Why Antarctica's Clear-Blooded Fish Guard Millions of Nests

Five hundred metres beneath the Weddell Sea, the seafloor is covered in nests, and in each one a fish with almost clear blood stands guard. This is the story of one of those guardians, and sixty million neighbours around him. We follow Jonah, a Jonah's icefish, through the biology that lets a fish live without red blood, and the discovery of the largest fish breeding colony ever found on Earth. CHAPTERS 0:00 Five hundred metres down 0:37 Meet Jonah 1:28 The fish with clear blood 4:15 One nest, nearly two thousand eggs 5:30 Sixty million nests 7:06 The hunters above 8:05 Why guard millions of nests? SOURCES Purser et al. 2022, "A vast icefish breeding colony discovered in the Antarctic", Current Biology 32 Ruud 1954, "Vertebrates without erythrocytes and blood pigment", Nature 173: 848 Sidell & O'Brien 2006, "When bad things happen to good fish", Journal of Experimental Biology 209: 1791 DeVries 1971, "Glycoproteins as biological antifreeze agents in Antarctic fishes", Science 172: 1152 Chen, DeVries & Cheng 1997, Proceedings of the National Academy of Sciences 94: 3811 Near et al. 2006, Molecular Biology and Evolution 23: 2008 Eastman 2005, "The nature of the diversity of Antarctic fishes", Polar Biology 28: 93 Kooyman 1966, Science 151: 1553 Alfred Wegener Institute press release (2022) ABOUT THIS EPISODE Jonah is a representative character: his name and his fin notch are ours, and the study records "one adult fish guarding each nest" without saying whether guardians are male or female. Every other behaviour and number comes from the sources above. Visuals and narration are AI-assisted. Next episode: at the other end of the world, a walrus mother faces the largest land predator on Earth. #Icefish #Antarctica #DeepSea