In an exciting new study conducted in the United States, scientists have discovered that hogfish, a type of reef fish, have the ability to “see” with their skin. This unique form of imaging allows the fish to detect its own color and adjust its skin accordingly to blend in with its surroundings. The findings shed light on the amazing adaptations of these fish and provide insight into their behavior and survival strategies. The study was published in Nature Communications
The importance of color to boarfish
For humans, color choice is often a matter of personal preference or fashion. However, for boarfish (Lachnolaimus maximus), choosing the right shade is a matter of life and death. These fish live under the constant threat of predators and must be able to camouflage themselves effectively to avoid being detected. Their ability to change color is critical to their survival.
From female to male: Transition
At about three years of age, kaban fish undergo a unique process of transitioning from female to male. Once they become males, they assemble a harem of young females to mate with and protect. The ability to change skin color becomes particularly useful at this stage, as it helps males attract females and deter rivals.
Scientific basis for skin color change
Like other animals such as octopuses and chameleons, boarfish use specialized cells called chromatophores to change skin color. These cells contain pigments that can spread or clump together, changing the fish’s skin tone. By manipulating these pigments, the hamsterfish can adjust to its environment and remain undetected by predators.
Detection of cells producing opsin
Intriguingly, researchers have discovered that boarfish possess light-sensitive molecules called opsins, which are located in cells just below the chromatophores. These opsins are most sensitive to short, blue wavelengths of light that can pass through the chromatophores. The amount of opsin secreted varies with light levels, suggesting that it plays a role in regulating pigment levels in the chromatophores.
Consequences of cutaneous vision
This discovery suggests that hogfish are able to “photograph” their skin from the inside out, giving them valuable information about their appearance. This form of skin vision is likely less demanding than relying solely on vision to detect color, as it acts as a simple light detection mechanism rather than processing complex visual information in the brain.
Expert opinions and future research
Marine biologist Sønke Johnsen of Duke University calls this study “an excellent dissection of a novel sensory feedback system.” He emphasizes that sensory feedback is still an area that technologists are struggling to fully understand. Further research is needed to determine exactly how opsins affect chromatophores and how this unique form of skin vision evolved in hogfish.