16 new species of fish have been discovered this year by a team of marine biologists. But all of them have a particularity: they are ‘ultra black’, they absorb more than 99% of the light that reaches their skin , thus making them practically invisible to other deep-sea fish.
The researchers, who published their findings in Current Biology , captured the species after casting nets more than 200 meters deep near Monterey Bay in California.
Counteract bioluminescence
Bioluminescence is common at such depths. But what if deep sea fish don’t want to be seen? To counteract bioluminescence, some species have developed ultra-black skin that is exceptionally good at absorbing light.
Only a few other species are known to possess this strange trait, including birds of paradise and some spiders and butterflies.
After examining skin samples from these new species of fish under the microscope, the researchers discovered that it contained a layer of organelles called melanosomes , which contain melanin, the same pigment that gives human skin and hair its color. This layer of melanosomes absorbs most of the light that reaches them.
But interestingly, this unique disappearing trick has not been passed down to these species by a common ancestor. Rather, each has developed it independently. As such, different species use their ultra blackness for different purposes .
For example, species like C. acclinidens only have ultra-black skin around their gut, possibly to hide the light from the bioluminescent fish they have eaten.
Since these newly described species are just the ones this team has found off the California coast, there are likely many more.