👁️ Discovery of a unique visual cell in deep-sea fish

At the bottom of the oceans, where sunlight struggles to penetrate, life organizes itself in near-permanent darkness. To navigate and survive in this hostile environment, marine creatures have had to develop special senses. It is in this context that a team of researchers made a surprising observation, changing our understanding of vision in vertebrates.

This scientific team has identified, in young deep-sea fish, a type of light-sensitive cell that had never been described before. This particular cell has characteristics mixing two known systems: cones, active in full light, and rods, adapted to darkness. It seems specially designed to function in low-light areas, like the 'twilight zone' of the oceans.


The larvae of these fish were collected in the Red Sea, at depths ranging from about 65 to 650 feet (20 to 200 meters). These tiny organisms, measuring barely 0.2 inches (half a centimeter), are of particular interest. Many deep-sea fish are not born in total darkness; they first grow near the surface before migrating to the depths. Consequently, their visual system must gradually adapt to changing light conditions during their development.

This hybrid cell uses both genes typical of cones and a shape reminiscent of rods. It allows for optimized vision in dim light, a definite advantage for larvae that must feed and avoid predators before descending to the depths. The researchers indicate that this adaptation would represent an evolutionary response to the light constraints of their environment.

The potential applications of this discovery are numerous. In the technological field, understanding the functioning of this cell could inspire the design of more efficient sensors for low-light situations, such as cameras or night vision goggles. In medicine, studying the biological mechanisms at play could provide leads to better understand certain conditions of the human eye.