates of the sockeye salmon recruited for this experiment were very low, at just a 36 percent survival rate on the first release day. Part of the reason for this is that researchers were supposed to have a cadre of extra fish to help them “test and calibrate the system” before deployment — much like Geronimo, the guinea pig beaver.

Since researchers had far fewer “extra” fish than expected, the number of “official” fish who initially went through the tube were essentially also serving as test fish — and they had a significant mortality rate. Compared to a regular reservoir release system, where the fish had an 85–100 percent chance of survival, the fish tube salmon had a survival rate between just 36 percent and 75 percent.

However, this run of the fish tube was just its first real deployment in the wild, and the Whooshh team has apparently since been busy creating all kinds of fish transport products, including fish ladders and trap-and-haul devices. (Vox has reached out to Whooshh for comment.) Presumably, this technology, like any other, will continue to improve. And in the meantime, there are always water slides.

Vox – All Go to Source
Author:

Aja Romano

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