Based on their observations and those of other authors, Eastman & DeVries (2000) summarised the life cycle of D. mawsoni as follow: the juveniles up to 12 cm total length live in the surface waters near the continent and feed on adult euphausiids and larval fish (Pakhomov and Pankratov 1992). When specimens reaching 18 cm of total length, they descend to within 100 m of the bottom at depths of 300-500 m and assume a bentho-pelagic existence. They remain in coastal waters for several years, feeding primarily on fish (Pakhomov and Tseytlin 1992). D. mawsoni attaining sexual maturity between 90-100 cm of total length an migrate north to the oceanic waters between the shelf break and the Antarctic Polar Front. These records are based exclusively on specimens of D. mawsoni taken from the stomachs of sperm whales (Yukhov 1982). Most occurrences are 926-1111 km from the coast, about half the distance to the Polar Front, but other captures indicate that some individuals travel as far as 1666 km from the coast (Yukhov 1982). These northward migrations take place early in the austral summer. While in oceanic waters, D. mawsoni occupy the mesopelagic zone (300-600 m), with a preferred depth of 500 m, and feed on squid for a period of 1-2 years (Yukhov 1982). The same author speculated that D. mawsoni return to coastal waters for spawning several times during their life, although they may not spawn every year. In McMurdo Sound most D. mawsoni are caught from late September to early December, with set line catches peaking in October/November (DeVries 1998). The spawning of the toothfish is in late winter/early spring. During November in McMurdo Sound, D. mawsoni are feeding in the clear food-rich waters of the Southern Ross Sea, predominantly on Pleuragramma antarcticum (Eastman 1985). This period of feeding precedes both the annual plankton bloom, when visibility for location of prey is reduced, and the northward migratory phase of their life-cycle.
No one has provided updates yet.