The secret of a fish with a transparent head is revealed

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

For a long time, the small-mouthed macropinna did not allow zoologists to sleep well. Her transparent head and unusual cylindrical eyes remained a mystery to them. The answer was found only in 2004.

Thanks to the transparent shell on the head, the fish can observe what is happening around it. But the biggest surprise came from her eyes. Taking a look at the image, guess where they are?

The holes above the mouth, which were originally thought to be eyes, actually turned out to be the organs of smell. And what is inside the transparent head and very much resembles 2 green hemispheres, in fact, turned out to be the eyes of a fish. They are separated by a thin bone septum.

In the light, the eyes become bright green. This is due to the content of a special yellow pigment in them, which filters the light and reduces its brightness. I would like to remind you that many deep-sea fish have poor vision. This cannot be said about the macropinna, so it should protect its eyes from the bright light that it may encounter when climbing up to the upper water column with its prey.

The world learned about this fish only in 1939, when it accidentally fell into fishing nets. Its study and primary description was taken up by William Chapman. But due to the deep-sea habitat, it was not possible to study this fish in more detail, and you can take little from one sample. In addition to this, with a sharp change in pressure (from depth to surface), its transparent shell, which protects the eyes, was torn.

And only in 2004, scientists managed to see this fish in its natural habitat at a depth of 500-800 meters. This was made possible thanks to scientists from the Monterey Bay Aquarium Research Institute and the deep-sea ROVs, which filmed the video and took the first pictures of the transparent-headed fish.

The body of this small fish, 10 - 15 centimeters long, is covered with dark scales. Despite the large pharynx, the mouth opening of the fish is quite narrow, which is why it has to monitor the size of the prey. When swimming in a horizontal position, the fish's tubular eyes are always directed upward. Thus, she looks out for her prey in the upper layers.

And after 5 years, in 2009, they also managed to catch several specimens of fish and observe their behavior in a special aquarium. And here are the results the scientists came to. It turns out that the fish's tubular eyes can rotate. This happens during hunting, when the fish, having noticed prey, positions its body vertically.

Various crustaceans, tentacles of siphonophores, cnidarians and other zooplankton were found in their stomachs. Slowly swimming in the water column, the fish looks up. As soon as she notices a tidbit above her, she swims under it and moves the body vertically to grab the prey. At this moment, her eyes move 90 °, leaving the prey in sight.

Judging by the fact that she has to deal with the poisonous stinging tentacles of the siphonophore, the integuments of this fish are immune to their poison, and the eyes are reliably protected by a transparent shell.

Fish with a transparent head inhabits the subarctic and temperate waters of the Pacific Ocean: the Kuril Islands, northern Japan, the Bering Sea, the western coast of Canada and the United States, as well as in the region of the Gulf of California.