Trivia 054: Rarer than a Sea Bass

Since I was a kid, I’ve loved visiting museums and aquaria (plural of “aquarium”). I’ve visited the New Mexico Museum of Natural History and Science so many times that I could probably lead tours there. I can’t quite say the same of the Albuquerque Aquarium, but I typically won’t decline a visit. Strangely, though, zoos just don’t do it for me. Museums and aquaria, that’s it. I especially love to go to these attractions when I am traveling. It’s fun going to these kinds of places, because different museums and different aquaria will have unique exhibits and animals. For instance, when I visited Japan, I had to go to the Osaka Aquarium as soon as I discovered that they had whale sharks there. Seeing whale sharks had always been a dream of mine, and now I can say that I have checked that item off the bucket list.

Perhaps the reason I like visiting aquaria more than zoos is because you get to see all sorts of animals that live in an environment completely alien to the surface world. You get to see things like giant spider crabs, giant isopods (lots of giant things), cuttlefish, coelacanth, etc. Things get particularly weird once you start descending into the realms where light becomes much more scarce.

The main subject of today’s post is a creature which is only found in the deep ocean – the Barreleye. This freaky fish lives in the ocean’s twilight zone. And it truly does look like it came out of TV show of the same name. This fish has a transparent head, which its upward-facing eyes actually look through.This adaptation allows them to see shadows of fish passing overhead – either prey to hunt or predators to avoid.

Image credit: Monterey Bay Aquarium Research Institute

If nothing else, the Barreleye is a striking reminder of how evolution produces some results which seem stranger than fiction, all for the slightest evolutionary advantage. It is difficult to study creatures like these, though, because their environments are so extreme. Bringing a barreleye to the surface usually results in the fish’s organs being damaged by the difference in pressure. There’s a great deal we still do not know about the oceans which cover two-thirds of our planet.


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