Blobfish - Living in the Twilight Zone

Posted by: Laurie Fish on August 29, 2010 at 1:59PM
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Imagine, if you will, a distant planet.

With mid range water levels reaching 800 meters in depth. Here the pressure is 80 times that of Earth’s sea level, exceeding 1200psi. This is a hostile environment where life forms have adapted to survive the harshest conditions – minimal light, a meager food supply. It’s 5 degrees Celsius. Aliens that inhabit this environment, have little need for bones. Instead they have evolved into organisms without air chambers; many are made of a gelatinous material able to handle the 200,000 pounds of water pressing down on them.

You have just entered the Twilight zone

You don't need to travel to a distant planet, in fact, it's here on earth. We know more about the moon than we do about the middle ocean, or Mesopelagic zone. It is called the twilight zone because it sits between the light enriched waters above and the absolute dark waters below. As inhospitable to humans as outer space, it is home to the most extraordinary life forms - curiosities of which we know very little. Inhabitants include siphonophores. Creatures with no heart, no brain, no skeleton and numerous stomachs. They are efficient predators some growing longer than a blue whale.

Deep trawling fishing nets have captured another middle ocean oddity off the shores of Australia.

It is the blobfish (Psychrolutes marcidus) and it is something out of the twilight zone. This popular picture of a dead blobfish has generated a lot of buzz. Of course you wouldn’t look so hot either if you were jettisoned from your natural habitat several atmospheres below sea level. Aptly named due to its gelatinous form, this ridiculous looking fish has a yet unexplained oversized nose, and a head and body that taper back into small, flat tails. They must have a great personality...because, well, they’re not much to look at.

Treehugger.com mentions the impact of commercial fishing on these mid-level waters and specifically the blobfish in Extinction Threatens World's Butt-Ugliest Fish by Kimberley Mok, Montreal, Canada on 02.6.10.

Dining in the twilight zone.

Fed by a fraction of falling organic matter from the more hospitable epipelagic zone, some twilight zone creatures will travel upwards in the night to feed in the rich waters; returning to the twilight zone during the day. A predator is less likely to follow where the waters are dark, cold and oxygen deprived.

The blobfish does not commute.

Its low-density body bobs in the water awaiting its next meal and conserving what little oxygen is available. It glides and bobs, gobbling whatever happens to swim close by. Because of this feeding tactic it is assumed the blobfish has a rather indiscriminate palate – it waits for anything with a pulse. But who knows…really, there is still much to learn about this species and the other life forms inhabiting the twilight zone.

Twilight zone organisms that have been identified include copepods and krill, jellyfish, siphonophores, and of course the famous giant cuttle fish. Squid, including juveniles of the giant squid Architeuthis dux and the considerably larger colossal squid, are also found here. But the big squid live in even deeper waters. That’s where the leviathans do battle. The sperm whale will pass through the twilight zone to hunt in the Bathypalegic zone – the midnight zone. Its lungs collapsing and folding in upon themselves as it reaches depths below 1000meters.

Thought to be descended from animals that lived in shallower water, scientists believe twilight zone animals are highly evolved organisms that were able to take advantage of a different habitat to hunt and reproduce . Location, Location, Location.

So maybe it’s not much to look at.

We may discover that blobfish have unique characteristics worth a second glance. We know very little about this creature. Perhaps it has a curious intelligence like the octopus. Maybe the blobfish has some unique trait like the cuttle fish. Both of these are twilight zone inhabitants. Many life forms of the twilight zone are bioluminescent. But alas, at present, blob fish seem to have no redeeming qualities. Who knows though, we may find that they hold the key to deep water exploration within their gelatinous mass, or a unique genetic code that will unlock a mystery of evolution – a very ugly missing link.

"Over 60% of our planet is covered by water more than a mile deep. The deep sea is the largest habitat on earth and is largely unexplored. More people have traveled into space than have traveled to the deep ocean realm...."