I always thought that lice were just annoying.

You get absurdly expensive shampoo or spend hours with a comb getting every last one out of your hair, but then you can go about your life trying to forget about the tiny parasites that invaded your personal space. But apparently, we’re not the only species with a big louse problem.

Salmon get them too, and they’re more than just a nuisance. For starters, where would you even find de-lousing shampoo for scales? As fish farmers fight against these underwater lice, they keep coming up with more and more outrageous tools to do so.

Like lasers shot from robots that aim for targets identified by AI. We’re in the sci fi wild west of sea lice removal. And here’s what it looks like: [intro music] The lice that salmon get are parasitic, just like the human variety.

But they’re different from ours in a lot of ways. They live in water, so they’re called sea lice. And they have much more devastating effects on fish than the itchiness that we get.

They’re killing tons of salmon. Which is very bad for the fish, salmon farmers, and the ecosystem at large. For salmon, it’s basically inevitable that a portion of their school will be lost to the parasites.

That’s why scientists and fish farmers are working together to find the most effective de-lousing equipment out there, no matter how absurd it may sound. For example, if you have something clinging to the side of a fish, maybe the solution is to run them through a salmon car wash! Hear me out.

We send salmon into a tunnel where the sea lice get  pressure washed off of them. To be clear, they don’t use the same amount of pressure that we’d use on a car. It would be much lower.

To give you an idea, you can pressure wash a car at 1200 PSI. To pressure wash the sea lice off of salmon, it’s as low as 3 PSI. And while that might not get the mud off your tires, it’s more than enough to handle some sea bugs.

Some of these salmon car washes even use brushes, which makes me picture like the giant rotating brushes you see in real car washes, but fish-sized. They can help brush off more sea lice, and keep the fish moving in the right direction, since you can’t put a salmon in neutral gear. At the end of the ride, the water’s drained away to make sure the sea lice can’t reattach.

And, as bizarre as the whole system sounds, t removes anywhere from 50 to 100% of the adult sea lice from an infested school of fish! Granted, that’s a pretty big range. So if the salmon car wash doesn’t do the job, maybe a trip to the spa is in order.

Just like the car wash, the salmon hot tub is much less intense than what we’d use for ourselves. The lowest temperature that some manufacturers recommend for a human hot tub is 36.7 degrees Celsius. Meanwhile the salmon tub only ever reaches 34.

They also only go into the hot tub for a quick dip, like, 30 seconds max. Which is enough for sea lice to detach but not enough to harm the fish, at least in theory. Since salmon are on the bigger side compared to most fish, they have higher thermal thresholds.

Big fish like them can withstand closer to half an hour at those temperatures. …Assuming they’re healthy, that is. But many of these fish are being treated because they’re not healthy. So even though the hot tub should be below the damage threshold for salmon, for the fish that have already been injured by their unwelcome roommates before treatment, the heat can lead to greater damage.

But if it removes the sea lice, it still might be worth the risk. Researchers at the Norwegian Veterinary Institute have found that the hot tub  method is 75 to 100% effective at removing the lice in the  water around the salmon. It’s just the babies physically attached to fish that we still need to worry about.

For salmon farmed in Chile, 99% of adult sea lice could be removed using the hot tub method, but it only worked on 60% of the youngins. Even if it isn’t a sure thing, I’d still pick a spa day as treatment, especially over some of the other options. Knowing that not all treatment methods work on 100% of the sea lice life stages, it’s tempting to go with something that indiscriminately decimates them all.

Like drugs! Before the mid 90s, pharmaceuticals were the best option. They got rid of all sea lice, regardless of how old they were.

You either put the drugs in the water with fish or in the food those fish were eating. And there are a lot of drugs out there, which all work in different ways. For instance, one works by preventing a pretty important enzyme in the lice’s muscles and nerves from doing its job.

But regardless of the mechanism, many of the drugs have the same end result: paralyzed sea lice. As you might imagine, this was very effective… until sea lice became drug-resistant super-lice. Greaaaaat!

See, farmers accidentally leaned a little too heavily on these drugs and didn’t really slow down using them until 2014. By that point, there were already lice in Norway and Canada, and probably other parts of the world, with adaptations to get around these drugs. Which is why they aren’t really the first thing researchers reach for anymore.

Guess that explains the car washes, and the other weird stuff on this list. Before we move on, all science needs funding. So let’s talk about ours.

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And you’ll get the first 30 days for free. A lot of the research on delousing salmon happens in fish farms because the fish are right there. But sea lice affect wild salmon too.

And in the wild, these salmon usually have other fish around to help them out. They’re called cleaner fish and they eat sea lice for breakfast. … And every other meal. So one all-natural option for  keeping lice populations down is to just add cleaner fish  into the farm ecosystem.

One study published in the journal “Aquaculture” reported the results of using fish called wrasse to remove sea lice. In just three hours, the cleaner fish removed hundreds of sea lice from salmon. I’m talking 96% of all the sea lice there!

So, great! Problem solved! …If only it were that simple. Researchers are still figuring  out the optimal setup, like how many cleaner fish to use, what kind of fish work best… You know, the minor details.

And apparently some cleaner fish have more of an appetite for sea lice than others. Or when they do eat sea lice, they pick off the big, juicy adults first. Plus, there’s more than one  species of sea louse out there, and some cleaner fish  probably have favorite foods.

Who knew the ocean’s garbage  cans have flavor preferences? But the main problem seems to be that cleaner fish like wrasse like to hang out at deeper  water depths than salmon, so they don’t interact much. Which means this might not  be such a viable option.

Now, that same wrasse study found that this might be more of a problem for one species of wrasse, while another was pretty  actively engaged in cleaning. And other studies seem to  have more promising results. So I guess sometimes cleaner fish are really effective and sometimes they’re just more mouths to feed.

Everything else we’ve talked about so far is cool, but a bit low tech. Which might be why some innovators in the delousing field are turning to robots. This completely bananas idea for delousing salmon is straight out of a sci-fi movie: An underwater robot powered by AI that zaps sea lice with lasers.

I’m not kidding. This is not some totally hypothetical idea. It has been in testing since 2014.

The model is called the “Stingray,” and it uses a machine learning algorithm to get to know its enemy. Specifically, the algorithm is trained on images of  previously identified sea lice to pick out future targets. Once it detects sea lice on the salmon, it blasts them with lasers to remove them.

The idea behind the Stingray is that its lasers zap the sea lice dead, but they won’t harm the fish because their scales reflect the beams away. Since sea lice don’t have scales, they should be sitting ducks. …Except they’re not. A study published in 2020, which was the first study to  do any third party assessments, compared how salmon fared with and without the robot.

And there was no difference in the overall number of sea lice after almost two months of testing the AI robots. This is despite almost continuous laser blasts and monitoring by people, which is how AI laser robots should be. Compared to some wrasse  that only need a few hours, or the hot tub dip that  doesn’t even last one minute, this is a pretty disappointing showing from the robots.

But, hey, at least salmon shouldn’t have to worry about an AI robot uprising any time soon, considering their robot companions don’t appear to be capable of much. These are just a few of the ways that researchers are trying to solve a problem you probably didn’t even know existed. Maybe none of these methods are 100% effective 100% of the time.

But some of the solutions come pretty close. And hey, at least they’re all more fun than a special shampoo. [ OUTRO ]