Monster fish of the deep

November 7, 2017 by Alex Dook, Particle, Particle

Do bugs gross you out? You haven't seen anything yet. To get some really weird creatures, you've got to look in the deep sea.

Do insects make your skin crawl? What about snakes? There are some seriously gross critters around, but if you think a creepy-looking bug is the worst of it, you're wrong. It gets much weirder.

Enter the black loosejaw, winner of Particle's inaugural WTF (Weirdly Talented Fish) Award.

With huge fangs, an enormous mouth gape and jaws like the arms of a praying mantis, the black loosejaw isn't exactly cute and cuddly. But it's not just its looks that make it scary—the black loosejaw has a special ability that gives it an amazing advantage over other critters down in the deep.

SEEING RED

"The black loosejaw can shine a on prey that most other animals can't see," says Dianne Bray, Senior Collection Manager of Vertebrate Zoology, Museums Victoria.

"It's like they have a secret weapon, akin to hunting with night-vision goggles."

If this ability sounds other-worldly, that's because it is. The black loosejaw lives in the twilight zone—that dark part of the ocean between 200 and 1000 metres below the surface. The twilight zone is so different to our own environment, you may as well be talking about an alien planet.

"In the , colours appear very different to how we see them at the surface. Long wavelength light, especially the colour red, doesn't penetrate very far into the ocean—it's absorbed in near-surface waters," says Dianne.

"Lots of animals living in the twilight zone are red, including jellyfishes, crustaceans and even some fishes."

"Because very few predators are able to see the colour red, red animals are well camouflaged in the deep sea," says Dianne.

"Being red is a great way for to hide in the dark zone."

RED IS THE NEW BLACK—IN THE DEEP SEA

The redvelvet whalefish is one example of a deep-sea red fish that is essentially invisible to almost all other critters in the deep sea.

The black loosejaw, though, not only can see but can also produce it. It has a special light organ and can shine a red light and hunt for food while hiding from potential predators.

But how can the black loosejaw see red when other creatures can't? No one knows for sure, but one theory is the black loosejaw evolved this remarkable ability from snacking on tiny critters called copepods.

EAT YOUR … COPEPODS ?

"Copepods are found all across the ocean. It's thought that, by eating them, the black loosejaw is ingesting the chemicals and bacteria it needs to develop eyes that are sensitive to red light."

But that's only one theory. We won't learn more until we spend some more time down in the deep with the other monsters of the deep.

Any takers?

Explore further: A surprise new butterflyfish is described from the Philippine 'twilight zone' and exhibit

Related Stories

Faceless fish among weird deep sea Australian finds

May 31, 2017

Faceless fish and other weird and wonderful creatures, many of them new species, have been hauled up from the deep waters off Australia during a scientific voyage studying parts of the ocean never explored before.

'Twilight zone' fish swim silently with forked tails

January 19, 2016

An international team of researchers has identified a way to predict which reef fish can live across a greater range of depths, increasing their chances of surviving natural disasters such as cyclones and coral bleaching.

The unique visual systems of deep sea fish

December 22, 2016

If asked the colour of the ocean, most people would rightly say "blue." The reason is that pure water absorbs long wavelength red light very strongly, but lets the shorter blue wavelengths pass. If you cut yourself while ...

A trick of the light: How the hatchetfish hides

May 3, 2017

Hatchetfish, tiny "alien-looking" creatures known for an uncanny ability to hide out in open water, use mirror-like scales to deflect and diffuse light to make themselves invisible to predators, scientists reported Wednesday.

Recommended for you

A world of parasites

May 25, 2018

Alex Betts, Craig MacLean and Kayla King from the Department of Zoology, shed light on their recent research published in Science, which addressed the impact that parasite communities have on evolutionary change and diversity.

Bumblebees confused by iridescent colors

May 25, 2018

Iridescence is a form of structural colour which uses regular repeating nanostructures to reflect light at slightly different angles, causing a colour-change effect.

A better B1 building block

May 25, 2018

Humans aren't the only earth-bound organisms that need to take their vitamins. Thiamine – commonly known as vitamin B1 – is vital to the survival of most every living thing on earth. But the average bacterium or plant ...

Plant symbioses—fragile partnerships

May 25, 2018

All plants require an adequate supply of inorganic nutrients, such as fixed nitrogen (usually in the form of ammonia or nitrate), for growth. A special group of flowering plants thus depends on close symbiotic relationships ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.