By Amanda Biederman
Chief Science Correspondent
Millions of years ago, long before Norwegian explorer Roald Amundsen became the first person to reach the South Pole, a group of fishes achieved a remarkable feat: they surrendered their red blood cells.
This family of fishes, known officially as Channichthyidae but more casually as the icefishes, are the only known vertebrates on Earth that lack hemoglobin, the oxygen-binding molecule responsible for the red color of blood. Hemoglobin carries oxygen to an organism's tissues, allowing individual cells to generate ATP and harness energy necessary for the organism's survival.
There are 16 known species of icefishes. My research team is currently collecting and studying three species of icefishes: C. aceratus (the blackfin icefish), P. georgianus (the South Georgia icefish), and C. rastrospinosus (the ocellated icefish). We are also studying N. coriiceps (the black rock cod), a red-blooded species (i.e. "normal") from the same suborder (Notothenioidei).