Chionodraco hamatus shows a circumantarctic distribution, although it is mainly recorded on the continental shelf of East Antarctica down to 600 m depth (Iwami & Kock 1990). The lack of haemoglobin in the blood, which characterises these fishes, has probably played a key role in determining their distribution within the cold and highly oxygenated waters of the Antarctic, where metabolic requirements dependent on temperature are low (Eastman 1993). Consequently, several studies on these species have focussed on their blood physiology, as well as on the structure and function of antifreeze components (Kunzmann 1989, 1991; Wells et al. 1990; Egginton 1996; Wöhrmann 1996, 1997).