Deepest fish ever caught on camera off Japan

https://www.bbc.co.uk/news/science-environment-65148876

by mywacaday • 3 years ago

167 64 3 years ago

bbc.co.uk

dmix2• 3 years ago

Likewise, their approach to food - they are suction feeders and consume tiny crustaceans, of which there are many in trenches.

I remember James Cameron’s dive and the main life pictured was crustaceans. I’ve also read they are a significant amount of life in underground aquifers [1] was crustaceans, which also had blind reptiles which also fed on crustaceans and had transparent skin similar to those snailfish. I’m curious what makes them so unique to flourish in these sorts of places.

[1] https://www.americanscientist.org/article/creatures-of-the-d...

bobthepanda• 3 years ago

I would imagine it is the extreme pressure. At that kind of depth you either need a really strong body and small surface area (tiny crustacean) or a gelatinous body where that doesn’t matter (snailfish). Those are probably disadvantageous at lower pressure environments. (I’m curious how molting would work at high pressures though, since the crustacean would lose its shell.)

as far as blindness, there’s not really visible sunlight reaching there, so sight probably doesn’t do a lot, and eyeballs are squishy.

Retric2• 3 years ago

Creatures living in the deep simply equalize their internal and external pressures and don’t feel the pressure as some kind of weight they need to withstand.

This is why when you bring them to the surface quickly they die from the sudden decrease in pressure. As to eyes bioluminescence is common in the deep and nothing would bother if nobody had eyes.

MBCook• 3 years ago

Another commenter posted a link to a 2014 article that explains how the fish can survive so deep.

https://www.bbc.com/news/science-environment-26423203

It says that fish use the TMAO protein to protect themselves from pressure. But other organisms use a combination of multiple proteins and that apparently lets them survive higher pressures.

So it seems the fish would basically need to re-evolve how to handle pressure, but in a different way, to be able to go deeper.

flangola7• 3 years ago

If they're born and live at that depth isn't the pressure equalized inside and outside of them?

nntwozz• 3 years ago

If you ever wondered how they survive the pressure, from wikipedia:

TMAO (Trimethylamine N-oxide) is found in the tissues of marine crustaceans and marine fish, where it prevents water pressure from distorting proteins and thus killing the animal. The concentration of TMAO increases with the depth at which the animal lives; TMAO is found in high concentrations in the deepest-living described fish species, Pseudoliparis swirei, which was found in the Mariana Trench, at a recorded depth of 8,076 m (26,496 ft).

dmix2• 3 years ago

Neat, the wiki for that fish:

https://en.wikipedia.org/wiki/Pseudoliparis_swirei

Compared to shallow-water snailfish, Pseudoliparis swirei has several unusual adaptions for its dark and high pressure habitat, including transparent skin that lacks pigment, certain organs and eggs that are enlarged, the muscles are thinner, the ossification of its bones (notably the skull) is incomplete, it appears to have little or no ability to see, there are mechanisms that allow proteins in its body to still function, and differences in the cell membranes for maintaining their flexibility.

transcriptase• 3 years ago

An interesting case of evolution. In theory the first populations to become fixed for an allele or allelic combination that results in even a small increase in TMAO would be able to access previously untouched feeding grounds and flourish for some time.

another2another• 3 years ago

Probably also avoid predators, since they seem to be pretty much by themselves down there.

crazygringo• 3 years ago

Fun fact: the (in)famous Icelandic "rotted shark" (hákarl) food is rotted/fermented in order to remove the toxic TMAO (and urea):

https://en.wikipedia.org/wiki/H%C3%A1karl

Mistletoe• 3 years ago

Chef Anthony Bourdain described fermented shark as "the single worst, most disgusting and terrible tasting thing" he had ever eaten.[2]

Ok that’s saying something.

Kaibeezy• 3 years ago

So what’s natto’s excuse?

fallingknife• 3 years ago

Is this why they expect this fish is near the depth limit? Does this mechanism stop working at higher pressures?

fwlr• 3 years ago

Yeah, the cited depth limit of ~8.5km appears to be based on “fish use an osmolyte called TMAO to protect their proteins from pressure, and below 8.5km the concentration of TMAO required is so high that it inhibits cell function”. Apparently crustaceans get deeper by using five different osmolytes at once instead of relying on TMAO. (Info from helpful comment by mytailorisrich in this thread https://news.ycombinator.com/item?id=35403838)

Waterluvian2• 3 years ago

At 8km down, they are experiencing more than 80 megapascals, or 800 times the pressure at the ocean surface.

Is this somewhat a coincidence or is this the beauty of the metric system?

dakial1• 3 years ago

This is rounding. 8km would actually be 80304.7 kPa. So not as beautiful as you imagine.

Waterluvian2• 3 years ago

I’m guessing the salinity of the water might affect the pressure?

elorant• 3 years ago

Every ten meters pressure raises by one atmosphere. So I'd say it's just a coincidence.

Ekaros• 3 years ago

I think it is just that gravity happens to be 9,81 m/s^2.

On other hand 1kg being equal to 1 litre of water is by design in metric system.

Other happens stance is that pressure on surface is about 101 325 pascals.

So things work out that way...

fredley2• 3 years ago

I'm reasonably sure they're not identically accurate any more, but good enough for the kitchen.

The kg was initially defined by the mass of the water, but as the kg has been redefined it's drifted a tiny bit.

amelius• 3 years ago

Those factors of 10 don't really look so nice if you use e.g. the binary number system.

ralph842• 3 years ago

Indeed. And the SI defining constants are downright ugly.

mytailorisrich• 3 years ago

I've found a 2014 article by the BBC that explains why fish are not expected to survive beyond about 8,000-8,500m:

https://www.bbc.com/news/science-environment-26423203

bjelkeman-again• 3 years ago

From the article

It rests on the particular molecular mechanism they use in their tissues to withstand crushing pressures. To go deeper would require fish to evolve some other mechanism, the team tells the journal PNAS. The all-important molecule is a so-called osmolyte called trimethylamine N-oxide (TMAO). It is what gives fish their “fishy smell”. TMAO acts to stabilize the proteins fish use to build and maintain their cells. Without its presence, the proteins would be distorted by the high pressures found at depth and stop functioning.

culi• 3 years ago

tl;dr: Fish rely on an osmolyte called trimethylamine N-oxide (TMAO) to stabilize the proteins used to build and maintain their cells. The concentration of TMAO seems to be extremely reliably correlated with depth and we know that at a certain concentration TMAO makes proteins too stable to work correctly.

Other organisms like crustaceans are able to occupy deeper parts but they use 5 different osmolytes for this purpose whereas fish have only ever been observed using this one.

ericrallen• 3 years ago

I just recently read the Brilliant Abyss[0] and it was a really interesting look at the deep ocean and the complexity of life down there.

If this kind of thing interests you at all, I highly recommend it. I didn’t know much going in, but found it fascinating.

[0] https://helenscales.com/portfolio/the-sea-beneath-us/

joshuahedlund• 3 years ago

I just read this as well, excellent and fascinating stuff! I thought I already knew a lot about “deep ocean life” but most of it was brand new to me!

terlisimo• 3 years ago

DSSV Pressure Drop sounded like a Culture ship name to me so I looked that up. It's not, but the name of the DDSV, "Limiting Factor", is. Apparently they also named their utility boats after Culture ships.

To those who don't know: "The Culture" is a... society(?) of godlike AI ships/minds from the series of SF books by Ian M. Banks.

SpaceX named their landing barges after Culture ships too, the "Of Course I Still Love You", "Just Read The Instructions" and "A Shortfall of Gravitas".

https://theculture.fandom.com/wiki/List_of_spacecraft

andrewflnr• 3 years ago

There's definitely an MSV Pressure Drop on that page, under the list of ships in Hydrogen Sonata. :)

cpeterso• 3 years ago

And that wiki directly mentions DSSV Pressure Drop because the expedition support ship of the Five Deeps Expedition has utility boats named after Culture ships: Little Rascal, Liveware Problem, and Learned Response.

bmitc2• 3 years ago

What does water "feel" like at that depth? There is a lot of weight felt I guess from the pressure, but is it thicker to swim through in some sense?

sixQuarks• 3 years ago

I’m wondering the same thing. You can see their fins flopping around as if it’s regular depths

RicoElectrico• 3 years ago

Water is incompressible, so I think it should behave similarly. Even viscosity remains within a few precent [1] (Mariana Trench is around 100 MPa)

[1] https://www.engineeringtoolbox.com/absolute-dynamic-viscosit...

bmitc2• 3 years ago

Interesting. Thanks! Upon doing some searching it seems that the water at the bottom of the Mariana Trench is just 5% more dense. I didn't realize that water was that resistant to being compressed.

dinvlad• 3 years ago

I wonder if this fish will be crucial to the survival of life on Earth, if the climate change gets out of control. I would imagine the conditions at the deepest levels of the ocean won't change much, allowing their natural habitat to continue.

gnatman• 3 years ago

And in fact they’ll thrive as more and more detritus rains from above!

xwdv2• 3 years ago

It infuriates me when they bring these fish up to the surface, killing them painfully as the decompress into disgusting blobs.

867-53092• 3 years ago

define pain

xwdv2• 3 years ago

It would be easier to show you.

philihp• 3 years ago

The scientists said they were sorry.

neitsab• 3 years ago

Surprised no one shared this one yet. In case you've never seen it: https://neal.fun/deep-sea/

2wrist• 3 years ago

That’s ace! You don’t expect to see some animals dive that deep!

pvaldes• 3 years ago

I can imagine similar tricks and shapes on life forms from Jupiter's Europa

penguin_booze• 3 years ago

Dear fish, congrats on meeting the human race. Now please stay away from us at all costs--no other species had had a good time having met us.

Your affectionately, a regular, concerned, human.

blackoil• 3 years ago

Must be something due to lack of light and pressure, but all deep water fish seem to be so ugly!

Deepest fish ever caught on camera off Japan

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