Chaenocephalus aceratus, commonly called the blackfin icefish or the Scotia Sea icefish has an elongated, tapered body with a relatively weakly ossified skeleton. It has no scales but has thin, highly vascularised skin.
According to H. William Detrich, a professor at the Northeastern University, the unique adaptations of the blackfin fish to its frigid habitat could provide breakthroughs in human medicine. He explains that he is amazed by the fact that we can find organisms in nature who have traits that work really well for them but the same trait in humans is a disease. Thriving in the Antarctic waters for this icefish is not easy but it has evolved numerous counterproductive traits. Without scales, it has little armor to protect itself, and its skeleton is so fragile that it’s nearly transparent because of a lack of calcium. However, the most unlikely adaptation of the blackfin icefish can be said to be its complete lack of red blood cells and hemoglobin, things that are vital for the survival of any other vertebrate. The lack of red blood cells in humans can lead to anaemia. But for a fish which lives in ice-cold water, the alteration is a boon.
“Extreme cold causes red blood to thicken, the way maple syrup does when it’s left in the fridge. The lack of red blood cells means icefish blood is particularly thin, making it easier to circulate in the cold” Detrich comments. He further adds “With the information that is available in the genome of this icefish, and of other icefishes that we’re involved in sequencing, we may be able to drill down on the question of how this unusual trait developed”. The icefish must have had evolved drastically. Being scaleless means oxygen enters the bloodstream directly through the skin. Extra-large gills and an oversized heart pull additional oxygen out of the water and circulate it faster. Expanded capillaries help to transfer that oxygen into tissues.
Though researchers don’t know the meaning of these changes yet, they believe that investigating the icefish genome could help scientists better understand human health issues associated with night-shift workers, osteoporosis, and various forms of anemia, to which Detrich says “The solutions they’ve achieved may be transferable to the world of biomedicine”.
Shahjadi Jemim Rahman