Reproductive characteristics are compared of the nototheniids Trematomus bernacchii and T. hansoni and the channichthyid Chionodraco hamatus caught in summer at Terra Nova Bay (Ross Sea) and caught all the year round in the waters off Casey Station (Mawson Sea). Whilst spawning of T. bernacchii took place in October–November off Casey and probably at Terra Nova Bay, the spawning period of T. hansoni differed between the sites (September–November off Casey, December–February at Terra Nova Bay). The spawning period also differed between sites for C. hamatus (August–October off Casey, December–February at Terra Nova Bay). Fecundity was higher and egg size was lower in nototheniid species (c, 8000 eggs of 3–4 mm) than in channichthyid (c. 4000 eggs of 4–5 mm). Moreover, the fecundity was lower and egg size higher in the specimens from Terra Nova Bay when compared to Casey.